If you are in possession of a couple 620 spools, you may be in business. Just cut down the little fringe surrounding a 120 spool, sand off, and you're set. This works best with Kodak's spools, and since you use a 620 spool as the takeup, you have no issues with frame spacing or the diameter of the center hole. You might have a small light leak from cutting off the fringe of the 120 spool, but since most 620 cameras are more fun than professional, it really doesn't matter.