I've looked at this, too. There is a thread on Armorama, about "Tiger 1 Turret" something over on armorama, you can't miss it, it is a VERY long post, 7+ pages I think, last time I checked. Here's the link:
http://www.armorama.com/modules.php?op=modload&name=SquawkBox&file=index&req=viewtopic&topic_id=131182&page=1
THe guy used, IIRC, Tamita putty, but he used all kinds of differnt things, including a gear from a venitian blind, as well as dedicated tools, and he posted what they all looked like.
I recently bought a Lion's Roar tool that is a cast handle, with a tapped receptacle for a screw, that holds a series of differentyl sized and patterned rolling geared wheels.
I have not tried it yet.