31mm OD seems to be a common bearing size for bottom brackets. If one could find some reasonably deep 31mm ID caps .....Miles wrote:You could sleeve the BB shell and press in a pair of 24x31x20 drawn cups?
Miles wrote:. . . You can try it out on one of your old bikes.....
turbo1889 wrote:Continuing evolution of the design based on further improvements that Miles has put forth in his thread on the same subject:
----- 1.37"-24tpi x 73mm bottom bracket reamed on each side to accept press in bearings of 35mm outside diameter.
----- Primary bearings are 28mm x 35mm x 20mm (ID x OD x W) directly pressed into bottom bracket from each side.
----- Outer spindle shaft is 28mm outside diameter and screws together in the center via. M24-2.0 LH thread 30mm long.
----- Secondary bearings are 17mm x 21mm x 13mm (ID x OD x W) pressed into the two ends of the outer spindle shaft.
----- Inner spindle shaft is 17mm outside diameter solid with tapered square end.
----- Axial containment and sealing of the primary bearings is provided by simple brass washers taking up the slack between each side of the bottom bracket shell and the outer spindle.
----- Both sides of the outer spindle use standard 1.37"x24tpi RH threaded freewheel threads to accept White Industries Heavy Duty crank freewheel unit.
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