Joined: Jan 2009
Posts: 44,139
Likes: 6,366
From: New York, NY, and High Falls, NY, USA
Bikes: 1962 Rudge Sports, 1971 Raleigh Super Course, 1971 Raleigh Pro Track, 1974 Raleigh International, 1975 Viscount Fixie, 1982 McLean, 1996 Lemond (Ti), 2002 Burley Zydeco tandem
You should be able to get away with screwing them into an English-threaded crank. I did that for a while, and I didn't ruin anything. Make sure they're tight but not too tight. Sorry I can't quantify what those terms mean.
Or maybe use some shim material? Plumbers tape?