Surface Hardening....Anyone here done it?

[John Rogers]

I am talking about two products namely Kasenite or Cherry Red. Both are a powder that are used to cover small areas of non stainless steel once the piece is heated cherry red in temperature, cover the metal, re-heat to cherry red then quench (oil or water). My gunsmith mentor uses Kasenite mostly but it is not normally sold in small quantities to harden the tumbler in a percussion rifle lock after you do some stoning to make the trigger break clean. Also used in percussion trigger parts after stoning to lower trigger pull.

I recently did the trigger work as he told me how and dropped a single set trigger from 4# pull once it was set down to 1.5 OZ which is much nicer for target shooting. I plan to wait a few days until our heat wave dies away some since working with 1600 degree steel when it is 90+ degrees is not pleasant.

So has anyone here done it? I watched him use it several years ago and the YouTube videos and have the heavy leather gloves and a leather shop apron so......?

[908/930]

Sounds like you want to do some carburizing, I have done lots of heat treating on small parts but mostly tool steels.

I would use oil not water it cools at a slightly slower rate, I think less likely to get stress cracks, make sure you have enough proper oil in a steel container to completely submerge the part, or it will likely catch the oil on fire. Practice on some similar size chunks of steel.

[LWJ]

I annealed and then tempered s pice of steel for s knife my son made. Not hard.

This seems similar.

Preparation and planning are key. Stuff is hot. Time is critical. Set up the work space for success.

[Mericet]

I have used Kasenit in the past and it does work well. As long as you have the means to get to the required temp it should not be an issue. Brownells sells a similar compound for about half the price. https://www.brownells.com/gunsmith-tools-supplies/metal-prep-coloring/color-case-hardening/surface-hardening-compound-sku083000033-27119-52952.aspx?cm_mmc=cse-_-Itwine-_-shopzilla-_-083-000-033&utm_medium=cse&utm_source=connexity&utm_campaign=itwine&utm_content=083-000-033

[masraum]

wait, you went from a 48oz pull down to 1.5oz? Or did you go from 4# to 1.5#?

[John Rogers]

The trigger pull after being set is 1.5OZ measured with my brand new Lyman electronic trigger pull gauge. I was really surprised and the parts that are touching had to be really stoned to get smooth. According to L&R the trigger maker single set triggers are not polished at all? So I polished the parts and want to make their finish a tad more durable.

[petrolhead611]

When I was an apprentice over 50 years ago the heat treatment room was to me a terrifying place of hot cyanide baths and tricothylene cleaning tanks. I spent the absolute minimum time in there.

[908/930]

Unless you really want to do this yourself, you could also contact a heat treating operation, there is a good possibility of your part tolerances changing. If sent out another option would be nitriding, less likely to change size. Most of the time heat tread is completed before final grinding.

[John Rogers]

From what I saw of the three moving parts that make up the single set trigger the only part that was machined and polished is the tip of cocking arm. All other surfaces are as they were cast as I was told by a fellow at L&R locks/triggers. Since I polished the surfaces that rub together even slightly I figured hardening the surfaces would allow them to move smoother. As small as they are, I figure it would be a waste of time and money to try and get a shop that does this sort of thing?

[unclebilly]

I have had 10’s of thousands of parts liquid nitrided (ferro nitro carburizing), gas nitrided, and carburized.

We are just now doing testing of Gas FNC Which is similar to gas nitriding but different.

If I was you, I would look for a place in town that does liquid nitriding and see if they can toss your parts in with a batch. Make sure they keep the temps below 1100F and you should be fine. Have them apply the black oxide coating and your parts will look amazing.

You can’t get good results in all metals with the other processes and anything with thin features will become brittle with gas nitriding.

[John Rogers]

Well yesterday evening after it cooled off a bit I did the hardening treatment. I already had a torch but it was one that screws on the gas bottle so I bought the one Harbor Freight sells that has a hose so I just had to hold the torch head. I used a piece of piano wire through the hole in each piece and since we had a fine breeze I put some Cherry Red in a tin cup and also put some used motor oil in a container to do the quenching. On came the torch and it took a while to get the little piece (one at a time) so it was red hot as required then into the powder to coat the part. On came the torch again and it got red hot again for a few minutes then into the oil to quench. That took a couple minutes then brushing with a steel wire brush to get rid of all the blistered Cherry Red.

I repeated this for the other two parts and then took a piece of extra fine crocus cloth to wipe each surface. I was surprised how slippery things were so I put the trigger back together. Set it, released, set it and repeat several times and adjusted the trip screw. Pulled out the trigger gauge.......1.1OZ clean break after half a dozen cycles. I was surprised what a difference all this made. One of my shooting buddies is super happy his 1911 is 4# when the hammer is cocked first and now he wants me to work on it but I said nooooooo.

[Bill Douglas]

I remember engineering class at school. We used to heat the metal until glowing red in the furnace then dip it into a bowl of carbon.

These days to get it really hard they dip it into a bowl of viagra.