Chainstays replacement
 

Haven't posted here in ages. I'm doing a repair on one of my frames so I'll show what I'm doing.

I built this frame ~15 years ago. Somewhere along the way the chainstays got crushed by the kickstand via the support plate. Not sure how that happened. I noticed the dents last year but this time I saw a crack. I chopped the plate, unbrazed the stubs, cleaned up and saw two cracks on each stays. Ouch. They have to go.

https://cimg6.ibsrv.net/gimg/bikefor...957867ea19.jpg
https://cimg7.ibsrv.net/gimg/bikefor...e0b6d183ef.jpg
https://cimg9.ibsrv.net/gimg/bikefor...cb9d39c85e.jpg

Some residual strain but not too much. I unbrazed the dropout sides and cut the chainstay stubs into quarters using a mini hacksaw. Use the cut outside the lug as a guide. You'll feel the saw glide when you hit the brass line.

https://cimg0.ibsrv.net/gimg/bikefor...72f065fb04.jpg
https://cimg1.ibsrv.net/gimg/bikefor...853e0eb344.jpg

Next is the unbrazing. I used some pliers to wiggle out the sections out one by one. Removing them becomes easier after the second. Some broke off inside; one piece just wouldn't come out. More work for the file.

https://cimg3.ibsrv.net/gimg/bikefor...4c2dfa0d57.jpg
The graveyard.

https://cimg4.ibsrv.net/gimg/bikefor...feb1b47b17.jpg

Ouch! I've attached a few K stand mounting plates (just did one for my city bike yet to be painted) and one thing I do is to braze on an axle spacer onto the plate where the mounting bolt hole is. This allows the K stand to be very tightly clamped but have none of that force acting on the stays. There's no top plate and with a tall enough spacer access to the bolt head is still good. The other thing I do is to braze on little posts that will cradle the K stand body and prevent it from rotating (due to the swing of the leg). Glad to see you fixing up the bike. Andy.

Pictures? I think I can imagine what you describe but pictures would be awesome!

Here are two shots of my K stand positioning/mounting methods.

First is from way back in the later 1980s and on my alloy shelled SA AW city bike. I used just the locating studs/nail heads. I figured that most of the issue with K stands is with single legged types the leg produces a swinging/rotating force on the head and mounting hardware. This causes the mounting bolt to loosen bit by bit. The usual "solution" is to tighten the mounting bolt REALLY tight, leading to dented stays on nice thin walled tubing (and on gas pipe stuff too if done way too much). My solution borrowed from the common mounting plates that have a couple of bent tabs which help prevent K stand movement, if the tabs actually contact the top's body (which isn't the case often enough). I wanted to have the tabs (or in my case the pegs) be slightly closer together then a slip in fit allowed and I filed little grooves along the sides of the top which let the top slide down onto the stay and have no ability to twist about. This let the top plate on the top of the stays to not have to be that REALLY tight mounting bolt requirement. BTW this frame used both socketed joints and fillet. I added bronze to the ends of the sockets (BB shell and crown) and filed the transition smooth to mimic the fillet joints elsewhere. An interesting aesthetic but not to my liking any more.

https://cimg0.ibsrv.net/gimg/bikefor...2dae804d7c.jpg



This design works very well but I wanted to loose the top plate entirely. So I added a plate to the mess as shown here on my most recent build (to replace that first city bike, which I would love to move onto someone who respects SA AW's and hand built stuff, like the directly brazed onto the frame self made rear rack).
https://cimg0.ibsrv.net/gimg/bikefor...f783487462.jpg
You can just barely see the inside of the mounting bolt spacer, a crescent of light at the end of that "tunnel". Also showing is the two holes in the BB shell underside. One is threaded (bottle boss inserted and lip filed down smooth) for the cable guide and the other for draining water out.

Both of these frames are waiting for the completing of a paint booth to do the spraying in. That is a whole 'nother thread and one I'll post about after I have something shinny to show:) Andy.