It would appear that I have posted a series of identical messages to
this group. I was trying to help a guy with a question he posted in
sci.engr.mech. My ISP's news server has been misbehaving recently, and
my posts to sci.engr.mech went missing. So I posted them again,
unfortunately not realising that replies were also being posted to
rec.crafts.metalworking, and that these replies were not getting lost.
Pleaase accept my apologies.

Chris Tidy