Marciaga

Update. Tried two different mediums for quench peanut oil at approx 250f Boiling water approx 210f result for oil, hard as XXXXX no grab from a coarse of fine file. (WONT BREAK) in quench form result for water is the same (WONT BREAK) grinded down to chisel point, hard as XXXXX won't chip or break, clamped XXXXX in vise struck with 3# double jack, will not break or bend... Even more confused. i ran it opposite as well with the forge performing the preheat and the digital controlled fire box at 1950. Completely confused. Truth now is I'm just going to run some work with it in quench state. See how it goes... cheers. Please actually read the Terms of Service you agreed to follow in order to be a member here. this is a G rated forum. You have been warned before.

Rodger that, will have a test run tonight. Won't machine this one down just destructive testing time.

The manufacture recommended 1000-1100 for two hours (double tempered) however they did not specify the HRC I would get. it did also indicate to NOT temper below 1000... I had two pryo meters and both checked within +- 5 degree of each other. Missle test tonight! Very good point, I will look into this option. Thanks Thomas.

Now that is a XXXXXXX good Idea! Haven't even thought of that, although I did skate a file over the piece. It didn't grab but I think it would be a great idea to attempt to shatter a piece for fun. Thank you Charles. Please review the terms of service you agreed to follow when joining.

Oil approx 150 F, have the large pot of oil on an electric burner at the ready when the part comes out of the furnace.

Using Canola, Also tried Peanut. Yes sir on moving it around, but I have been getting flare up flaming with the canola. I'm thinking of trying a heavy water / brine solution next. Just for testing purposes... I am just stubborn, ill exhaust all my ideas and efforts before waving the white flag. $170.00 for a run of 30 chisels to 62 HrC pick up and delivery free. Not a bad deal at all.

I didn't double temper,but you'd have to figure it would still be brittle right? Maybe my oil is forming a vapor barrier around it and not shocking it to solidify the grain structure... It is rather temperamental...

Greetings, in the past I have had great luck with all tool and steels with respect to heat treating. However, PMM4 has perplexed my abilities, and it could be the capability of my home shop environment. I am preheating in kiln to 1500f equalizing rapidly heating to 1900f (recommend by supplier for cold working tools) soaking at this temperature for 20 minutes (in propane forge) quenching in oil to approx 8-900 f (blacked) air cooling to 125f tempering at 1000f for two hours. I don't have a HRC tester but it's clearly not upwards of 60-65. I have contacted some services who have great prices for a run of my chisels but I would love to do this myself as I have always done before. Thank you in advance for any info or tips within the steps.