# Homemade Seat Stay Bender



## Smudgemo (Nov 30, 2005)

I thought I'd share my version of a stay bender made for the cost of O/A gasses and $2 worth of hardware. I learned the hard way that these TT 19mmn seat stays don't bend like forks, so I did some MTBR research and came up with this. The angle iron is cut from a 5' piece that's been laying in the back yard since before I bought my house. The pivots are cut off chain stay tips with halved tubing from the scrap bin brazed on. The radius kind of sucks, but it's all I had on hand at the moment and I'll admit I didn't spend much time on it.

I'll probably pick up some maple and groove it properly later. I also need to reinforce the bolts a little more nicely because 3/8" obviously can't handle that kind of force. The 2x4 pieces fit perfectly by chance, so it was fine for now. 

I also froze water in the stays based on a prior thread discussing bending, and it seems to have helped a lot. I think a nicer radius piece might eliminate the need for freezing, but I didn't want to wreck two sets in one weekend so I tried all the tricks. This was the first time I didn't use straight gauge or S-bend stays, so lesson learned. For reference, the tubes were simply capped with electrical tape and left all day in the freezer.

The bends turned out pretty good. I can feel a tiny bit of a ripple, but I can't see it. Maybe it'll be visible with paint. I'm happy to entertain suggestions for improvement. 

Best,
Ryan


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## smudge (Jan 12, 2004)

nice work. It's pretty satisfying to make a tool that gets the job done...cheaply.

Smudge Cycles eh? I had a company in the 90's by that name when I was designing bits for trials bikes.


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## j-ro (Feb 21, 2009)

Will the real slim shady please stand up, please stand up........


I second that, the bends look great.

You can always make one of anything, making a second one to match is the hard part. those look good.


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## Golem builder (Jul 31, 2009)

Nice!
Good to know that the water trick works. Did you mixed up soap with it?


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## Smudgemo (Nov 30, 2005)

Ha ha, imagine my surprise finding out a name like SmudgeCycles isn't exactly a new idea. 

No soap was harmed in the making of these bends, but I suppose it's worth a try depending on what is supposed to happen.


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## GrayJay (May 16, 2011)

How does filling the tube with ice compare with packing them full of sand?


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## jasong (May 20, 2004)

There are a few tricks for tube bending, but sealing of the ends is important if you want to minimize movement internally (or that the substance leaves the ends). Some will melt a low temp metal inside too, like cerrosafe, bend, then lightly warm to remove.

@ Sm : how symmetric were the two after the finish (vert+horiz) with your jig? Photo looks good. Nice idea.


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## Smudgemo (Nov 30, 2005)

jasong said:


> @ Sm : how symmetric were the two after the finish (vert+horiz) with your jig? Photo looks good. Nice idea.


They were pretty good, but not perfect. The placement of the bend was off just a bit, so I compensated by adjusting the end cuts slightly so the bend was in the same place on the frame. 
The error was small enough that you couldn't really tell any difference unless you looked closely, but next time I'll take more care to mark and place them better. I was sort of winging it, but they turned out fine and the bike looks great.


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