I am working on the chain stays of my first frame. I have replaced chain stays on other bikes in the past and this has challenged me.
I am looking for advice on how to keep the oval part of the stay in a vertical plane and symmetric side to side. The oval is too rounded for an angle meter to attach to. I can eyeball the fit but would like a better way.
Update: Thanks for the great input! I was able to print Phase blocks and use aluminum extrusion supports to get the stays phased and level. This was incredible for S-bend seat stays. The rear end of this frame turned out way better than I expected!
It’s tough to answer well without knowing you process. Are you using bikecad and templates or a tube notcher to make your miters?
If you can lay everything out square and scribe a centerline, that should help keep the stays in phase. buying some appropriate oval tube blocks from alex meade might be beneficial if you’re working with basic tools and plan to do this again.
Check out post 22 from this thread. @Mikesbikester came up with a pretty brilliant jig for the stays. Looks like he used it for mitering, but if you have some 3d modeling chops and a 3d printer, something similar may work here.
I am mitering by hand. I have the free version of Bike cad with a 1:1 drawing. I have been thinking about 3D printing phase blocks for these stays. I do not want to purchase any because I do not plan on using these stays again.
I am using the Chop Source fixture so I can square off the base of the fixture.
It may be pretty easy to print a template for hand mitering your stays like I did for the seat tube notch on my chainstays in that post. Especially if you have solid works and a printer, and can come up with a good way to orient the template. ultimately isn’t a whole lot different than a paper template but it can be handy. If you need a hand with SW surfacing (it’s a little weird to use if you haven’t already) I’m happy to hop on a call or something if you need!
Thanks for all the input! This is what I came up with my fixture and it would double as a support for seat stays. I will update with lessons learned and see where the design ends up.
Thanks! I printed the template for the seat tube to BB and it worked great. I didn’t need them for the top and down tubes. I will look into this once a get to build with the chain stays I plan on using more often. I had to use these due to availability issues.
In the past I have mitered one stay and used it to create a template to transfer over.
