For the record, for anyone interested, here is the old English way of cutting and re- tempering mainsprings...carried out for Eons on vintage Webleys and BSAs more than 70 years ago, many of the mainsprings still functioning to this day....The master craftsman way.
You chop the spring coil through on the edge of the grinding wheel....heat the end to orange heat and drop it onto a guide rod or mocked up guide held in the vice, quickly pushing down with a leather gauntlet or flat piece of metal.
The spring exactly follows the square face of the base of the guide and kept perfectly square by the tube part of the guide it is sat over. Perfect square mainspring end.
We can then offer to the side of the grinding wheel to flatten further.
Here's the shocker..
Quenching was actually done into water. ..the way I do it.
This potentially makes the mainspring end quite brittle, but then heating again until a dull blue is achieved (just past purple) and quenching again.
That's the true way old mainsprings were made correctly ...
Another simple way is quenching straight in Parrafin, which offers some level of tempering unlike oil which can be too slow a quench for correctness.
Forget this new contrivence of letting it cool in air...Yes it will avoid brittle issues for the unskilled but the last few coils run the chance of losing potentials.
Polishing ends....well there's no harm doing it is there and brings a sense of job satisfaction.
You chop the spring coil through on the edge of the grinding wheel....heat the end to orange heat and drop it onto a guide rod or mocked up guide held in the vice, quickly pushing down with a leather gauntlet or flat piece of metal.
The spring exactly follows the square face of the base of the guide and kept perfectly square by the tube part of the guide it is sat over. Perfect square mainspring end.
We can then offer to the side of the grinding wheel to flatten further.
Here's the shocker..
Quenching was actually done into water. ..the way I do it.
This potentially makes the mainspring end quite brittle, but then heating again until a dull blue is achieved (just past purple) and quenching again.
That's the true way old mainsprings were made correctly ...
Another simple way is quenching straight in Parrafin, which offers some level of tempering unlike oil which can be too slow a quench for correctness.
Forget this new contrivence of letting it cool in air...Yes it will avoid brittle issues for the unskilled but the last few coils run the chance of losing potentials.
Polishing ends....well there's no harm doing it is there and brings a sense of job satisfaction.
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