Posted: May 6, 2013 Filed under: Uncategorized
The approach to the island workshop, a 1920s boatyard built for repairing Thames lighter vessels. The boat moorings here are tidal.
I decided to set myself up in a workshop nearer to my brazing job at the Brompton bicycle factory. The building is an old boatyard on a small island on the tidal Thames in west London.
Original heavy machinery still features on the island.
My unit – compact, but everything I need in an inspiring setting.
Still some organising to do, but it’s taking shape.
The cockpit – I really like the atmosphere here – skilled yet modest craftsmen come and go in the building and the light and changing tides alter the feeling of the place daily.
Finding a place for everything took time but it’ll pay off.
I thought it was about time that I bought myself a decent torch.
I bought this old Harris 19-2 torch set on ebay the moment I saw it.
Decades old, but never been lit. Even has a cutting head. I am based at a working boatyard, so you never know, I may find a use for it.
I found some reverse flow check valves for it too. Obviously I’m already using flashback arrestors.
Harris is a US company, but my torch is made in Italy under licence as “Harris Europa”. It’s really nice to use and very quiet.
In my day job as a production brazer at Brompton, we use injector-type torches which are great for use with gas fluxers as they really help to push the braze forward and shape the beads with their added thrust. I believe that my Harris torch here is what is known as an “equal pressure” torch, which gives a slightly gentler flame that’s easy to control and should be good for making smooth concave fillets.
I’ve also decided to restore an old Honda CD200 motorbike as a project so that my commute to the bike factory and errands to and from the workshop might be more practical. Sorry if this appears off-topic, but I was without a workshop and a torch for a good few months..
The countershaft was worn where the front sprocket mounts, so I thought I’d rebuild the engine and replace any other worn parts, seals, piston rings, etc.
Worn shaft (top) and replacement.
Now to transfer the gears..
Laying all the bits out – checking against a diagram is important.
Rebuilt gearbox put back together in the crankcase half.
Top view with gasket in place.
The swingarm on the bike was pretty rusty – after shotblasting it looked pretty sketchy so I cut away some steel to reveal the extent of it all. I found a big hole in the tubing inside:
Didn’t fancy riding this too far..
I found it impossible to find a replacement swingarm that was in good condition, and so I bought a used but rust-free US CM200 Twinstar swingarm which is very similar, but I’d have to swap over the driveside fork end (my bike has a bigger spindle to mount a cush drive) and a few other small mounts for the chainguard, etc.
I also decided to remake one of the welded-on plates as the rustworm had made it pretty flimsy:
Marking out the template in new steel.
Then I drilled inside the lines on the drill press.
And cut and filed it to shape.
I brazed it all together with my ace new torch.
I soaked the flux off in a bucket of water.
seemed to go pretty well.
Alignment was good enough.
The finished swingarm. It’ll be powdercoated with the frame and then I’ll push new pivot bushes in.
I promise my next post will be purely pushbike related!
Bye for now,
Posted: June 17, 2012 Filed under: Uncategorized
My uncle got in touch with me to ask if I’d build a tricycle for my auntie as a surprise birthday present. It would have to be able to cope with a gravelly farm track in South Wales, be a step-through frame design, and be 2-wheel drive. Er, yeah, no problem..
80mm rake gives this trike around 20mm of trail.
Bolt-on axle housing from an ebay donor trike. It’s one-wheel-drive at this point.
I needed an alignment shaft to keep all bearings within a tolerance of 0.75mm of misalignment. Gulp..
Sandblasted axle housing with alignment shaft fitted. Bearing shells are right-threaded English BB size.
I had some fun aligning this frame, I can tell you. Perhaps a little ambitious for my 4th frame, but I got her made on time, just.
I found a Rogers bolt-on bike-to-trike axle housing, and had a 2 wheel drive cassette & axle made for it by Geoff Booker at Trykit. The Trykit axle and custom cassette body is a lovely bit of kit. I removed the bolt-on tabs from the axle housing, moved the derailleur hanger boss and brazed the housing onto the chainstays with 4 dummy bearings that my friend John Discombe made for me. A cold-drawn 18mm rod was placed through the slip-fit dummy bearings to keep everything aligned during (and after) brazing. The drive-side chainstay had to be bent to clear the cassette housing.
I used a flat surface with marked lines for centrelines, axle lines & BB lines (using another round bar on V blocks & dummy BB cups), and I also used a surface gauge and engineers squares. A digital protractor kept the seat tube at the right angle, and these adjustable V blocks were handy for levelling the rear axle alignment bar and to get the right BB drop:
I’ve got balls. Have you?
I used a ladies’ lugset that couldn’t really give the angles I needed, so I ended up fillet brazing the hockey stick, and I ran into trouble with seatstay heel strike (trikes usually have mega-low BB drops as they can’t lean and the lower C of G is beneficial to handling, and I had unwisely opted for a lugged BB shell that limited my angles), so I built tabs off the rear axle housing to bring the seat stays way back. I drilled the hell out of the tabs to try and save a little weight. For a lot of the build I kept the chainset, a pedal and a shoe cleated-in just to be safe with heel clearance on the drive side.
It was fun to ride.
Trikes always tend to follow the camber of the road, so low trail is preferred to minimise the effort needed for constant steering input. Seat stays are regular bike stays but used upside-down (thin end at the top).
Cross tyres were chosen for the loose gravel surface it would be ridden on in Wales.
I used 700c rims because the rear hubs that I salvaged from the ebay junker donor trike wheels had very small flanges with spokes that were already elbow-to head (they came with 26 x 1 1/4 rims – This is England!)
She’s now in Pembrokeshire, South Wales, and I’m told that everyone wants a go..
Also, I’m getting well stuck-in to production brazing at the Brompton Bicycle factory, and, way off-topic, but I was roped into playing bass in my mate’s “music video” about a fictional darts-playing character. I’m sorry:
Bye for now,
Posted: March 28, 2012 Filed under: Uncategorized
At the UK Handmade Bike Show, Bespoked, I won the Best New Builder award for my “Wilkinson Mixed Gear” bike:
Photo by Kayti Peschke.
Here are some more pictures I took of my bike:
Polished stainless front mech band – protects paint and looks cleaner when removed for singlespeed mode.
My “Wilkinson Mixed Gear” dropouts.
Mudguard extension tube allows for a more rearward wheel in tour mode.
The Wilkinson Wheel Carrier – compatible with lawyer tabs!
Removable shifter bosses pass through a stainless tube brazed inside the downtube.
Here’s an article listing the winning bikes in all the categories: http://road.cc/content/news/55706-bespoked-bristol-robin-mather-wins-best-show-plus-prizes-feathers-rapha-collab
My girlfriend Saga for all her help, without which I’d have had a nervous breakdown.
Dan Hamilton – for the CAD drawings for my dropouts.
John Discombe – for all the help with the jigs so I could make my dropouts.
Peter Flynn – for doing a great job with the paint.
Ryan McCaig - for letting me borrow the odd tool and sharing the acetylene.
Dan Fennings – for doing the CAD for the wheel carriers.
Tamsin – for commissioning Wilko 3 and coming up to the Bristol show.
My mum – for lending me the car.
Mike Salmon – for putting us up in Bristol and making us feel at home.
Sarah and James at Brixton Cycles – for letting me use the headset tools.
Peter at Ceeway for sponsoring the prize of a frame tube set.
Columbus for sponsoring the other prize of a carbon fork.
And everyone who came up and chatted, prodded the bike or squeezed the tyres. It was a great show.
Bye for now.
Posted: March 10, 2012 Filed under: Uncategorized
So I have to get this bike frame built and to the painters asap to be ready to build up and photographed before Bespoked. There’s no time to lose..
..Better whip out my Herbie Helm lug vice. Stainless, of course.
Checking my hand-filed mitres. Hmm.
New lug and filed lug. Pointy. These can hurt you if you're not careful. Ask Ryan at Oak Cycles.
I wheeled out the Wilkinson "Abominator" jig. I made this in my kitchen a couple of years ago. The swivel vice has a V-groove and I got it from Axminster. I must upgrade soon. Donations welcome.
Silver brazed headtube/downtube. I used Cycle Design's "Stainless Light" flux. It comes off easily with water.
The story so far..
Internal cable routing. How hard can it be?
Some eight hours later, after making sure the internal brass guide didn't touch the tube wall, rattle or kink, I got it all brazed up.
It was rewarding when I got it done.
Lining up everything with the drawing.
Ok, I own up. I made a mistake. When I was planning the cable run I looked at an American bike in the workshop and a German road bike at my house. Brake levers on wrong side. Whoops. What a wally. I had offset the internal cable entry and exit to suit a right hand rear brake lever. Remember that the cables should cross in front of the head tube to give a decent run. So… in keeping with the concept of this bike, and in order to partially conceal the cable entry point, I put it underneath the top tube at the front. This gave me a better cable run and a side-exit to the rear caliper on the correct side. A serendipitous event, no less. Hoorah!
The top head lug needed to be blacksmithed to conform to the tube. I tapped it with a small brass drift made from a bathroom door sliding bolt lock, after squeezing it in a tubing block.
And I also had to file the point shorter on the lug, as it was overlapping the first lug's point. A peril of short head tubes.
Now it fits.
Checking the fit in the lug.
Testing the fit on the tube.
Grinding out the chainstay sockets in the BB shell.
My belt and braces approach to dropout alignment.
Cleaning out a chainstay so the brass will take to it.
Fluxed and brazed with brass. Lots of cleaning up to do here.
Time to silver braze a gear cable stop onto the chainstay too.
After soaking the flux off under the tap.
I decided to put the chainstays in on Ryan's frame jig. The stainless band on the seat tube will stay unpainted for a 31.8mm front band-on mech that won't leave damaged paint to be visible in fixed gear mode.
I ran a cord from the dummy axle to the BB to double-check the seat tube/chainstay angle with a protractor.
Using my angle-finder.
I brazed the tops in the jig, then finished in the Park stand.
Next I drilled holes for the bottle bosses. I had to enlarge them slightly with a round file.
I had to improvise a way to hold the diamond reinforcement while I increased the hole diameter.
I tried to resist the temptation to add that little bit more silver just to "make sure", but it gets me every time.
Let's check the rear spacing..
And the left alignment.
..Matches the right alignment according to the Park FAG-2 tool.
Rear wheel looks fairly centred. I built and dished the wheel myself so I know the rim is centred.
Same goes for the fixed rear wheel.
The H-Tools say yes!
Time to use the piece of extruded aluminium I tapped and put an M5 threaded probe through. Use it like the FAG-2 tool but touch the 3rd contact on the wheel rim, not the dropout. This shows that the dropouts are level, and one is not higher than the other.
After pulling the stays around, the other side matches. A perfectly dished wheel is essential for this. This is used before the seatstays are attached. I checked the resulting angle of the chainstays against my drawing to make sure my geometry would stay as expected.
Getting the brake bridge right. A mudguard has to fit in there too. I have only tacked it in here. I got it in the perfect position eventually, and almost straight.
Note to self: procure something more fireproof to shield the drawing whilst tacking. Although we have a cast iron surface plate in the workshop, I tacked the frame tubes on shimmed V-blocks on top of my drawing, which was on top of a sheet of 12mm toughened glass.
I’ve now taken the frame and fork to the painter. Tamsin my customer has chosen a very vibrant green. You have been warned..
See you soon.
Posted: March 4, 2012 Filed under: Uncategorized
I’ve made some progress with my 3rd frame build. Here are the pictures:
These are my fork ends. I'm going to cut the rack mounts off them but keep the mudguard mounts. One is done already in this picture.
Filing them smooth after cutting.
Bending my fork blades in the bender I made. Not 100% happy with the curve I get, but it's not too bad.
Checking the fork rake against my home-made gauge. I want 43mm of rake. There are lines to centre the blade so it's straight.
Cutting the blades to length.
Finding the straightest side of the seat tube. The worst side will be used in the fore and aft plane of the frame to minimise lateral misalignment.
My seat tube is brazed into the bottom bracket shell after tacking and checking alignment.
Oh yeah, and they let me try out brazing a bottom bracket assembly at work a few weeks back - here it is (it was rejected)... Come off it, it was my first one!
Here's my fork held in the Wilk-O-Matic SPX-3000 De-luxe laminate construction steel-reinforced fork jig that I made in my kitchen 3 years ago. My workshop mate Ryan's just bought a proper fork jig so perhaps if I ask nicely next time I can use that..
The bits 'n' bobs so far.. The top tube will have internal cable routing.
After brazing in the fork legs. The flux got a little tired and began to darken after I chased around the shorlelines with the flame, but I'm confident that I didn't overheat the joints as the steel didn't go red. It cleaned up nicely.
I’ve done quite a bit more on the frame at the time I upload this, so there are more pictures to come when I take my camera to the workshop.
Posted: February 16, 2012 Filed under: Uncategorized
Ok, So I need a jig to tack my seat tube into the bottom bracket shell.
I had all these bits..
I found all this stuff down the back of the sofa..
Then I said the magic words, “jiggy-wiggy-wamma-jamma”.
And the Wilk-O-Matic ST1 jig was born.
Complete with Park stand clampability.
Nearly got this one in focus..
An adjustable parallel is used to shim up to the height of the seat tube just as it exits the BB shell. The base is a precision straight edge. I had this side of it clocked at work at less than 0.1mm error over 1 metre.
The screws lock the adjustable parallel at this height. I had to make sure the tube was sitting flat on the top of it.
Then I moved the parallel to the other end of the tube and insert it into the slot I cut to allow it to sit on the flat surface. I close the toggle clamp after adjusting its set screw and locknut to give the correct downward force and travel.
Detail of angle bracket with brazed reinforcements. I stuck some cushioning clear rubber, the type you use to protect bike frames from cable friction or chain rub, underneath the bracket to protect the flat surface. It's self-adhesive and stuck to the bracket.
I had just enough room to double-check along the top with my surface gauge.
Both ends matched for height.
I made these rectangular washers out of some 3mm stainless bar so they would sit in the gap and raise the nut above the flat surface, thus protecting it. I filed the edges off to leave them slightly rounded.
At the other end I made a double washer with 2 holes for the bracket bolts.
All in all, I’m happy with the jig, but I have to be careful not to drop the adjustable parallel on the concrete floor. Perhaps I can improve the design in this respect.
I brazed my fork crown to the steerer today.
I took this shot while filing away the excess steerer tube and silver.
I cleaned up the crown and filed the points to be crisp and sharp.
Next I mitred the seat tube with a half-round second cut file.
My tubing blocks came in handy.
Checking the mitre against the BB shell. The "ears" need to come down a bit.
View through the down tube socket. I've filed the points and the edges of the socket walls to sit at 90 degrees to the tube.
Good old John milled my dropout faces down by 1mm and gave them a near-mirror finish. Then it snowed.
Now the track faces are nice and shiny. I've cleaned up the brass and started to shape the edges to more rounded chamfers since these pictures were taken.
I had to show off the Winter Viburnam.
Plenty more to come. Bye for now.
Posted: January 22, 2012 Filed under: Uncategorized
My tubeset has arrived from Reynolds and I’m ready to draw the frame design. I plan to use 650c wheels as they will allow a little more room for mudguards on this smaller frame size, whilst still being able to take fast 23mm tyres for zipping around town as a fixed wheel bike. The rims can take up to 28mm wide tyres if so desired in “tour mode”.
This bike is for my friend Tamsin, and I hope to show it off in the new builders’ room at Bespoked, the UK hand built bicycle show in March.
Following on from my last post I have to allow some more clearance for the rear quick release nut to pass the derailleur pivot so that the rear wheel could drop out cleanly.
Here are some pictures of how I achieved this:
I marked the dropout with a marker pen so that when I marked the required clearance around the nut and derailleur, my scribed lines would be easier to see.
I then scribed a line to round off the inside corner.
I had to file carefully in the vice to avoid nicking the other surfaces.
I tried to get a smooth curve.
Checking to see if it will pass - the nut I used here is quite large, over 19mm. I thought it would be best to check the fit with the "worst case scenario" size.
The 1st drive side dropout became a template for the non-driveside dropouts, and vice-versa, with flat plate against flat plate. I scribed a line tracing the corner.
the line is marked.
Marking up a batch to be filed.
Before (top) and after (bottom). I'll clean up the stray brass a little and try and remove that broken bolt in the rack mount. Never use a blunt tap.. I bought a much higher quality tap to finish all the other threads properly.
Filing in the vice to the template dropout.
Almost matching now.
Will she pass? Yes!
I filed the inside of the track ends flat and parallel, smoothing out any lumpy brass. I used a round file in the curve.
On a few of the dropouts I cheated and touched in a little brass from inside if there were any small gaps (come on, I am a newbie). This obviously had to be cleaned up with files too.
A flock of filed dropouts.
Still to come: Machining the track end faces, chamfering the edges smoothly, deciding on head tube angle and fork rake to give the best trail figure for both uses and mudguard issues…
Bye for now,
Posted: January 13, 2012 Filed under: Uncategorized
Following on from my previous post, I’ve been back down to the workshop to do some more work on my dual-use dropouts that I designed to accept 120mm hub fixed wheels or 130mm cassette geared wheels with a derailleur.
Here’s a peek at what I’ve been up to:
Tapping M5 threads for the rack & mudguard mounts.
After tapping all the threads with cutting oil in the drill press chuck, I got pretty grubby!
I then had to degrease, wash and dry the dropouts ready for brazing.
I dried them with paper towels after using detergent and warm water to remove the degreaser.
I sanded the mating faces so the brass would take as well as I hoped it would.
Pre-braze cleanup completed.
I took this opportunity to file off the marks from the waterjet cutting process, as it would be much more difficult after brazing.
..It took a while..
I took a 2mm drill and cleaned out all the abrasive paper debris from the pin holes by hand.
Next, I fluxed up all the dropouts with Tenacity 125 flux, the same stuff they use in the autobrazers at work. I added some more after this photo was taken.
My NASA-grade Wilkinson FX497DBJ dropout brazing jig is set up in the vice. This hi-tech model allows all-round flame access.
I tacked the ends first to try and eliminate lifting of the track faces. This was about midnight.
Moving the flame around the dropout.
It was a little challenging to control the heat whilst looking for the brass to flow all the way through.
I moved the torch around underneath to try and spread the heat evenly.
My workshop-mate Ryan took these pictures. That's his torch and glasses too. Should've remembered that dust masks don't work with tinted glasses - some of your breath is channeled up around the sides of your nose and steams them up. At least in London in January it does.
It took some time to braze 12 of these..
..But I seemed to get better at it as I went along.
Filing the track slot flat and square after brazing.
I decided to get the dropouts shotblasted as the flux is not water soluble and there was a little blackening here and there.
Trial-fit to my road bike wheel.
I discovered a small obstacle, being that the quick release nut will not quite slide past the derailleur mounting bolt/pivot when removing the wheel. This isn’t as bad as it sounds, as there is plenty of metal that can be filed away so that the axle and nut can come forward a touch at the bottom of the vertical dropout slot. I basically just need to round the corner off like this:
I need to carefully file a new curve profile something like this so that the nut can pass the derailleur mount. A bit of weight loss won't hurt..
At least I didn’t order a thousand investment-cast pairs with this issue. Wilkinson Cycles is constantly striving towards improved design by research and development!
I also intend to chamfer the edges of the dropouts to a rounded curve by filing them. Laborious? Yes, but also very rewarding. I’ll get the track faces surface milled to make them exactly parallel to the back plates and exactly 5mm proud of the main droupout body.
I placed my tubing order with Reynolds today. Here we go.
Bye for now.
Posted: December 31, 2011 Filed under: Uncategorized
When I told my Grandma I worked in a folding bike factory, she sent me these pictures of my Great Great Uncle George in about 1914. I think he was in the Hertfordshire Regiment. Note the handy rifle carrier.
Great Great Uncle George
George and chum with bike folded on his back.
While on the subject of folding bicycles, I thought you might like to know that I’m progressing fairly well with my production brazing training at the Brompton factory in Brentford, having learned 5 parts out of about 15 that make up the total brazing repertoire. The 14-mile fixed wheel commute to Brentford at 5.30am has driven me to learn to ride a motorcycle. Don’t worry, I haven’t forsaken the True Way of pedal power, although I feel jubilant about passing my motorcycle theory test yesterday.
Today I was in the workshop making my “mixed gear” dual purpose dropouts. The idea is that they are fitted to a single speed frame of around 73 degrees head tube, 73 degrees seat tube and shortish chainstays. Most of the time the bike is used as an urban hack city ride with a 120mm oln rear hub except, now and then, the owner, who may not want the expense or clutter of two bikes, can fit a 130mm rear road wheel with a cassette and derailleur, some kind of shifters are added, and, as the wheel sits further back in the dropout and higher up, you get a “relaxation” of about a degree in the head tube and seat tube, and also a longer effective chainstay length, with the accompanying increased stability complimenting the provision for a rack and a mudguard. The BB height would drop a tad too. Now you have a light tourer to head out of the city on a few times a year; you just need a spare rear wheel, derailleur & shifters, rather than a touring bike gathering dust and clogging up the hallway in your bohemian shared house in London’s up-and-coming Hackney.
This is the idea. Some people think the idea is crazy. Some think it’s interesting. I hope I worked everything out properly and that the chain doesn’t get fouled on the “track face”. Oh well, nothing ventured and all that. It will certainly be a challenge.
All-round diamond geezer Dan Hamilton helped me get from my scribbled pictures to CAD files:
Early sketches.. will they work?
The design was simplified to be waterjet cut in the end, with 1mm faces abandoned.
Dan helped me with CAD. A nice guy.
Next I got the parts 3D printed in plastic.
It gave me a clearer picture of what I would get.
I got 10 pairs waterjet cut, with 20 accompanying track end face "extrusions". 9 pairs to ruin? and possibly 1 pair to realise I measured incorrectly? We'll find out..
I looked into getting the parts CNC milled in one piece, but had trouble getting a decent price as I was told that a special jig would be costly to make. I thought the brazing way might be fun too.
I had the parts waterjet cut and then my engineer friend John kindly made me a little jig with drilling guides to enable me to pin the parts in place while I braze them together with brass (I originally thought I’d mill a seat for the track faces to sit in squarely, but John came up trumps with the pinning method). I chose to use brass as it’s less likely to remelt than silver if I decided to braze them into stays with brass. Besides, I’m learning the secrets of brass at Brompton, so I have no excuses now.
Here are some pictures:
Drilling the pinholes using the drilling guide jig.
The drill press chuck wouldn't go down to 2mm so I had to add this second chuck.
John made me this neat little pin holder. 4mm lengths can be cut cleanly with a junior hacksaw, and filed if necessary.
A great way to recycle knackered old 2mm spokes. You can hold it in a vice.
A perfect little pin is made.
Jigging up a dropout plate. The hex key locks it in place.
Holes are drilled to about 2mm with the drilling guide holes in the jig. I marked the inboard sides with an X to avoid mistakes.
Then the track end "faces" are drilled to match. They will decrease the OLN by 5mm per side to accept a track hub.
In the jig.
The two parts can now be lined up for brazing.
Pins in place.
Bobs yer Muvva's Bruvva.
One pair done..
The track faces will be milled down to be exactly 5mm proud of the dropout plates:
A. Because I originally intended to seat them 1mm into a milled trench, therefore their 6mm starting thickness would be correct, and as I have now pinned them, they will be 1mm too high.
B. Because the brazing may cause them to lift and/or distort.
Next, I had to tap a 10 x 1 thread in the derailleur hanger. I did this with some help from the drill press:
I knew those old G-clamps would come in handy one day..
I had to line up the dropout very carefully and lock the table.
I turned the chuck by hand with the key in the chuck for added leverage. I was ably assisted by my wonderful girlfriend applying steady light pressure on the drill press handle.
After backing out of the threads. I used plenty of cutting oil.
Looks like I cut these threads squarely.
I’m going to try and blog this frame build as best I can. Bye for now.
Posted: October 22, 2011 Filed under: Uncategorized
The other week I remembered that I still had my undeveloped super-8 film in the fridge – it had been there since April 2009.
There are a couple of shots of my first frame taken in my back yard.
I got it developed and put some music to it:
Oh yeah, and you can read my finished frame building report here: