Monday, 29 August 2011

More progress on Keith's frame

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:

Sunday, 28 August 2011

Keith Anderson dropouts

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.

Monday, 22 August 2011

Fear me!

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

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.

Thursday, 18 August 2011

Progress on Keith's frame

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.

Wednesday, 17 August 2011


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.

Thursday, 11 August 2011

No Girls Allowed!

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?

Saturday, 6 August 2011

The Sydney framebuilding underground.

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.