heat treating PGW short stroke links and lifter arm

[cal44walker]

After fitting and using the PGW short stroke kit in my 1873 Uberti lever action I have noticed a lot of wear especially on the lifter arm where the spring acts on it. So.....heat treating time. I tried to contact PGW to find out what steel type they used but got no response. I'm guessing 4140 or something very close. Question is whether there is enough carbon in it to harden by heating it cherry red and quench in water or if it needs to be packed in charcoal and set in a furnace for an hour or 2 and then quenched? Anyone have any ideas? I could get hold of some Kasinite like stuff but I would rather do the job properly. I have access to a furnace.

Matt

[Coffinmaker]

I don't know about rhe heat treat, but what lever side springs are you using???  PGW SS kits require the side spring for the lifter arm be greatly reduced.  The kit includes positive slam down so the only purpose the spring serves is to hold the carrier bloc up long enough for the breach block to strip the cartridge.  Any more tension on the spring than that is wasted.  The kit carrier block arm is fairly soft.

Coffinmaker

[wildman1]

I have found them to be very helpful with any questions I had. I would be interested in your results on heat treatment. WM

[cal44walker]

The steel is 1080. Heat it to 880 Celsius in a furnace for around 15 minutes and quench in water immedeatly. Then temper in a oven at around 250 degrees and allow to cool in air. I'll be doing this in a week or so when I get access to the furnace.

cal44walker

[cal44walker]

Finally got around to heat treating the short stroke kit. Good and bad news. The good news is that after 10 minutes at 880 Celsius and a cold water quench the lifter arm hardened quite well without major distortion. The bad news is that the links distorted much more than I had predicted and the dimensions of the holes and other areas changed too much. I had to use a furnace with a normal air environment and this also caused some scaling on the parts. With the links the already sloppy fit got worse meaning headspace was too big. so a partial success. So if you are going to heat treat your links would advise the following:

1) Only treat the lifter arm. 880C for 10 minutes, then quench in water.
2) Cover the hole on the lifter arm with a little clay or press fit a dowel in there to prevent scaling. The hole went from 5.1mm diameter to 5.3 mm after scale removal giving the already generous fit even more slop. Covering it will prevent this.
3) Do not heat treat the links. Use lots of grease to reduce wear instead.

cal44walker

[Lumpy Grits]

Most quality made springs either flat or coil are from 1080 alloy.
Along with most gears.
LG