Suzy's Blog

Local bicycle users group article on Keith's frame

2011-12-06T14:16:00.001+11:00

Keith did a writeup on his frame, which made the front page of the Bikenorth (my local cycling club) newsletter.

Have a look:

http://www.bikenorth.org.au/archives/chainmail/201112/

A brass headbadge

2011-11-25T09:59:00.006+11:00

Here's a headbadge I knocked up from brass for my next frame.

The process was surprisingly simple. I started with an offcut of 1.6mm brass sheet. I polished the front surface with brasso, then cleaned it thoroughly and coated it in a thin layer of etch resist. I overlaid the black part of the little fish logo printed on clear transparency paper, and exposed the resist with ultraviolet light. Then I developed the resist to remove the unwanted stuff, put some tape across the back to protect the back, and bunged the whole thing in an etchant tank for about 30 minutes.

This setup is usually used to make circuit boards, and etch times are usually about 3-4 minutes.

Once I pulled it out of the etchant and washed the resist off, I had this:

I then rolled it to fit a headtube, cut it out, gave it a quick polish, and hey presto. The etching is remarkably deep. I confess I'm surprised at how well it turned out. It was done as a quick experiment during lunch, and I expected all the lettering to disappear.

All that remains is soldering it to the headtube and infilling the etched areas with colour.

A better dropout fixture

2011-11-20T11:16:00.002+11:00

Up until now my jig has made use of a piece of threaded 10mm rod as the "axle" supporting the dropouts. This has been okay, but has been the most annoying thing about the jig.

So I figured I'd improve it. I noticed Alex Meade was selling dummy axles at quite reasonable prices, so figured I'd buy a couple and adapt them to my jig.

First thing I did was to turn up a sleeve to slide over the dummy axle. This is simply a piece of brass tube 50mm long, turned 19.05mm on the inside and 25mm on the outside. I made sure it was a nice accurate slip fit over Alex's axle. I used brass because it doesn't rust, is easy to work with, and is easy to soft solder.

Then I drilled and tapped a hole for an M6 grubscrew in the middle. Now the dummy axle can be held accurately in my brass tube.

I made a pair of flange pieces with 25mm holes in the middle, and 9mm holes to suit my 8020 extrusion. I used 3mm copper sheet because there was some in the scrap bin. Brass would have been fine here as well.

Then I jigged one flange piece on the axle, so it was accurately perpendicular, and soft soldered the two together. This is much like brazing, except that you use lead/tin filler and soft-solder flux. The solder melts at 180 degrees, so the pieces don't distort. Be careful to orient the tube on the flange to ensure the grub screw hole is accessible once it's all assembled.

Finally I bored a 26mm hole through the 8020 extrusion where the original 10mm hole was, and slipped the tube through. I then put the other flange on the other side of the extrusion to provide a bit more support.

If you have a thumping big bit of brass to hand, you could turn flange and tube out of one piece. I didn't, so made it out of what was kicking around.

A basic 8020 spine jig

2011-10-30T11:10:00.012+11:00

One of the most common emails I get is "have you got drawings or plans for your jig?"

I haven't up until now, or at least not decent ones, as the jig I'm using just sort of happened, based on a series of discussions and trial-and-error between myself and a friend.

It's a fairly simple jig - it's nowhere near as user friendly as commercial ones, because there's no easy way to set angles and lengths in it. You cannot use it to design or lay out your frame. You must design the frame in CAD or similar first, then miter the tubes and set up the jig to fit the mitered tubes. Indeed pretty-much all it does do is hold the seat tube, head tube, and dropouts in plane while they're being pinned or tacked. This however is all you need to build a straight frame.

That said, it does so for not a lot of cost and not a lot of machining. There is still some machining required - you'll have to have access to a lathe, and a pedestal drill is pretty-much mandatory.

So the following picture shows the overall arrangement. Key to the design is a spine constructed from 120mm x 40mm 8020 extrusion. It's made in two pieces, with the bit at the back going down the center of the frame axis, and then the front section bolted to the side, so it's offset by 40mm.

Vertical pieces are attached to the spine for the head tube and seat tube, using simple angle brackets, which are standard 8020 parts. The verticals don't need to be at 90 degrees to the spine - they can rotate to pretty-much any angle you want, to accommodate whatever head and seat tube angle your heart desires. Onto these are mounted the bits that actually hold the frame; angle brackets and cones for the top of the seat tube and either end of the head tube, and a machined block upon which the bottom bracket fits.

The dropouts are held in place by a simple piece of 10mm threaded rod through the tail end of the spine.

So here's the parts you'll need from 8020. The distributor near us was happy to cut the extrusion accurately to length for a nominal fee. Note that it's all in metric. If you really desperately must use American fasteners etc., then you're going to have to work out how to do that yourself:

Spine rear piece: 360mm length of 8020 40-4012 profile extrusion.
Spine front piece: 860mm length of 8020 40-4012 profile extrusion.
Seat tube vertical: 780mm length of 8020 40-4080 profile extrusion.
Head tube vertical: 600mm length of 8020 40-4080 profile extrusion.
Small angle brackets: 4 x 40-4302 two hole 40 series inside corner brackets.
Large angle brackets: 3 x 40-4311 six hole center 40 series inside corner bracket.
T-nuts: 24 x 40-1981 economy offset t-nuts.

And stuff from any old hardware store:

Bolts for angle brackets: 20 x M8x1.25, 15mm bolts. Button headed capscrews are ideal. I bought hex headed bolts and have been complaining ever since.
Bolts for BB mounting block and head tube cones: M8x1.25, 25mm capscrews.
Dummy axle: 160mm length of M10 threaded rod, with six M10 nuts.
Bolt for seat post cone: M10 x 80mm bolt, with M10 nut. I actually used a length of M10 threaded rod here, with two nuts.
Bolts for holding spine together: 4 x M10 x 90mm bolts, with 4 x M10 nuts.

Here's the drilling needed for the spine:

Once that's done, just bolt the two pieces together using M10 bolts and nuts.

Here's details of the cones and BB support:

Make these pieces from mild steel. Note that two head tube cones are needed. These are sized for 31.75mm head tubes. If you're going to use other sizes, scale them proportionately or else make a cone that works with either.

The headtube cones are just bolted to the large angle pieces using M8 cap head screws. The seat tube cone is mounted using an M10 bolt, so you'll need to open the hole in the angle piece out to 10mm.

In use I find the best way to set up the jig is by laying it horizontally, loosening off the bolts holding the small angle pieces in, then sliding the verticals around to the right spot. Finally I use G clamps to pull the verticals hard up against the spine before doing up the bolts in the angle pieces - this way the verticals are held snug against the spine. Always measure the angles of the frame itself, not the jig.

Getting the vertical pieces set up just so can be a bit of a pain, but it beats the hell out of a piece of flat bar.

At the moment the dropout supports are simply a piece of 10mm threaded rod with some nuts on it. This is reasonably accurate, but I plan on making a cheek piece that I can use to bolt a proper dummy axle on with.

Must see ad parody.

2011-10-26T15:49:00.003+11:00

Here's a distillation of, well, every ad on telly.

Et Voila (again)

2011-10-18T21:35:00.009+11:00

I figured this frame was worth the effort of a decent photoshoot, so set up a background inside when the light was good (one of these days I'm going to buy some decent studio lights). Anyway, here's some finished photos of Keith's frame and forks.

Please do click on the pictures - each one brings up a huge version where you can study the detail.

Firstly an overall shot of the right side, showing the general decal layout and that gorgeous pearl blue paint.

An overall shot of the front, showing the headtube logo. The logo features our hero being chased by a bigger fish. Little fish have to swim fast, lest they be eaten by the big fish.

The head tube and fork crown, with stainless polished head lugs. The stainless is quite annoying to photograph well, as it catches all manner of reflections.

Another photo of the head lugs and crown, showing the cutout in the lower one, as well as the ergo adjusters. I'm very happy with the way the lug masking worked out.

More detail of that gorgeous lower headlug. I confess this is my favourite picture. I could look at it all day.

Moving now to the seatlug, showing the view from the back including the brake bridge.

A side shot of the seat lug, showing the seat stay attachment and a name decal for Keith. It's a bit thicker than I'd have liked ideally. Next time I think I'll organise a spray mask and paint it on with my airbrush.

I just love the way the stays worked out. Thanks to Anderson custom bikes for the inspiration.

The ultra sexy Sachs front derailleur hanger and bottom bracket.

And more detail of the rear of the bottom bracket, showing the scalloped chainstay bridge. The paint is just so blue.

Finally a shot of the rear dropouts, in nice sensible stainless, so the skewers don't bite into paint.

This frame has surpassed all my expectations. It came together really well. Keith is over the moon. I was concerned that all the stainless would look over the top, so I deliberately kept the cutouts and carving to a minimum. Note also that some of my more tongue in cheek decals (the "handmade in straya" and "keepum fingers" ones) didn't make it. Again, I was conscious of adding too much detail. I think in other colours it could look terrible, but the blue just sets off the stainless perfectly.

Each of my frames has been a little better than the last, but I really don't know how I'm going to better this one, to be frank.

Clearcoating

2011-10-17T07:32:00.008+11:00

So after a day to let the colour coats set up nice and hard, I added the decals, masked the stainless bits again (taking care not to mask all the way to the edge of the lug - the clear on the edges gets removed with a scalpel when I unmask after clearing), then set the frame up in the booth again for clearcoating.

This is the frame after the initial two coats. I put on a really light misting coat first, then wait about 10 minutes for it to start to set up, then put on a full-gloss coat. Reducing with about 20% reducer ensures that I get a gloss coat without excessive buildup - it also makes the paint flow nicely with my 0.5mm nozzle airbrush, which is really a little small for this task - I resemble a whirling dervish when putting the gloss coats on.

I then left it to sit for a couple of hours, mixed up more clear (same 20% reducer) and did another two coats. In this case the first coat was almost glossing, then a wait of 10 minutes, then a full gloss second coat. By doing it like this I get gloss faster on the second coat, so there's much less chance of overspray dulling the finish.

Here's some detail of the masking - note I only mask up to a millimetre or two from the lug edge. A quick wipe with the scalpel once the paint has set up and I've removed the masking gives me a much better lug line than I could get with the masking tape alone. An exception is the top of the seat stays. I masked right up to the colour coat edge here as the geometry of the lug doesn't guide my scalpel.

Here's our hero, courtesy of the decal printing services of Cyclomondo. No, I don't make my own decals any more.

The little fish downtube logo, in a nice white and red. Red and Blue goes together terribly well.

The Columbus Spirit decal. I like Spirit for lugs. It's really nice tubing to work with. I think I'll default to this stuff in future unless there's a compelling reason to choose something different.

If you look closely at the rear brake cable port, you can see how the lug definition is maintained. This is after twelve coats of paint; 1 primer, three base coat, 4 colour coats, and 4 clear coats. The trick is to make each coat super thin.

The fork.

And finally the stem, taken outside to show how it looks in sunlight, rather than the fluorescent light of my booth.

Painting

2011-10-15T16:58:00.004+11:00

After spending a couple of evenings masking the lugs, and then waiting for good weather, I started painting Keith's bike today.

First coat is a nice thin coat of epoxy primer. I add about 25% reducer to the primer to ensure it doesn't destroy all the detail. I prefer not to sand the primer unless I have to - much better to get the metal underneath nice and smooth before the painting starts.

Next are one misting, then two light coats of Auto Air black sealer. The sealer goes on really thin - it's there to provide a nice even tone for the colour coat.

Then four light coats of Auto Air pearl blue. This stuff only takes ten minutes or so between coats to set up, so four light coats only takes an hour or two. As with the sealer, it's incredibly thin, so doesn't hide any detail.

I've just removed the masking. I'll touch up the lug lines with a ruling pen and then add the decals tonight. I plan on starting the clear coats in a day or two.

The pearl blue looks really good in sunlight, and sets off the shiny polished lugs quite well. This isn't Keith's stem - it's one I've done for myself. I thought I'd paint it along with Keith's bike and use it for the photo shoot.

Seven and Eight

2011-10-10T09:11:00.001+11:00

Numbers seven and eight have been started. They're a matching pair of track bikes - one for myself and one for Kristyn.

Here's mine - very standard geometry. It's about a cm smaller in many dimensions than my usual roadie. I've increased the head angle to 73.5 degrees, and increased the seat tube angle to 74 degrees. The goal is for a frame that's good for training on the track through winter, so not extremely twitchy - something to do longer events on.

I've already discussed the geometry of Kristyn's. We're using 650c wheels to get the bars down nicely - otherwise it's surprisingly conventional.

Both frames are to be built with Henry James oversize lugs, Keith Anderson dropouts, and mainly Columbus Spirit for lugs tubes. An exception is the chainstays - I'll use True Temper OX Platinum 28 x 20mm ones rather than the more usual 30 x 16mm ones. This should provide a bit more lateral stiffness.

Now to get ordering parts - I already have most of the lugs, but need to get a few from Henry James (a bottom bracket and seat lug), and need to buy the tubes as well.

And the nice bit. No stainless!

Our new place

2011-10-10T08:41:00.000+11:00

So since we moved out of our awful little flat to a proper house (enabling more frame building with it's lovely large garage), I've settled into a bit of a morning routine. Perry and I get up around 6:30 (having been woken by the cat), I make coffee while he feeds the cat, then we pop some fresh food and water in the rabbit's bowl and put her outside for the day (she stays inside overnight to protect her from neighbourhood cats). Perry usually has brekky out, so I drop him off at the station, then come home and spend an hour or so working on bike stuff before getting ready for work myself.

This has come to be one of my favourite times of the day. The house is nice and quiet because Kristyn is yet to wake, so I sit at the computer, or clean lugs, or whatever, while our cat sits on whatever I'm doing.

Just now there was a bit of a racket outside. I looked up and saw one of our neighbourhood possums wandering along the fence. All is right with the world.

Number six ready for paint.

2011-10-03T09:22:00.001+11:00

Keith's new frame is polished up and ready for paint-prep. It's built with Columbus Spirit for lugs tubes in OS size, with traditional level top tube. It measures 56.5cm long by 53cm high, to suit Keith's relatively short legs and long torso.

The frame is built for road racing, with 73 degree seat tube and 72.5 degree head tube. Lugs are Llewellyn's custodian, in stainless, with substantial modification and customisation.

Firstly some non-stainless content. Here's the only plain steel lug on the bike - the bottom bracket shell. It's an Everest part, which originally had a cast-in chainstay bridge. Given that Keith is a pretty powerful guy, I removed the standard bridge and put a much beefier one in, using a section of seat stay.

I wanted to put it as aft as possible for maximum rigidity, so I scooped out a section using a file to provide a bit more tyre clearance, and filled it in with a down-tube offcut, brazed in with brass so that it didn't fall to pieces when silver brazing the chainstay bridge to the frame. It should be really stiff.

The front derailleur tab is a Richard Sachs one, again in stainless. These things are just so cool it's incredible.

Here's that seat lug, polished to a mirror finish. I know I said previously that I wouldn't do another, but I'm already plotting my next one. Will I ever learn?

The hardest bit to polish was between and under the seat stays, as I couldn't get a polishing mop in there. I did this by hand, using strips of cloth and Brasso.

The head lugs look really classy, I think. I put Bocama-esque cutouts in all the lugs, to make them look a little less heavy. I took a huge amount of material out of the top head lug around the front to lighten it, and removed the ergo cable stops from the lower head lug. I used Llewellyn's downtube-mount cable stops instead, which both look much cooler and ensure there's no interference between front brake and gear cables.

Of course it's all polished to a mirror finish, to showcase my obsessive compulsive disorder.

The dropouts are Llewellyn stainless, to match the fork. Again, polished to a mirror finish.

This is actually the second brake bridge on this frame - I wasn't happy with my first go, so cut it off and tried a second one.

This frame has been quite a bit of work, but I think the results are really worth it.

Just say no to polished seat lugs

2011-09-25T15:44:00.000+10:00

This is my first, and probably last, polished stainless seatlug.

It's not that it was terribly technically challenging to do - the lug prep, mitering, and brazing were not so terribly different to what I normally do with a seatlug, except perhaps the degree of care in mitering the seat stays just so, and minimising the fillet when brazing them into place.

No, the real difficulty is the incredible amount of time it takes to file, sand, and finally polish this lug. Then, just when you think it's pretty good, you braze the seat stays in place and have to go back to 240 grit. Not to mention that it's practically impossible to get anything in between the stays - I'm seriously considering attaching emery to large matchsticks to get in there.

This one (Keith's) is probably at 80%. I've got more work to do under and between the seat stays. I'm very happy with the way the stay attachment has worked out - I think that should relatively easy to mask.

If only it didn't look so good!

I'll do a dozen crowns and headlugs before another seat lug. They're just easy to do - straightforward convex surfaces with plenty of room to swing a file.

Seat stays

2011-09-20T08:09:00.001+10:00

It's always fun when those last two tubes get mitered up, ready to go on. The frame goes from a collection of tubes to an identifiable frame.

So this is the setup I've decided to use for the seatstay mitering. They join just a tad more aft than what I usually do - this will make the gap between them a tad (that's an important technical term - a little more than a squidge, but less than a mite) less than usual.

The plan is to make a silver preform and put this inside the tube, then heat and flow it out. This way I end up with minimal fillet on the outside (so I can polish the lug and have a maskable line), and a decent fillet on the inside, for a nice strong join.

I used just two tools to construct these fillets - a hacksaw and my 300mm half round second cut file.

Oh, and yes, that is a hair elastic holding the seat stays in position.

My other bike

2011-09-14T08:04:00.001+10:00

Apologies to Keith, but this weekend is the annual Ducati owner's club concourse. This year the competition for the 2V monster trophy promises to be pretty fierce.

So I've spent the last week or so prepping my little duc 695, rather than working on Keith's frame.

It's been modified a bit since I bought it, but rather than just adding piles of carbon bling, I've kept the modifications purely functional. The biggest change I made was fitting superbike forks and brakes. The forks came off a 998, and necessitated fitting clipon handlebars and a fair bit of machining work to fit. After I'd swapped the springs for the correct ones to suit me and my monster, the ride is fantastic. I also swapped my brake calipers, master, and rotors for larger 320mm ones with four pistons per caliper. It handles like a dream.

The prep here involved painting the (originally chrome) headlight surround satin black, and removing the original handlebar mounts from the top triple clamp, then painting it satin black as well. Not to mention many hours of patient cleaning and polishing.

Most people simply buy a replacement triple when they do the fork upgrade. I prefer to work with what I have. I'm really happy with the way the original triple has come up. The front looks really cool and purposeful now, with the damping and preload adjusters for the forks poking through. The bar position with the clipons is much better than the original bars, which were rather too high for my tastes.

I kinda like this photo. It's gratifying to see the reflection of my neighbour's house in my tank :)

The 695 is notorious for running very lean from the factory - this ensures it passes strict European emissions tests (a good thing), but does mean the cylinders run rather hot. The paint on my cylinders and heads had gone gooey, and on the front head the gooey paint had picked up lots of road grime, looking really awful.

The exhaust header also went very rusty.

I've removed much of the gooey filthy paint from the front head. At some point I'll have to pull the heads and cylinders off the motor and bead blast the remaining paint, then respray them. This will do for now though.

I thought my headers would have to be replaced, but much elbow grease with scotchbrite pads and WD40 had them looking like new again.

More progress on Keith's frame

2011-08-29T16:13:00.001+10:00

I've made good progress on Keith's roadie. Having mitred all the main tubes, I added bidon cage mounts, front derailleur tab and rear brake cable tunnel. Then I brazed both seat tube and down tube into the bottom bracket, and the lower head lug. I used System 48 for the BB, and 56% silver for the stainless head lug.

Here's the whole thing on the jig:

The BB after brazing. This is the first time I've brazed both down and seat tubes in the one go - it prevents reflow of the seat tube join when I add the down tube later, as I'd done previously. In any case, I'm really happy with the result - I got the filler to flow really evenly without much encouragement.

Here's the lower head lug, immediately after brazing while it still looks awful. The filler just shot straight through this lug. This is my first stainless head lug, and I'm really happy with it.

Same join, after some cleanup with emery and green scotchbrite pad. Next step is to give the lug a nice polish.

After a quick polish (hah!) it looks pretty good:

Keith Anderson dropouts

2011-08-28T09:48:00.000+10:00

I just bought a set of these cool dropouts from Keith Anderson.

When I made my very first frame, I brazed thin stainless plate to plain steel dropouts so that the axle nuts wouldn't chew up the paint. It was successful, but I always wished there was something to let me put stainless in the slot, as well, so the axle itself didn't chew on paint.

These cool dropouts are exactly what I wanted then - nice beefy 4130 plates for strength, with cool milled faces in stainless. I've bought two sets of track dropouts, so will shortly make a pair of track frames (one for me, one for Kristyn).

The plan is to do a little carving - I might put my initials in under the seat stay...

Anyway, the dropouts are very, very cool - beautifully machined.

Fear me!

2011-08-22T14:55:00.000+10:00

For I have a bottom bracket tap, made by Cobra, and courtesy of Peter at Ceeway.

It joins my lovely headtube reamer (also by Cobra) as one of my finest tools.

Now I don't feel quite so bad at parting with Ben's frame, as the proceeds bought me this :)

On a completely unrelated note, I think I have my answer as to how to do the seat stays on Keith's bike, and still polish the seat lug:

Graeme found a pic stream from Anderson custom bikes, showing what he did in a similar circumstance:

I think it looks incredibly cool, so shall shamelessly copy.

My first fork

2011-08-22T10:41:00.000+10:00

I've never built a fork before. I've built five frames, but never a fork. The reasoning was quite simple. A steel fork weighs around 600-750g, depending on steerer length. A full-carbon fork weighs 350-400g (ones with steel steerers are generally just as heavy as steel forks, as all the weight is in the steerer). Carbon forks are cheap and plentiful, and work quite well.

Keith's bike, though, just won't work with a carbon fork. With polished lugs, sticking a bit of black plastic on would just ruin the aesthetics. So I decided to take the plunge and build a fork. Given that it's my first, I stuck to the basics - a 1" EL steerer, raked stainless crown, Nivacrom blades, and Dazza's gorgeous dropouts.

First step (documented previously) was to braze the steerer to the crown with 56% silver filler and stainless light flux. I then turned the crown race seat and gave the crown a polish.

Next I cut the small end of the blades down until they fit neatly in the sockets of the dropouts, cut the other end to length, and assembled the fork in a jig. I then brazed the dropouts to the blades, again with 56% silver filler and stainless light flux.

Once the dropouts had a handle, I took the opportunity to file, sand, and polish them.

I then set the crown sockets so the blades fit neatly, jigged the fork up, and brazed the blades into the crown. Having the jig upside down was very helpful here, as it encouraged the silver to flow right into the join. Again, 56% silver filler and stainless light flux.

I wasn't happy with the thickness of the crown where it joins the blades, so I took to it with a file and thinned it out a little, then sanded and polished it.

Here's the final result. For a first go I think it turned out pretty well.

Progress on Keith's frame

2011-08-18T08:01:00.001+10:00

Here's a test-fit of Keith's front triangle in the jig. The astute will notice that I'm not supporting the top of the seat tube - this is because the design of the stainless Llewellyn seat lug has a shelf in it, that necessitates cutting the seat tube much shorter than I usually would. While it makes it harder to hold in a jig, it's a good thing, as otherwise there would be a thin nivacrom steel ring around the seat post, which would rust on a bike with bare polished lugs.

I'm doing things in a slightly different order this time. Normally I prep tubes (add bidon bosses and cable tunnels etc), and then do the fit-up. This time I'm doing the fit-up first, as it allows me unimpeded access to measure tube angles.

Here's what the head lugs look like at the moment. I've done the cutouts and shaping, and have filed out the casting roughness and given them a quick wipe with 180 grit emery. I'll do the rest of the smoothing and polishing steps after brazing. I still need to do a little setting to get the angles just so.

You'll note I've done the same treatment to the seatlug. I'm still vacillating as to whether or not I want to polish this piece. If anyone has suggestions as to how to make fast-back seat stays work with a polished seat lug, I'm all ears...

Finally detail of the little shelf in the seat lug. I plan to support the frame while tacking with a bit of 27.2mm seatpost pushed down the seat tube.

Next step is to mark and drill for the top-tube cable tunnel, then braze the cable tunnel, bidon bosses, and front derailleur tab in place. It's important to do this before the main tubes are brazed together, because otherwise the brazing heat will pull the frame out of plane, especially with the front derailleur tab, which is asymmetrical.

Coping

2011-08-17T18:30:00.001+10:00

This is how I fit tubes together - called variously coping, notching, or mitering, depending on what dialect of English you grew up with.

Our demo tube today is Keith's top tube. I'm mitering the top tube where it fits against the seat tube.

Step one is to rule a line down the tube - this is used to keep the miters "in phase", so that things line up when you assemble the bike. I like to put the lines along the top of the top tube, top of the down tube, and front of the seat tube. That allows me to line up lug points nicely, and also gives me a reference line for bidon cage mounts.

Next, I download a copy of tubemiter, and type in the specs for the miter I'm doing. I print the result on sticky address label paper. I cut that out and wrap it around the tube.

Now that I know the shape to miter to, I start by making a pair of cuts in the tube with a hacksaw. I get a little closer each time I do one of these.

Flip it over and do the other side, and you end up with a nice little cutoff piece that you can show to all your friends.

Finally I take to the tube with a file. For this miter I used a 200mm long half-round 2nd cut file. One of these days I'll buy some bastard files to speed up the process, but the 2nd cut files work quite nicely. For head tube miters I use a 250mm file.

And that's it. All in less time than it would take to set up a mill to do the work.

No Girls Allowed!

2011-08-11T09:35:00.000+10:00

A bit of a tangential post from what I normally write about here, but please bear with me.

This is what the adult "No Girls Allowed!" sign looks like:

My day job is in electronics. I design itty-bitty little chips that go in radiotelescopes. It's an awesomely cool job that lets me express my creativity in ways I never would have dreamed possible. My workmates are wonderful people, and we have a truly fantastic workplace. To put it bluntly, my job rocks.

But there's one small catch. I am the only female electronics engineer in the place. We have heaps of female astronomers, a few female managers, rather too many female admin staff, and a few female techs. But just the one female engineer. And even then, I'm hardly a typical woman. I ride motorbikes and build bicycles. I used to play footy. Generally things guys do.

So a month or so ago we had a workshop at work for women in science. It was run mainly by the astronomy group, who had a pile of really useful things to say to help women in science careers - stuff around ensuring the workplace is family friendly, making allowances for career breaks for when women take time off to have babies - that sort of thing.

At one point, people noticed that I was the only woman there from the engineering groups, so I was asked what I thought should be done to increase women's participation in engineering. I really didn't know (and said as such), but it did get me thinking about the subject.

This morning I dropped into uni to talk with my supervisor. As I was leaving I passed one of the undergrad electronics labs. You know the sort of place - rows of benches each with an oscilloscope and function generator bolted to them, with a rack of test leads on the wall. All good stuff. I remember many a lab session spent building little amplifiers and oscillators and other cool stuff.

So that's where I saw the sign. A really big one - you couldn't possibly miss it. Right on the door.

No Open Toed Shoes in Lab

Now seriously, this is a uni undergrad electronics lab. All the heavy stuff is bolted to the bench, to stop people from stealing it. The worst thing you could drop on your feet is a multimeter.

But still the sign. It brought back memories of being kicked out of labs as an undergrad myself, for, you guessed it, wearing sandals. That unforgivable sin committed by, what, ninety percent of the female population of any university, at least in summer.

I can see how the reasoning goes - similar reasoning applies in my workplace. "Labs are dangerous places, full of heavy things." "We should ensure people wear the appropriate PPE."

So then some middle-aged male lab manager puts up the sign. To him it appears perfectly reasonable - after all, he wouldn't be caught dead in sandals. Never mind that the computing lab down the hall has just as much heavy stuff that could fall on your feet. Or the library...

Of course, if the PPE needed is safety glasses, or hearing protection, there's some provided, right there, hanging from a hook. Not so with closed toed shoes though, because it's only women that don't wear those.

And so another small barrier is put up between women and a career in engineering.

So in answer to the question that I was asked in the women in science workshop: It's not one thing, it's a multitude of tiny little annoyances. It's the no open shoes allowed sign. It's the dumb little trick question in the HSC physics exam that means that you have to be particularly good at vector maths in order to answer a question that is really straightforward and simple in itself. The list goes on. Each one in isolation isn't going to do any measurable harm, but when they're combined, they're a formidable hurdle.

So if you're in a position where you're making such decisions, please stop and think for a moment if what you're about to impose on people will have a negative effect on women and girls. If it does, then do you really need to do it? The open toed shoes bit is an obvious example - when your work area isn't really any more dangerous than a typical office, don't impose PPE standards that are discriminatory. And when the PPE is truly warranted, have a cupboard full of the things that people can use. You don't expect people to wander around wearing safety glasses all day, do you?

The Sydney framebuilding underground.

2011-08-06T18:21:00.000+10:00

I dropped Ben's frame off last weekend at Cheeky Transport in Newtown, because I know they're one of the few bike shops that has real tools for tapping bottom brackets and reaming head tubes. I do have a reamer for traditional 31.7mm head tubes, but not the 36mm behemoth on Ben's bike.

Today I picked it up, and ran into another local framebuilder, David Bowen of BoBo cycles, who had done the BB tapping, facing, and headtube reaming on Ben's bike for me.

It was neat running into another small-scale framebuilder in Sydney. He showed me a couple of his cool frames. His passion is commuter bikes and fixed wheel bikes, and he does lugs, fillet and even TIG.

Once home, Ben and I threw his Dura-ace group on the frame, and we both got to do a quick ride on the street to see how it feels. It's too big for me, but despite this it still feels lovely and neutral - within a few metres I was able to ride no hands, which is really cool.

The new Dura-ace kit is quite nice to work with. The polished titanium bits and grey anodised aluminium hubs set off the polished dropouts and derailleur tab quite nicely.

Here's Ben riding his new bike. His plan is to race it in master's races.

Teasing Ben

2011-07-28T08:28:00.000+10:00

So we're assembling Ben's new bike on the weekend. I told him when he dropped by last Sunday that he could look but not touch, and that he wouldn't be allowed to touch for a week, while the clear set up nice and hard.

Here are some nice pics of his bike in the dawn light to tease him. I don't think detailed descriptions are necessary. I'll let the photos speak for themselves. Firstly the seat lug:

Bottom bracket, plus polished derailleur tab:

Rear dropouts:

Upper head lug:

Lower head lug, plus ergo adjuster:

Lugwork and fork crown

2011-07-18T20:55:00.001+10:00

So here's the fork crown that I'll use on Keith's bike. It's an LC18, with in-built 6.5 degree rake, to suit straight blades. I've filed, sanded, and polished it, then silver-brazed it to the steerer, then more sanding and polishing. The above photo was taken before turning the crown race seat. The below photos show it after turning the crown race seat.

I've also done a fair bit of work on the Llewellyn custodian lugs. As with Ben's bike, I've cut Bocama-esque triangles in the points and removed the STI adjuster ears. I didn't think there was enough material in the sides to warrant the triangle cutouts I did in Ben's lugs, so instead I scalloped out the sides to make them look a little more skimpy, and cut back the shoulders significantly. On the top head lug, rather than cutting the top skirt down, I removed a whole pile of material from the underside, significantly lightening the lug. This allows me to use a centimetre or so fewer spacers.

What have we here?

2011-07-16T18:31:00.001+10:00

A lovely package arrived in the post yesterday. I opened it up and a whole bunch of tubes fell out. What sort of tubes could they be? Columbus Spirit for lugs, of course, in OS. This stuff is about the pinnacle of tubing. All Nivacrom, lovely thin walls, but with friendly butted sections suited for lugged construction.

More of the package revealed some lugs. These are Llewellyn custodian lugs, in OS size, and in stainless.

Aye, that be right, this one's going to have stainless lugs, and Spirit tubing. Alas it's not for me - it's for Keith. I just get the joy of knocking it together. :)

Keith is a really good mate from way back - He's the sort of guy that's just perfect to sit on - a big hefty sprinter. I've watched his arse for many thousands of kilometres, which is as it should be, because the alternative is not being able to get on his wheel when he decides to sprint.

Keith surprisingly has very short legs. He's a reasonably tall boy, but clearly all his height is in his torso. His off-the-peg Pinarello is a 54, which has a 52 seat tube and 54 top tube. In order to fit on it, he needs a 13cm stem and he pushes the saddle all the way back (9cm from saddle tip to BB), which can't be good for his knees.

I went for a 53cm seat tube (about the same standover height as his Pinarello), but put an extra 3cm in the top tube, for 57cm. This allows him to use an 11cm stem and just 7.5cm saddle setback, but get the same saddle-bar distance. The hope is that he'll be more comfortable and more able to get over the pedals when he sprints. I've set the bar drop the same as his Pinarello - 7.7cm, but allowed provision for him to drop the bars significantly once he gets used to the slightly more aggressive geometry.

Dazza was aghast that I ordered stainless lugs without ordering the parts for a fork as well, so I've relented and will do a matching fork. This is using parts I've had kicking around for a while - a 1" Columbus EL steerer, Columbus Nivacrom blades, and a Long Shen stainless crown (which I've already polished up). This should build up a lovely light fork.

Here's the ingredients that I'll use to make Keith's frame:

Head tube: Columbus Nivacrom 31.7mm.
Down tube: Columbus Spirit for lugs 31.7mm x 650mm
Top tube: Columbus Spirit for lugs 28.6mm x 600mm
Seat tube: Columbus Spirit for lugs 28.6mm x 635mm
Seat stays: Columbus Spirit 16mm, tapering to 12.5mm tips.
Chain stays: Columbus Spirit 30mm x 17mm oval, tapering to 12.5mm tips.
Brake bridge: Silva art 189 with art 362 reinforcement diamonds.
Dropouts: Llewellyn LRD68/SS stainless, 68 degree angle.
Front derailleur tab: Richard Sachs.
BB cable guide: W2081 stainless.
Bottom bracket: Llewellyn OS.
Lugs: Llewellyn Custodian stainless OS.
STI bosses: Llewellyn LL-09-31.7 with Ceeway brass deluxe STI adjuster screws.
Brake cable tunnel: Silva art 150 with art 141 reinforcement diamonds.
Rear derailleur cable boss: Silva art 152.
Bottle bosses: Silva art 471 with art 361 reinforcement diamonds.
Steerer: Columbus EL.
Fork Blades: Columbus Nivacrom.
Crown: Ceeway LC18 stainless.

The head lugs, crown, dropouts, derailleur tab and STI bosses will all be polished. I'm still vaccilating as to whether or not to polish the seat lug. If I do, I'll really have to change my usual fastback seat stay attachment style... Anyway, I'll see. In the meantime I'll get to carving the lugs.

Sorry Ben!

Aargh!

2011-07-16T17:19:00.000+10:00

So this is the activator for my clear coat. Clearly I won't be finishing Ben's frame this weekend.

This puts me in a bit of a bind - I have a couple of litres of Imron clear, and about half a litre each of red, black, and white. They all use this activator. Unfortunately the mob I buy my paint from no longer stocks Imron, and I'd prefer to go with the DeBeer product that they're selling. That means effectively chucking over four litres of paint.

Oh well, I guess I had to make the change at some point.

It's upside down!

2011-07-15T15:15:00.000+10:00

Ben's bike has paint on it - the colour scheme was his idea, to match a favourite jersey. I think it looks kinda cool - certainly very bold.

I've just put the decals on, and am leaving it overnight before putting the clear coats on. This is how the auto-air paint looks immediately after spraying - a nice satin sheen. It's terribly delicate at this point- hence hanging up.

The head tube took a fair bit of patience to mask - I found the trick was to use lots of very small bits of tape, and to press each one carefully into the shoreline with a biro before cutting it with a scalpel. I did the yellow panels first, then the red. On the seat tube there are little orange decals at the transition between yellow and red.

Et Voila!

2011-07-01T08:52:00.000+10:00

So after a few nights through the week burning the midnight oil (or is that LPG?), I'm at the point where Ben's frame is ready for paint. This is where I think frames are at their most beautiful, before the paint (however thin) hides all that delicate detail. Anyway, here are a bunch of pictures.

Please do click on the pictures to see larger versions. Those that come up in the blog are rather small.

Starting with the head tube. I polished up the nice little Llewellyn ergo bosses. They're fitted with brass adjusters from Ceeway. As mentioned in previous posts, the head lugs are Llewellyn Cadenzia, with added cutouts.

More detail of the lower head lug cutouts, and showing the shorelines.

The top head lug has similar cutouts to the bottom. Also visible here is the rear brake line port. It's on the right side, because here down under, we usually run the rear brake on the left lever. By running the brake line around the right side of the head tube, It will then have a much neater bend. That's the theory, anyway!

Turning now to the seat lug, you can see the difference that taking material off the rear skirt section of the lug makes. I think it looks a lot cleaner and more minimalist that the original lug. The seat stays were brazed on with system 48, which builds lovely fillets at silver temps.

More detail of the seat lug. Here you can see the shaping I do to the back of the binder. I love the shape of the top of the Llewellyn seat lug - very organic.

A shot from the other side shows the rear brake cable port, which is in the conventional position. Also, the triangle cutouts. I really like like how these turned out, and will definitely do them again on subsequent frames.

The brake bridge. What can I say? It's the bit you bolt the rear brake to. These bits can actually be a little annoying to braze, as the goal of keeping the cutouts free of silver while putting a fillet on the bridge just a couple of millimetres away is rather contradictory. This is where teeny tips are used.

The dropouts. My fingers are sore.

Here's the bottom bracket area, showing also the chain stay bridge and front derailleur tab.

More detail of the bottom bracket, showing the neat shorelines that are possible with system 48. This stuff builds bigger fillets than 56%, but cleans up readily. The neat thing is that it fills gaps.

And finally the whole thing, to put everything in context. I think the XL tubes look good on this size frame - they make a frame that otherwise would look spindly look more normal. This is 57cm long and 58 tall. It's probably about the smallest frame I'd want to do with XL tubes.

For reference, the frame weighs 1950g. That's for Columbus Life tubes. Contrast that to the 1680g I got for Kristyn's compact frame, with cheaper Zona OS tubes. Yes, the frame is bigger, but I think the XL tubes do have a bit of a weight penalty.

Lugwork - 3

2011-06-23T07:04:00.000+10:00

One final lug to work - I'd cut triangles in the seatlug previously, but had to wait until I could see how the seat stays would attach before doing the back. I mitred one of the seat stays last night and simply traced around the end. At first I thought some triangle cutouts in the long tangs would look good, but decided they were too fussy, so simply cut the tangs down and reshaped the back a little.

Here's the result.

More progress on number five.

2011-06-22T08:38:00.000+10:00

I'm making good progress on putting Ben's frame together. Here's a photo of the front triangle and chainstays in the jig. The XL tube sizes are a tight fit, but it all goes in okay. The top tube isn't brazed in yet - it's just jigged up so I can mitre the seat stays and work out what to do with the skirt section on the seat lug.

Here's a nice macro photo of the lower head lug. I used 56% silver filler with this, and dropped back to a number 12 tip, using the system 48 flux. I'm quite pleased with how it turned out - the amount of filler is good, and I got full penetration without much encouragement. Also shown is one of the ergo cable adjusters. These are quite a challenge to hold on the downtube. These were brazed in with 56% silver filler, using the stainless light flux.

Here's the progress on the bottom bracket. As you can see, I'm yet to mitre or braze in the chainstays. The BB-downtube join was done with system 48 filler, and system 48 flux. I went up to a number 20 tip for this one (I modified my largest acetylene tip for LPG by drilling a counterbore in the end). I really liked using this tip - it let me get very even heating.

The system 48 filler is a little gummier than 56%. I don't get the minimalist shoreline fillets I'm used to with 56%, so there's a little more shoreline cleanup needed. That said, it pulls through really well and fills bigger gaps than 56%. Just the ticket for bottom brackets. I can see myself using quite a lot of this filler.

Finally one of the dropouts. I've got a standard recipe now that works a treat for stainless. 56% filler with grey stainless light flux. I used a number 12 tip here, as the dropout tends to act as a bit of a heatsink. I overdid the filler a little, as evidenced by the excessive fillet in the cutout. Contrast that with the really nice fillet I got on the cutouts on the lower head lug.

Interior cable routing

2011-06-15T09:09:00.001+10:00

Interior cable routing is quite a bit of work, but very rewarding when it works well. I use a two-step process, where I first solder the tunnel to the top tube, and then solder a reinforcement piece over the top. It makes for a lot of work, but I think the peace of mind knowing that the join is nice and solid inside is worth it.

I start by slotting the top tube - I just use a drill and file for this - I aim to get a really neat fit to the angled cable tunnel end. Then I assemble the cable tunnel by cutting the middle piece to length, and soldering the larger end pieces on with 56 % silver.

Next the cable tunnel is inserted into the tube. This can be tricky. Ben's frame has the entry point horizontal on the right side, to make for neat cable routing around the head tube, and then horizontal again on the left at the back. I'm leery of having the cable exit at the top, as that's asking for water to work it's way in.

Apply plenty of flux (I'm using the System 48 flux here, with 56 % silver filler).

And solder the tunnel to the tube, aiming for a small fillet all around.

After cleanup, it looks nice and clean, with a good fillet.

Next, I put the reinforcing diamond on top, ensuring it fits neatly. A little bit of blacksmithing was required to form the diamond so that it neatly fits the 31.75mm XL tube, as they're designed to go on 28.6mm tubes. I forgot to take a photo before fluxing, so the fluxed one will have to do.

And solder it in, again using 56% silver filler and System 48 flux. It's hard to do these neatly, as you have to ensure there's enough filler to fillet the tunnel end, and it tends to go everywhere. Also they're tiny pieces, and easy to overheat. I use a much smaller tip (no. 8) than my usual no. 15 for this work.

Finally, wash the flux off, cut the tunnel down neatly and use emery and needle files to remove the excess filler.

System 48

2011-05-31T07:42:00.000+10:00

I wasn't 100 percent happy with the fit-up of the seat tube socket on the bottom bracket of Ben's bike. The casting was just a bit more sloppy than what I'm used to using with 56% silver.

The issue here is that 56% silver is not at all forgiving of gaps. It flows like water (which is a good thing, as I can get really good penetration when everything is just so), but has practically no ability to fill.

So I asked for advice on the framebuilder's list, and was pointed in the direction of System 48 filler and flux, by Wade Barocsi of Cycle Designs. This stuff is still a silver filler, but is formulated so it's got an ability to fill a little. Like 56%, it's revoltingly expensive. I do wish people wouldn't speculate on silver and push the prices up.

In use it's clearly more viscous than 56%. You've gotta give it encouragement to draw it through the lug. It does though, and the result is really strong, without having to go to higher temperature fillers like LFB. The cable guide on the other side is held on with 56%, and I didn't reflow this join.

The picture shows the result, immediately after soaking the flux off and prior to any clean-up, so it still looks ghastly. You can see it's penetrated 100%, and also that I was a little on the generous side.

Another thing you can see here are pins. I pinned this join, and soldered it out of the jig. I'm quite happy with the result - it's a hell of a lot easier to get access.

Lugwork - 2

2011-05-16T14:09:00.001+10:00

I thought I'd show the process of putting a cutout in a lug.

The lug I'm working on here is the upper head lug for Ben's bike. It's a Llewellyn Cadenzia XLH lug, and I'm doing a little work to it to make it look more like a classic Bocama Professional.

I start by roughly marking where the cutout will be, using a sharpie. Then I put four center punch marks in; one in a little from each of the triangle vertexes, and a third right in the middle.

Next I use a pillar drill to drill a 1/8" hole where each vertex will be, and then a bigger hole in the middle, as shown below:

Next step is to open out the holes to form a rounded triangle. I predominantly use a 1/8" diameter Swiss No. 2 round file to move the vertex around, and a three square Swiss No. 2 file to bring the sides down towards the vertexes:

Once I'm reasonably happy with the shape, I swap to needle files. These are mainly used to reduce the diameter of the vertexes and smooth everything up:

These cutouts have a matching one on the other side, so I do them both at the same time, doing plenty of measuring to ensure they match. The final step with this lug is to round out the cheeks a little to soften the look. Here's how it ends up looking along with the lower head lug, which I did previously:

Lugwork

2011-05-10T21:02:00.000+10:00

I confess this is probably my favorite part of framebuilding; where I get to play around with the lugs and make them look right.

I started by quickly filing and sanding the casting roughness from the derailleur tab and STI cable bosses. There wasn't any real modification done to these, save to file the loveheart cutout on the STI bosses into a rounded triangle, so that it matches the other lug cutouts I plan for the frame.

Next I removed the rack mounts from the dropouts, and cut some small triangles into them. As with the other stainless parts, much of the casting roughness has been files off and I've hit them with some emery. Once they're on the chainstays, I'll do some more serious sanding and polishing.

Finally I went to work on the lower head lug. I first cut a triangular cutout in the tang, and then removed the cast-in STI bosses. They looked a little full then, so I cut more triangles in where the STI bosses had been, and rounded the sides a little. I'm quite happy with the look now.

Next step is to replicate the cutouts and shaping on the upper head lug, and then decide what I want to do with the seat lug.

Ingredients

2011-05-07T09:27:00.001+10:00

Here's the ingredients that I'll use to make Ben's frame (from the top of the picture):

Head tube: Columbus 36mm.
Down tube: Columbus Life 34.9mm x 650mm
Top tube: Columbus Life 31.7mm x 600mm
Seat tube: Columbus Life 31.7mm x 635mm
Seat stays: Columbus Life 17mm, tapering to 12.5mm tips.
Chain stays: Columbus Life 30mm x 17mm oval, tapering to 12.5mm tips.
Brake bridge: Silva art 189 with art 362 reinforcement diamonds.
Dropouts: Llewellyn LRD72/SS stainless, 72 degree angle.
Front derailleur tab: Silva art S286 stainless.
BB cable guide: W2081 stainless.
Bottom bracket: Long Shen LB09-3
Lugs: Llewellyn Cadenzia XLH.
STI bosses: Llewellyn LL-09-35 with Ceeway brass deluxe STI adjuster screws.
Brake cable tunnel: Silva art 150 with art 141 reinforcement diamonds.
Rear derailleur cable boss: Silva art 152.
Bottle bosses: Silva art 471 with art 361 reinforcement diamonds.

Not shown, of course, are the 56% silver rod that I'll use to braze the frame together, nor the paint.

Next step is to do some lug prep - I'm going to cut the STI bosses off the lower head lug, and cut triangles in many of the lugs, to give them a classic Bocama look - something like this:

Then I'll file and sand the casting marks out of the dropouts, front derailleur tab, and STI cable bosses in preparation for polishing once they're brazed in place.

Only then will I start cutting and mitering tubes.

Decals continued

2011-04-29T18:52:00.000+10:00

My first lot of decals have arrived, from Cyclomondo.

I'm quite happy with them - the Gerber printer does quite a nice job. They aren't strictly speaking decals, but instead are printed vinyl stickers, similar to the Columbus etc ones. They're certainly thin enough to be hidden under clear coat.

The hardest part was finding a file format that Greg could read reliably - the software I used to create the artwork (Inkscape) doesn't output the right files for the Gerber printer, so lots of experimentation was required. I ended up sending Greg .eps and .plt (hpgl) files, one of which he was able to work with.

Greg removed some of the black outlining from the head badge - presumably to ensure that it printed well, as the outlining was pretty thin. I put it back with some fine 0.03mm Copic markers :) I confess I quite like hand drawing parts of my decals - fits in with the whole Richard Sachs "imperfection is perfection" thing, and allows me to release my inner artiste.

I think I'll scale up the downtube decals a bit for the next go, as these ones look a little small even on Kristyn's titchy frame.

Number Five

2011-04-29T18:02:00.001+10:00

So construction has started on number five. This is a road racing frame for a friend, Ben. It'll be a 57cm square design, with short 41cm chain stays and a 73 degree seat tube angle. The 72.5 degree head tube and 45mm fork rake will make for a reasonably fast handling bike without being a handful - just the thing for road racing.

Ben wants a nice, stiff bike, so we decided to build with XL tubes - that means a 31.7mm seat tube and top tube, with a 35mm downtube and 36mm head tube. It'll be compatible with 1 1/8" steerers, so getting a fork that fits should be a doddle. I confess I have my doubts about the aesthetics of XL tubes. I prefer the slightly more traditional look of OS tubes myself (28.6mm seat and top, 31.7mm head and down). That said, in a 57cm bike, the XL tubes probably won't look too out of proportion.

Tubeset is Columbus Life, courtesy of Peter at Ceeway. The butt lengths work out quite well for lugs, on account of the frame being a little larger than average. I'm building with Llewellyn Cadenzia XLH lugs, which have a nice classic Bocama style shape. I'll probably do a little lug carving on this one, to make them look just a little skimpier.

Ben uses Shimano parts, so I'll cut the STI bosses off the lower head lug and attach some Llewellyn ones to the downtube.

I really loved using the Llewellyn stainless dropouts last time, so will use the same ones (in a 72 degree angle) for this frame.

I bought some Sachs front derailleur bosses as well, but it looks like (unlike the Silva parts I've used previously, which are amenable to bending to fit different diameter tubes) the Sachs bosses are for 28.6mm downtubes only. A pity, as these are about the sexiest little pieces of metal I've ever laid eyes on.

So far I have all the tubes, the BB (Long Shen), and the miscellaneous bridges and bosses, from Ceeway. I expect the Lugs from Llewellyn any moment, and will start cutting once they arrive.

Silliness

2011-04-12T21:55:00.000+10:00

I'm thinking of doing a bike with fancy lugs - not just the odd heart cutout, but material added to lugs and serious work. The Pacenti style just doesn't do it for me, but the original Malvern Star style most certainly does.

So I'm thinking of making a little fish five star. That resulted in spending the last few evenings slaving over inkscape, creating the perfect Little fish decal in the wonderful Malvern Star style.

Oh, for reference, this is what a real Malvern Star decal looks like. If you've ever seen one in the flesh, you'll appreciate what works of art they are:

Decals

2011-04-08T07:45:00.000+10:00

Can I just say how much of a pain it is getting decals sorted?

I used to make my own - there's a page at littlefishbicycles describing my rather arduous process, involving decal paper for inkjets, decal lacquer, and screenprinting. While I was successful at making a few sets, there was a lot of wastage involved and huge amounts of time.

So for my newer frames, I decided to pony up the dough and get them printed by some of the guys who do this for a living. Kristyn and I set to and designed a really cool decal sheet, shown below:

It takes full advantage of commercial printer's ability to print "4 colour", so we could do nice fades. Rather than just printing "little fish" in comic sans on the downtube, we instead designed a nice graphic version, with block letters, and with a cool shapely S to set it off. Anyway, I reckon it'll look good on a bike.

Only problem is, I sent the files to a couple of decal printers, and they're not interested. They just have too much work on, and they see my little job (rightly) as too fiddly.

So plan b is to go back to spot colour (no fades) and send the artwork to a guy who sells reproductions of classic bike decals on ebay. I redesigned the artwork to suit this process, as shown:

The printer that these decals are targeting is a Gerber edge FX, which at least doesn't involve making screens.

Fingers crossed - hopefully soon I'll have a pile of nice shiny decals to finish my frames off with.

Framebuilding without a jig

2011-04-07T06:16:00.000+10:00

I built my first three frames without the benefit of a jig. It was significantly harder than using a jig, but was still doable.

The secret to jigless framebuilding is to think of supporting each join in position, rather than of supporting the whole frame. Use the lugs to locate the two tubes against one another, and use a simple flat surface (my flat surface was some 40mm square section aluminium tube) to hold things in plane.

My 'jig' was my 40mm square section aluminium extrusion, a handful of pieces of sheet metal of various thicknesses to space things, a long 10mm bolt, and a couple of F-clamps.

Here's the general setup for the first join:

The aluminium section is simply used to hold the head and seat tubes at the necessary angle.

The second join:

Here a spacer is needed, to account for the width of the side of the BB shell. The hole in the extrusion is used to blot the extrusion to the BB face. A large washer is used on the other side.

The third join:

Here the seat tube is joined to the bottom bracket. The extrusion is used to hold the seat tube accurately in plane with the head tube - a thin spacer is needed to account for the difference in tube diameters.

Joins 4 and five:

Here the top tube is added. I keep the extrusion in place to ensure the seat and head tubes stay in plane.

Joins 6 and 7:

This one is hard - you've got to ensure both chainstays are in the right place - I found it easiest to add one stay, then use a known true wheel to locate the second one.

After that, the seat stays are added, and you have a bike.

Auto Air paint

2011-04-05T07:01:00.000+10:00

I painted Kristyn's frame pearl purple. Previous frames have been either solid white or solid red, and painted entirely with Imron two-part paints. As the local place where I buy paint from no longer stocks Imron, I went on a search for something new.

That search led to Auto-Air, which is made for custom car and motorcycle painting. It's about as different a paint as you can get from Imron. It's water based, which is weird, but makes cleanup so much easier.

One of the really neat things about the Auto Air paint is that it's readily available in teeny little 120ml pots. I only used around 60ml to paint kristyn's bike, so a single little pot is all I need. Plus, it comes in a huge array of colours.

The process I followed with Kristyn's bike was to first prime with epoxy primer as usual, then lay a thin coat of white Imron down. I could have used the auto-air white sealer, but I have half a litre of white Imron to hand.

After giving the white base coat a day or so to set up, I then mixed my pearl purple with medium reducer 3:1 (to suit my 0.5mm nozzle airbrush), and sprayed a really thin misting coat. I gave it ten minutes to set up, and sprayed a second, slightly heavier coat. I repeated the process half a dozen times - very thin coats building colour slowly.

The auto-air paint lets you know quite definitely if you're putting it on too thick, by taking on a mottled appearance. It's actually pretty easy to work with, and suits my methodical methods much better than Imron, which always leaves me feeling rushed.

So after leaving the frame to set for another day, I then clear coated it, first with a misting coat, then after twenty minutes putting on a full gloss coat.

The final product looks pretty good. It's still got another couple of coats of clear to go, once I get decals sorted, but in the meantime Kristyn is happily riding it and showing it off to everyone.

Track bikes for smaller riders

2011-04-04T21:09:00.001+10:00

Kristyn is 155cm tall (5'1"). For her first roadie, I designed pretty-much the smallest frame that I could based on standard 700C wheels. This entailed a whole lot of compromises; the head tube angle had to be made rather slack to reduce toe overlap, and the handlebar height, even with no spacers and a -17 degree stem, is only around 30mm below the saddle.

Probably not such a problem for someone of my age, but Kristyn is an athletic 18 year old. I personally like to run 10-11cm of drop between saddle and handlebars, and I'm a hell of a lot older and less flexible than she is.

So for her second frame (a track bike) I'm thinking of using 650C wheels. By using smaller wheels, many of the problems encountered in shoehorning a smaller rider onto 700C wheels simply vanish. For a given toptube length, seat tube angle, and head tube angle, I get about 25mm of extra toe clearance. The minimum bar height is reduced by a clear 50mm, meaning she can get into a really aerodynamic, aggressive position.

So I started doing the design. As I was drafting, it occurred to me that the design is very proportional, effectively a 53cm frame scaled down by a factor of 650/700, or 0.93 times. The only thing that breaks the proportionality is the bottom bracket height, which is set to 27cm to provide reasonable pedal clearance.

The design I came up with is shown above. 74 degree seat tube and 73 degree head tube. 49cm level top tube and 46cm seat tube, with chainstays just 37cm long. If it were a geared bike, such short stays would doubtless play havoc with the chain line, but as it's fixed, all should be fine.

A neat thing about scaling a medium sized 700C design is that most of the lug angles will work without significant manipulation, with the notable exception of the chainstay sockets, which are 68 degrees from the seat tube, so will need a little work.

I imagine it will be plenty quick.

CAD software

2011-04-04T20:57:00.000+10:00

I've previously used AutoCAD for frame design, making use of a copy on my work computer, and logging in via remote desktop etc. That was always a bit of a pain to do.

I contemplated buying my own copy, but balked at the price - for such a straightforward piece of software, they charge like wounded bulls.

Thankfully, now there's a free tol that's able to read AutoCAD .dwg files, and is driven almost exactly the same as my trusty old AutoCAD LT2000. It's called Draftsight, by Dassault systems (who also do Solidworks).

So I've started using that for my frame designs. It runs on windows, mac, and linux. I'll probably put my frame designs up in .dwg format, so you'll be able to view and edit them.

Introduction

2011-04-03T21:39:00.000+10:00

Back when I started framebuilding, blogs were a little too new for my tastes. Instead of writing a blog, I just wrote a web site, using notepad to write html. It's at http://www.littlefishbicycles.com/. So now blogging tools seem to be a whole lot more advanced, making the effort involved with writing html, formatting images, and publishing seem rather silly.

Thus, I thought I'd try blogging instead, as a simpler way of sharing thoughts and ideas.

So since my original webpage was written, I've moved house and gotten back into framebuilding. I'm mostly done building a road race bike for Kristyn (pictured above), and have a few more frames in various stages of contemplation:

A road race frame for myself, using Columbus Genius oversize tubing, and either Henry James or Llewellyn lugs.
A track bike for Kristyn, probably based around 650C wheels, to better accommodate her shorter stature and allow for a decent drop from saddle to bars.
A track bike for myself.
A road racing bike for a friend, who's a little over 6' tall. This will probably be built using Columbus Life OOS tubes, using either fillet brazing or Llewellyn lugs.

Depending on how the 650C track bike design goes, I might do a 650C road racing frame for Kristyn as well.

Anyway, that's the plan. I'm still working in steel, and still doing classic lugged frames. I'll do separate posts for each of the frames, as the designs progress.