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Old 02-10-21, 11:24 AM
  #419  
guy153
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Join Date: Dec 2019
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Go anywhere gravel adventure trekking soft-roader build

This was basically a frame replacement for a 1990s Claude Butler MTB I owned since new. It had a bit of a ripple in the downtube, and every other component except the front shifter (which is actually broken, I had forgotten!), the stem, the handlebar, and the brakes had been replaced. But apart from that it's the same Claude Butler. The old frame was lugged and labelled "Reynolds CrMo". No mention was made of butting. So I think it must have been plain gauge. And rather heavy-- the new one plus fork is 1.2kg lighter than the old one was at 2250g frame plus 860g fork.






I might shorten those rear fender stays a bit...

I actually converted the original stem to threadless (there's another thread about that in the Framebuilder's forum) and then found I was also missing a cantilever hanger, so made one out of some 3mm plate. I drilled a hole in the plate with a 28mm hole saw. My holesawing always cuts a bit bigger than it's supposed to anyway so after a very small amount of filing it fit a 28.6 steerer very well. Then I cut and ground it into shape and put the two bends in by cutting about half-way through, bending, welding it up again, and sanding down the welds. I then TIG brazed on a cable stop:



The seatstays were interesting. I usually mitre them straight into the back of the ST and weld them on. I started with some Zona single-bend SS which I've used before, and which fit very well that time. But this is a bigger frame and they were so much longer that there was lots of tube after the bend and they ended up much too far apart, as if for a fat bike. So then I thought maybe I could make a wishbone rear end to make them effectively shorter, and it sort of worked, but they were still too far apart. So then I gave up and got some straight Reynolds 525 stays. Ideally one would add a bend, but I found that if I just attached them to the sides the spacing was just right for the canti bosses:



I cut both stays at 45 degrees with a chop saw and TIG welded caps made of 1.6mm mild steel on and then sanded it nice and smooth. They're welded at the bottom but I TIG brazed them to the ST using silicon bronze and made a nice big fillet all the way around. Instead of trying to file it in that tight spot I just smoothed it out with a little bit of car body filler, and also added some around the front for a smooth effect. There's no actual braze under that front section just a real TIG weld right at the bottom and then filler

All the tiddly bits are also TIG brazed on, including the seatpost binder, which I made on my minilathe. But the canti bosses are all welded (although brazing would have been fine).



The paint is spray.bike with 2K clear on top. We'll see how it holds up! I've only ridden it just up and down the road but it feels really nice, very stable perhaps because of the 71 degree head angle. The old front derailleur was completely seized so I got a new one, and I also had to get one new canti as I had enough non-knackered parts from the original two to reconstruct one. But now it looks like neither shifter works very well so I'll have to get some more. I guess might as well convert to 9 speed while I'm at it. Gotta keep up with the latest developments in technology after all.

The pink is "Strawberry Hill" which I've used before and looks really nice in real life. The purple is "Plumstead" which looks a bit like red bean soup. The original bike was a lighter mauve all over so I wanted similar colours.

The tubing is "single oversize" I think it's called: 1 1/8" TT and ST and 1 1/4" DT. The tubes are all .8/.5/.8 except the DT which is .9/.6/.9 because Reynolds sent me the wrong tube by mistake. But I think .9/.6/.9 is actually a good choice. Main triangle is 631 and stays are 525. The HT is actually 853 because they'd run out of 631 HTs. 73 seat, 71 head, 70mm BB drop and 438mm chainstay. 4 degree TT rather than horizontal as a homage to Paul Brodie who, according to the internet, invented the sloping TT and whom we all now love watching on YouTube.

Really pleased with how it turned out and can't wait to get the gears sorted out and go for a proper ride!
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