# Chainstay fixutre DIY



## Brad Bedell (Apr 18, 2009)

This is how it is currently:









I found the side guide blocks on the axle wasn't long enough for the slotting. 









First of all, thanks to Walt for answering all my pesky questions offline! Thanks to everyone who has photos of their tooling up on the web so that I could be inspired to build this piece. I suppose I should also thank Walt for a fun bike that has motivated me to dust my old 'when I get aroundtoit' garage projects off.

I've been talking about doing tooling for myself about 3 years now. After I built my first frame, I swore to not do it again without some decent fixtures. I know it can be done, but I have about 10 points of patience. If I burn up 8 of those points with filing/fitting and holding tubes together to tack weld, lets just say that I get anxious and say 'it's good enough'. Despite the number of times I've learned that lesson, I'm never happy with 'good enough'...

Anyhow, enough about me. I still have a few more things to do to it once my drill press and cross slide are reassembled. I got tired of sloppy tooling and decided to fix it... Though, even with angular contact bearings as an upgrade to the radial bearings, I suspect I'll buy a proper metal drill press before my frame jig is finished...

Things still left to do: 

guides for the side of the 8020 stick to keep the axle at a right angle. 
Build a stand off for the clamp 
a proper v-block. These aren't going to cut it if I decide to miter in this fixture.
Bottom bracket cones or holding tooling. I'll probably knock something out on the lathe for better accuracy, but also have cones here. 
Some sort of measurement marks. 
end caps and debur everything. 
Anything that someone suggests that's rather clever to make this better. 

I built this with the following tools:

12" miter saw with a metal cutting blade
15" standing Drill press with a harbor freight 'deluxe' cross slide. (I've since returned the crappy cross slide and picked up a palmgren x-y rotary table off of Craig's list)
5/16" carbide end mill with assorted drill bits and taps
36" Belt sander
sand paper, piece of glass for polishing and a couple of files. 

The axle is parallel to the 1" thick t-block. The axle is also parallel to the bed. There is a bit of wave in the flat surface of the 8020, but I didn't feel it was on a plane that really is relevant in this setting. If I run out of things to do, I'll go find a way to mill it flat. However, I suspect I'll find a piece of 1/2" - 3/4" steel or cast iron that is ground flat before I worry about the aluminum.

This is as accurate as I adjust it. If I were to just clamp it down, it's within about .03" of being parallel to the table. Which is totally acceptable, but another minute with the dial indicator and it's good to go.

If I had a mill handy, things would have been a little different. But all in all, I'm pretty pleased with how this is working out. I hope you like.

-Brad


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## j-ro (Feb 21, 2009)

*looks good*

Hey Brad, looks nice.
heres a shot of mine, I've used a bit of round stock to center the stays on the fixture.
My holddown is just a plate like yours with a hole in it to bolt it to a t-nut in between the v-blocks. The centering device has a tab milled into the bottom of it to slide in the 80/20 groove. It also bolts to a t-nut. There is a collar that I slip over it to increase the size for mountain wheels.


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## Brad Bedell (Apr 18, 2009)

The width of the chainstay clamps was the only thing that I wasn't sure about. I chucked up a mtb bike on it yesterday to make sure it was 'close'. With the 1545 base, (vs your 1530) the 3rd groove should give me room to work on width. I like the round stock idea. I have some 2" and 2.25" round in my scraps. I was considering making my v-blocks out of it. 

Do you find the hold down plate needs anything to prevent the tubes from moving in the miter? I always assumed the dropouts, once welded in would prevent any twisting of the metal. However, I wasn't sure if you'd get enough surface area to get a solid clamp on the front of the chain stays when mitering with a simple flat plate to clamp it down.


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## dr.welby (Jan 6, 2004)

Here's some quick pics of mine:


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## j-ro (Feb 21, 2009)

Heres a couple more, you can see the bushing on my centering dowel is used to index the V-blocks as well as space the chainstays.
Also, the simple t-bar that acts as a holddown.


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## fanzy4 (Aug 19, 2004)

Here are some pictures of mine...


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## Smokebikes (Feb 2, 2008)

There are some really nice "DIY" chain stay jigs this time around.....here's mine, different in that I sand the CS down instead of cutting but it works. :thumbsup: 
Someday I'll have a lathe and cut mine, I bet it be alot quicker.........
Oh yeah, and first I braze a bridge to hold the CS's together as a unit then sand them down.


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## Brad Bedell (Apr 18, 2009)

I finally got around to building some blocks. I went to take the recycling out last night and was inspired to do some lathe work. Now I need to add a couple of counter-sunk allen head bolts for indexing these.


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## Linnaeus (May 17, 2009)

Ooo I haven't read XKCD in years. Thanks for the reminder!


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## Brad Bedell (Apr 18, 2009)

Looks like I can't edit the first thread. Just a couple of finishing touches left. Including a center line and alignment marks. Though, I'm probably 'done' with it for a bit until I start trying to use it and determine the deficiencies.


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## Brad Bedell (Apr 18, 2009)

Linnaeus said:


> Ooo I haven't read XKCD in years. Thanks for the reminder!


I figured I'd toss in the free plug there.


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## Brad Bedell (Apr 18, 2009)

One last update on this. I ended up working things over more than initially intended. I made the mistake of putting my blocks on it to check how accurate it was... Next photo will be of tubing actually set up in it.

I'll eventually build the axle block again. I'm not real happy with it, but it'll suffice for now and I don't feel like doing it again.

Does anyone know where to find the nifty adhesive measuring tape in Metric so that I can add to this?










Of course, I could have built at least two frames with the time I spent on this. But trying to remember how to machine again was worth the exercise.


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## j-ro (Feb 21, 2009)

I like how you did the V-blocks Brad. The axle block looks fine to me. I don't know if I showed it in my pictures but my axle block is fixed at the back of the fixture and I slide the rest of it back and forth for adustment.

Smoke, I like how you roll.


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## Clockwork Bikes (Jun 17, 2006)

http://www.mcmaster.com/#rule-straightedges/=bcpunz


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## Brad Bedell (Apr 18, 2009)

Clockwork Bikes said:


> http://www.mcmaster.com/#rule-straightedges/=bcpunz


Perfect, thanks!


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## unterhausen (Sep 28, 2008)

if you have a woodcraft local to you, they carry Kreig adhesive backed scales in metric.


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