New steel crank for Polar 72CE gearbox.

We fabricate these crank arms for a press fit on the shaft of the gearbox.
IMPORTANT NOTES ABOUT THE MOUNTING

Be sure to mount the pin on to the crank first. Otherwise it will be impossible to press on once installed on the main shaft. Use a mechanical or hydraulic press to do this and not a hammer.

Installation on the shaft:
Do not attempt to install this on the shaft by pounding on with a hammer!
This arm must be pressed onto the shaft with a hydraulic press and with support at the other end of the shaft when doing so.

The shaft that the crank arm is mounted to also goes through the brass worm gear which is also pressed on. It has no additional hardware holding it in place axially. Hitting with a hammer will shift this position and the key on the shaft can hit a bushing and damage the gearbox.

Taper Pin:
The hole for the taper pin that secures the arm is unique to each gearbox and should be mounted by us or a competent mechanic/machinist. If you purchase this arm with the intent of mounting it yourself, the taper pin hole will be unfinished and must be fitted to your shaft.

The pilot hole we drill will be cylindrical and not tapered. It is positioned from our sample arm and will not be identical to any other arms out there due to how these are custom fitted to each gearbox.

The trick is to remove as little material from the shaft as possible yet having every part of the taper pin touch every part of the reamed hole. Use a power drill at very slow speeds and lots of cutting oil to aid in chip removal. Never reverse a reamer.

We have combination reamer/drills for sale here G16114

IF YOU WISH FOR US TO MOUNT THE ARM
We charge $300 to mount our arm on your old shaft. We will require your old crank arm and:
A) The entire gearbox
or
B) The shaft the arm mounts to, already removed from the gearbox.

Mounting the arm for you may add one day to the standard turnaround for fabricating the arm and assuming we already received your gearbox or shaft to mount to.

Please feel free to contact us with any questions you may have at [email protected]