Sjtaylor

I used my forging skills to fabricate a chainstay dimpling die. Tried it out first on a scrapped frame and then dimpled the chainstays of my 700c conversion all-road bike build. The frame is a 1982 Trek 710 with clearance for a 40mm tire everywhere except at the chainstays. I fixed that.

If I were to use this die again I would convert it to a four post die instead of just two and probably lengthen the dimpling punch in stead of walking it along to elongate the dent. It got the job done though..

Thought this might entertain some bike wrenchers here.

Thanks.

Trakhak

You might want to ask the moderators to move this thread to the Framebuilders section. There are people there with stories to tell about dimpling chainstays.

blamester

Tidy work. You are gonna end up with a good bike.

Sjtaylor

I didn't think of that. I also have no clue how frame builders dimple tubes. I'll have to read some of those threads.

Opening up for tire clearance is sure going to make this build a lot more fun.

Sjtaylor

Thanks. I just gave that frame a Sugino triple and I've got an 11-36 9 speed cassette and a Deore XT rd for it too. I'll have a true granny gear.

JohnDThompson 

One of my first jobs at Trek involved indenting chainstays for tire and chainring clearance. This was done before the tubes were brazed, but after the dropout end was milled and slotted. There were Arbor presses with forms similar to those @Sjtaylor used. The dropout slot was used to index the indentation in the proper orientation. I'd crank through a box of chainstays, miter the bottom bracket end (again, a dedicated fixture); mill, slot, and trim a box of seat stays, braze TREK caps on the ends of the seat stays, finish the cap so it was flush with the tube, grab a box of dropouts and braze them all together in another dedicated fixture that set the proper seat stay/chainstay angle for each frame size, and hang them on a rack to have the flux removed before being attached to the main frame triangles.

tFUnK

... can this be done to a 3/2.5 Ti chainstay?

_ForceD_

Can it be used on the exterior of the chainstay? A couple of my bikes have dimples on the interior AND exterior of the drive side stay...to accommodate the inner chainring.

Also...it doesn’t appear that you blemished the paint finish (unless painted after you made the dimples). Good job.

Dan

Sjtaylor

I coated both faces of the die with heavy grease and the process left no visual marring of the paint. I can't say the paint isn't compromised at the indent but I don't see anything.

This was a fun experiment. I don't have enough parts in my stash to build this frame so I may look for a donor bike or take one from my fleet. I did 20 miles on an unpaved rail trail today on the bike in the photo. It got me thinking how I can perfect an all-road bike build.

_ForceD_

Well anyway...I love constructing of, and the uses of ones own tools. Well done.

Dan