I made a set out of drill blanks...5/64" (.078 / 2mm ) happened to be long enough for my application. (early O.S. FS .40 damaged in a crash ) Got them from McMaster Carr. (actually they were robbed from my slot car armature shaft stash ...same item )

I borrowed a friends engine so I could measure them to get the right length. Trimmed with Dremel cut-off wheel...then carefully put a radius on the end by twirling the ends on the face of the wheel, then polished w/ 600 wet/dry and oil.

You could probably also use music wire.

What engine do ya have?