Maybe if you find some way to cover over the threads...
Anyhow, I measured my trem arms diameters. My Ibanez arms are 6mm while the Parker arm is just under 5mm thick. I'd love to find a replacement arm that's shorter and bent the way I prefer. Or at least another 5mm arm that I can mess around with and not screw up my stock arm.
Well I took about 15 minutes the other day and filed down the threads on the arm. Just a plain flat file and a little attention to avoid flat-spotting. All that's left are little lines showing the valleys of the threads. Very smooth to the touch. Seems to work fine.
I'm very interested to your operations with the tremolo arm on your dragonfly. Two question. The arm you've bought need some modification before being inserted? Starch could damage the bridge? Sorry for my english, i'm writing from Italy.