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Anyone has a Dremel I could borrow for a weekend in January? :D
Got one, in SE24 if that's convenient?
mashton-
That would be awesome! But gotta postpone it as I've had to come to Hungary for a while while Covid runs its course. Left most of my stuff in London though, so time to dig up some older projects!
Im currently riding this when in Hungary, 2008 (?) Orbea Onix with a mixed ultegra group. Hoops are from on here, Reynolds tubs on white industries hubs.
Onto the current project! This BMC bike has been about 8 years in the making. Bough it with a cracked top tube, and missing seatpost. The seatpost was quite pricey -which is understandable, its sub 200g for an aero seatpost-, so because of the sunk cost I just HAD TO build it up at some point. Ive finally had the frame repaired last year, and now its time to put it together.
Waiting for a derailleur hanger, and I'll put on an 11sp Campagnolo Chorus groupset on it that Ive bought on there for a mate. He was kind enough to lend it to me while Im in Hungary. 3T finishing kit, not the poser one on the pics :)
And why is this not my main bike? Its a tad bit big for me. Had no idea about bike fit stuff when I bought it...
Theres a pics showing the repaired top tube as well.
kiskubai
Repurposed this thread to keep track of all my bike related tinkering and projects :)
Next up, fixing my broken Dolan Track Champion! Or more like crack champion...
This is the current state of affairs:
Whatever the solution is, it has to cost me less than £100, as for that price I could easily buy another frame. But the idea is that I'd rather not trash an otherwise perfectly fine frame. Im not counting the hours ive already invested into this, just material / tool costs.
Possible solutions that I've explored:
Machine an insert with 27.2mm outer diameter, 25mm inner diameter, and a collar to take on a standard seatpost clamp. Then glue this insert into the frame. Probably the least complicated solution, but need my mate to do the machining part (hey @hma !), ship it to me...etc. Also not the cleanest look. I'd need further tools to level the top of the seattube.
Make a quill seatpost. Upon closer inspection only the first ~10cm of the frame is bored to 27.2mm, after that it extends into the aero shape, so adjustability would be minimal.
Glue a 27.2 carbon or AL tube into the frame, and use a seatmast topper. Limited adjustability, and apparently seatmast toppers are neither cheap, nor easy to find.
And probably the most complicated version: Create a jig for a dremel that rotates around the seat tube and machines it down to a uniform 31.8mm that will accept a standard seatpost clamp. Ive seen this done on the same frame by Dolan as a warranty job (and on later models of the Track Champion they adopted a seatpost clamp that follows the shape of the seattube).
Here's where I am with the jig design:
First there's a quill mechanism that fixes itself into the seattube, and has a collar on top to provide a level surface to rotate on. The jig itself is 3D printed and assembled with some standard M5 nuts and bolts. It has a stopper to avoid accidentally machining it smaller than the desired diameter, and it will have a spring (tensioned by a screw from behind) pushing on the sliding dremel mount to force it in the direction it needs to machine off.
Ignore the rectangular protruding thingies, thats a leftover from a previous version that was only 2mm thick (to bring the dremels head as close as possible to the working surface), so it was a place for some steel rods to hold it all together. The dremel head is plenty close, so made the body 10mm thick at the end.
I'll probably finalize this design and do some prints over the next few days, lets see how it goes! If anyone has any suggestions design-wise, Im all ears! Im not an engineer, just played a lot with Legos as a kid :P
PS: .....Anyone has a Dremel I could borrow for a weekend in January? :D