Originally Posted by
Aubergine
It turned out that the bolt hole in the spindle was loose, so the bolt just would not hold.
Aren't the bolt holes drilled and tapped directly into the spindle? I guess I never looked close enough.
Originally Posted by
base2
Not really worse than you thought. Bottom brackets are <$25 for just about any generic. Are there plenty for way more dollars? Sure. Yours? Probably cheap.
A cheap torque wrench is less than $30
The bottom bracket socket, (assuming cartridge type bb) is under $20
Boat trailer axle grease is cheaper than dirt. Grease all your threads.
Under $75 dollars in total to do it yourself.
As far as the crank arms go. That could be pricey, but it doesn't have to be. Square taper cranks are out of fashion. Hollow Tech II, GXP, BB30, etc... is all the rage now.
If it's indeed a case of initial loose fit as suspected, the BB itself is probably fine. Hard steel BB, softer aluminum crank arm, the BB wins and the arm loses. As for crank arm cost, switching to another technology would be expensive, but square taper cranks are easily had at any bike co-op. Depending on concern about weight balance and aesthetics, the OP could even opt just to swap that NDS arm, since the DS is single speed. Sourcing a single orphaned arm with no need to match it gets you into the "donation to the co-op" price range.
And +1 on the marine grease; it's water-resistant, and several LBSes around here swear by it. Available at any man-mall.