Work hardening steel

[B.Habermehl]

Just ran into a problem with drilling a Davis lock. It was no doubt, more than likely my fault, running the drillpress too fast no oil etc. I managed to work harden the surface around the holes. Tapping the holes was a sonofagun, A newbe with a tap would have definately broken a tap. Got her done with a rediculous amount of carefulll fussing. I threw away the tap after the job was done. Just a word of caution use coolant,oil, etc when drilling pilot tap holes in locks. If the drill resists cutting replace the bit or sharpen the drill bit.

[bob in the woods]

You could always anneal  it. 

[Lucky R A]

  Bob, what is your method for annealing the air hardening steel used by Davis in their triggers.  I understand that it takes an extended heat soak to to make them soft again.  I have broken triggers after heating them to reshape them.  They become brittle as glass, and heating and letting them cool slowly does not anneal them. 

[okieboy]

 If you heat A2 and let it cool in still air you are hardening it, the air does not need to be moving. To anneal A2, it needs to be heated to approximately 1675F and then cooled at a rate of 20 degrees per hour, so getting down to 875F would entail 40 hours cooling. That is really slow cooling. Easy enough for the home mechanic to harden this material, but annealing doesn't sound too appealing.

[bob in the woods]

Re annealing. I only did one plate which I had the same trouble due to a dull drill bit. I put it in the woodstove, [ winter..around noon ] and took it out with the ashes in a bucket in the morning. Jusst left it and built a new fire. I don't remember how long, but when the ashes were finally cool, I sifted it out and it seemed to drill OK.  Maybe I got lucky.

[Dphariss]

Heat to cherry and place in dry wood ashes.
It should full anneal.
Woodstoves in winter can make the part hotter than is desirable but it will work and I have done it though toward the end of the burn just put the part in the bottom of the coals and let it burn out and cool.
Easier/faster just to heat and place in the ash.
Dan

[bgf]

I gather the Davis lockplates are not the same steel as the triggers -- I sure hope not!  My understanding on the triggers is that in lieu of annealing to work, you are to bend them hot and then temper for 1 hr. at 550 degrees.  I did this, but I will not be using those triggers until another build, so I don't know if they really are tough or will break like glass.  As they came, they "felt" quite brittle, but I'm sure they were fine -- lots of satisfied customers; it is modification that the sticker with them--hard as a rock, which is good for wear surfaces.