273 adjustable rocker conundrum..

For geometry reasons I'm being forced to use my 273 rockers instead of the crane rollers I have... Crane no bought out by comp no longer sells the adjusters with the locking nuts... Everybody's out I've looked for them .
I don't know if I can just bugger up the threads on some adjusters so they get more stiff or what..??
If anybody's tried something that worked I'd sure like to know...