"John B." wrote in message
news
On Wed, 13 Apr 2016 21:26:18 -0400, "Jim Wilkins"
wrote:

"John B." wrote in message
. ..
On Wed, 13 Apr 2016 12:32:14 -0000 (UTC), John Doe
wrote:

John B. wrote:

John Doe wrote:
whit3rd wrote:
John Doe wrote:

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.

Why can't you use a proper crank with spider that takes
replaceable
ring gears?

Because I'm using a 450 max RPM motor to turn the
sprocket/chainring.
The chainring must be extraordinarily small, like 14 to 18
teeth.
There are no crankssets with chainrings that small. That, plus
I
wouldn't want/need the extra hardware.

Inner chain rings on a triple often are in the 20-something
tooth
range. I'm looking at a 24 tooth at the moment and there is
easily
enough meat there to go to 20 teeth and maybe even smaller.

Even if it could be down to 20 teeth, it wouldn't work for my
application.

If there were an easier way to do it, I would have found it. I
already
have turned the other three parts of making an electric bike into
ridiculously easy tasks (with hardly any tools). Easily cutting a
square
hole through an appropriate piece of metal would make it all four.

One can only speculate, "is your way the best way"?
--
Cheers,
John B.

"If all you have is a hammer, every problem looks like a nail".

True, but all problems aren't nails. I think that you'll have
problems
installing window glass with your hammer.
--

Cheers,

John B.

A hammer is exactly the right tool to help chisel out the old putty
and tap in the glazier's points.

It was even the right tool to adjust the output of an old Harley's
three brush generator.

--jsw