I was just browsing my usual and ran across a user on Ebay called helicoptersean who makes custom ABS friction or press fit one piece seamless follow focus gear rings for just about any lens you want, and for around $35.

This is WAY less expensive then the Dulco mod.

He apparently can make them to your width and diameter specs too if you want to slow down the rotation with a larger gear.

They can be had two ways, either where you heat them up via your in-house "Chef Mic" or in boiling water, either way for a real snug fit, or a cold hand press friction fit where they stay put but can be easily removed too.

He writes that you measure your particular lens' O.D. with a digital calipers, forward that spec., and he'll send out sample fit gearless ring set and then tell him which one fits best, then he makes the gears iwithin a few days of receipt.

Offers a money back guarantee. As soon as I get two more lenses in, I am going to order sets for all three.

Thought this might be of interest to fellow members.

helicoptersean on eBay (http://www.ebay.com/usr/helicoptersean)