Ore 520. I've played with the spacer trick. I sharpen .080 processor chains about once a week for a local firewood Co so do adjustments on a regular basis. Giving the handle a wack with my hand to tighten it up helps but, again, the problem isn't with securing the drive link (only one gets clamped), it is with the slop inherent with all chain...the cutter moves. Not a lot but enough to irritate me