Friday, 29 April 2011

Decals continued

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

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.

Tuesday, 12 April 2011


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:

Friday, 8 April 2011


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.

Thursday, 7 April 2011

Framebuilding without a jig

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.

Tuesday, 5 April 2011

Auto Air paint

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.

Monday, 4 April 2011

Track bikes for smaller riders

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

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.

Sunday, 3 April 2011


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 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.