Sprocket, Drum and Drumscreen

Can'y you just rotate it with a clock on it?

I am not sure what you mean....

Sorry - for "clock" read "dial indicator":

If the chain is welded on the outside, it seems you want to check the chain itself. Make a sprocket that is spring tensioned to ride on the chain and put a runout meter on the test sprocket shaft. As long as you have the runout meter, clamp it over the top and measure the inside if you want.

Set up a stationary pointer off the edge of the drum and rotate the drum. Check the variation of the distance between the pointer and the drum edge where the chain is welded on.

If distance variation is less than inch use a dial indicator to get an accurate measure.

This will not tell you if the drums out of round as the axle could be located off center. measurement off the edge of the drum to the axle in several places would eliminate that possibility.

Hello staceyroberts:

You could try this: You will be using a laser measure.

Get a Laser 'tape' distance measure and hold it against something that will not move, and aim the red dot at the drum. If the drum has any ovality the measurements should alter by the same difference.

Has to be worth a try?

Good luck

Let me know if you try it and what happens please?