Alternative crank mounting methods

Joined
Mar 7, 2017
Messages
9
Location
vancouver
Hi Builders,
Wondering if anyone has come up with a good way to bolt the crank to the frame, like for example through the chainstay stubs. The challenge, as I see it, is accurately drilling the holes so that the chainring is properly aligned with the chain.
I wish I still had access to welding, but I dont, (and I suck at welding too tbh).
Regards,
Rob
 
Joined
Feb 7, 2008
Messages
2,715
Location
Nottinghamshire England
What frame ?

Building what ?

regards Paul
 
Joined
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Joined
Mar 7, 2017
Messages
9
Location
vancouver
Thanks for the links.As for the rest of the marauder I did the weld myself back when I had access to a makerspace. Since then, one weld had to be broken and repositioned and I used about a dozen sheet metal screw and 1/8" plate to lap join it. I recognize that the atomiczombie design is well thought out and well tested, but the crank mount is designed for adjustability and I thought with that constraint relaxed, maybe something even better can be done with bolt holes through the bottom bracket shell straight into the frame. But then the screws would not be in perfect shear load so I can only guess how rigid that could possibly be....
 

Twinkle

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Iirc an English forum user, used 2 exhaust clamps two 4 hole square plates ( top and bottom of frame ) 4 stud joiners and 4 short bolts .This seemed to work for his swb lowrider .
 
Joined
Feb 7, 2008
Messages
2,715
Location
Nottinghamshire England
Ok a BB has 3 tubes going into it ?

chain stays - seat tube and down tube.

What you need to do is find a BB where either the seat tube or down tube neatly fits inside a piece of square tubing [ preferably the same size as the frame main tube ] bolt through to hold BB to square tube and then bolt square tube and main frame together ?

Clumsy , heavy and bulky but should work.

regards Paul
 
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