With every frame I have built, I have thought that I really need to make a chainstay and seatstay mitering fixture. And every frame I file the miters in and it just sucks! I’m doing this like a caveman. Like using a rotary phone while someone sits in front of me on their smartphone.
Naturally, I was going to make my own! I scoured Google Images for stay fixtures that I liked, I probably have a hundred screenshots on my phone in an album. There has never been a stay fixture that I was really psyched on building. But over time I settled on a design in my head. One day while it was cold as shit here in MPLS, I finally decided to start turning my ideas into pixels. My #1 goal was to be able to miter BOTH ends of chainstays AND seatstays all in one fixture! (Not at the same time. Haha!)
I decided to use a 1530 extrusion from 80/20 for the main beam of the fixture. This provides a wide base that’s rigid enough to support the tube blocks. Then I needed to make the dropout side of the fixture height adjustable to handle the tapered tubes of the stays. So I whipped up a simple bracket with a platform that raises and lowers on a slot with two pins as a guide. This platform holds tube blocks. I added markers to reference the distance from center so it would be easier to set up the stay ends evenly.
The BB and ST side uses similar tube blocks and has a fixed height block with similar reference markers. Of course I had to add “Varco Cycles” somewhere. 😁
Ok, cool! Time to machine it!
Here is the unverified version. (I still need to try it out) I’ll be building a completely fillet brazed fat bike soon and using this fixture. But first I’ll most likely lend it to a friend who is about to do a short production run to test out. If you have any suggestions PLEASE let me know! You can leave a comment here or on FB/IG, email me (firstname.lastname@example.org) …. however we communicate weather we know each other or not. I’ve already gotten a couple of great suggestions for improvement so thank you to those folks!
I added a couple things based on the recommendations from seasoned builders.
If you’re a machinist and you haven’t machined the word “FUCK” into something, are you really a machinist?
I’ll certainly update this when it actually cuts tubes! Quite excited to finally see the reality of this fixture!
Until then, have fun!