On 4/23/2011 7:16 AM, J. D. Slocomb wrote:
...
I am building an engine; this is a step-down drive for an output shaft.

RPMs would be 2500 tops, pull on the chain might be maybe 100 lbs at the
most.

The final drive will use bicycle chain, so I want to use something much
stronger than that inside the engine's case.

Does it need to be chain? Vee belts have also been used for similar
types of drives.
Cheers,

John D. Slocomb
(jdslocombatgmail)

It needs to be a chain, since the drive is taken off the mid-point of
the engine's shaft--which is inside an oil-filled case.