"Lynn" wrote in message
...
snip
Most of the repairs were done by carefully honing out the grooves in
worn
pick-up and record heads. Probably not accepted practice, but, hey
it certainly put a lot of tape players back in business at the Danang
Airfield tape library back in service!

Old Chief Lynn

Yes, what you call "honing" is a costly (and time-honoured) service call
"lapping". Many heads are unavailable, and this is a good way to kjeep
machines in service for much longer.