Matchlock spring hardening and tempering.

[smallpatch]

I’m working on a matchlock lock from the rifle shop.
It’s very basic with only one spring for the sear. 
According to TRS, it is 6150 steel. 
I need a little help on hardening and tempering.  Any help appreciated.

[Bsharp]

1550-1650 Heat
https://www.blksmth.com/heat-colors/
or use Tempilaq
https://www.brownells.com/gunsmith-tools-supplies/metal-prep-coloring/heat-treating-accessories/tempilaq--prod13124.aspx
or Infrared Thermometer
Cool in 150 degree oil
polish if needed
Wrap in tin foil and cook with Pizza at 400-450
leave in turned off oven to finish cooling

[deepcreekdale]

I follow Rifle Shoppes instructions for hardening their springs. Heat to Cherry red with an acetylene torch and quench in water. They say to use the temper in burning oil method, but I use a lead pot with a thermometer keeping it at 720 degrees for about 20-30 minutes. I have had perfect results every time.

[smallpatch]

Thanks Dale!

[Bsharp]

Fun facts:

When tempering unknown steel, always use oil first. Then water.....if you have never seen your work shatter and crack, then just use water.

There are exceptions, I was doing spring steel. 1075 or maybe 1095.....oil didn't work, didn't want to use water, so I tried Mineral Oil. Worked great.

[P.W.Berkuta]

1075 is a oil hardening spring steel and 1095 is a water hardening spring steel but you are correct to play it safe on using oil first if unsure.