2:1 Internal & Spur Gear

[Clarence L.Snyder]

Dan Llewellyn2 wrote:
> 
> This is not exactly EFI related - but my local sources have
> been unable to help me.
> 
> I am trying to build an experimental transmission.  It uses
> an internal gear (teeth on the inside) and a spur gear (teeth
> on the outside) that rotates inside the first gear.  My only
> requirement is that the internal gear needs to have exactly
> twice the teeth of the spur gear (and mesh, of course).
> 
> I went some automatic transmission shops, but all the sets
> of internal and planetary gears won't work because the planets
> are too small.  I was hoping internal and planets from different
> sets might work,  but haven't found a match.  I figured that
> buying some used automatic transmission gears would be
> the cheapest way to get some quality gears.
> 
> Any ideas?
> 
> TIA
> 
> Dan L
You will have to have at least one of the gears custom made. I have
TRIED to find automotive gearing for this exact setup - but looking for
just OFF the 2.0:1 ratio. There are a few sun gears (GM 700) that match
a few ring gears (ford c3 if I remember correctly) with the right lead
on the helix, but the ratio is too steep.