"John Doe" wrote in message
...
Using 6061 3/8" thick aluminum to hold the front sprocket on a bicycle.

A 1/2 inch square hole through 3/8 inch thick aluminum fits over the
bottom bracket square tapered spindle. The spindle has rounded corners,
so it's not the ideal grip. But the flatbar will be pressed onto it
using a hard bolt.

Will 3/8 inch thick aluminum flatbar fit snugly onto a bicycle bottom
bracket square tapered spindle survive the torque?

Thanks.

I'm probably going to find out. Currently, it's the least difficult way I
know of to attach a custom sprocket to a bicycle bottom bracket.

So this is what you wanted your square hole for?

Both the taper and the length of contact between the spindle and the crank
are extremely important.
The taper is swaged into the crank to insure an accurate match. When bolted
down they form an interference fit that keeps them aligned and keeps them
from wallowing each other out.

I would suggest working out a way to adapt the business end of a
cannibalized crank to hold the sprocket.

Paul K. Dickman