[Sherman]

I think I'll try doing a semi without waiting for these semi options being offered on some of these boards, I've looked at the build photos on Weaponeer and the MG 42 board and it doesn't seem too tough. However, when I started working on the bolt I discovered that sucker is HARD, I mean extreeemly hard. Any thoughts about how hot and for how long I need to keep it hot to aneal it so it can be worked with HSS and carbide. I can mill it with carbide for the denial block by taking light cuts and lots of coolant but I don't have carbide drills that would work.

Since this thing is a pistol cal ctg, a hot one at that, any thoughts about re heat treating after all the work is done ?? Are all of the different makes of these that hard ?? I think my kit came from OOW 4-5 years ago.

Thanks in advance for any ideas, thoughts,or help, Lon

 

[30calmachinegunner]

unless you know what type steel it is it would be a crap shoot trying to anneal or expecially try to reharden it.

 

[Ouchman]

Ditto, traded mine before any thought of modifying it. Very hungry; insatiable SMG. So far this is the only weapon I've ever let leave the fold. See my other posts on this subject.

 

[Sherman]

Wow, these guy's are drilling the bolts for the floating firing pin, I guess I'll just do a web search about anealing and take a shot at it. I have the semi fire control set up and I made the receiver with a denial block built in, I've done the barrel ext, 16 1/4 in, all thats left is the bolt. Bolts are cheep, if I mess this one up I'll just get another bolt. Thanks for looking, Lon

 

[BIGGUNDOCTOR]

The bolts are case hardened from what I understand. Once you get through the skin they are easier to machine. You can do spot anneling instead of doing the whole part. Anneling would be the easy part. Use some heat treating foil to wrap it in, and toss it in a fire hot enough to get it a dull red. That will be enough to draw all of the hardness out. During the winter the wood stove works great. Just let it cool slow. To reharden you need to know what type of steel it is. A good heat treater can do some tests (on the part/mill chips) to get a good idea, if they dont have a mass spectrograph to nail it down for sure.

 

[acmech]

Before you think about annealing the bolt, and then go through the hassle of rehardening it, look into getting some carbide drill bits.

 

[Sherman]

Thought about carbide bits but they aren't the answer here. You have to drill the bolt lengthwise twice and across once for sure and maybe twice. Also you have to tap the old firing pin insert hole and make and install a firing pin hole bushing. Guess I'll find a local heat treater and see what the cost would be to do 2 bolts, 1 spare just in case. I'm thinking about just heating it up till it glows, letting it air cool covered and see what happens. Remember, these things were made in Ruski tractor plants mostly by old fat Ruski females that couldn't read or write. Oh, but they did make 5 1/2 million of 'em. Sure caught Uncle Adolf by surprise.
Thanks for helping, Lon

 

[stanamale1]

If you try to anneal, after heating, cover completely in dry sand and let it cool.

 

[EZFEED]

I think I'll try doing a semi without waiting for these semi options being offered on some of these boards, I've looked at the build photos on Weaponeer and the MG 42 board and it doesn't seem too tough. However, when I started working on the bolt I discovered that sucker is HARD, I mean extreeemly hard. Any thoughts about how hot and for how long I need to keep it hot to aneal it so it can be worked with HSS and carbide. I can mill it with carbide for the denial block by taking light cuts and lots of coolant but I don't have carbide drills that would work.

Since this thing is a pistol cal ctg, a hot one at that, any thoughts about re heat treating after all the work is done ?? Are all of the different makes of these that hard ?? I think my kit came from OOW 4-5 years ago.

Thanks in advance for any ideas, thoughts,or help, Lon

You really only need to protect the face of the bolt. You need to isolate it while annealing the rest of the bolt with a torch.

Fill a dish up with about 1 1/2" of water and stand the bolt in it upright face down in this dish. Scribe a mark on the bolt where the water line is and have a helper add water to maintain the level as you use your torch and heat the rest of the bolt. You want to maintain a level within that upper 1/2" of water as the heat will travel down a slight bit and throw the temper a little out of whack there. It's cool because you only need the face of the bolt to keep it's hardness anyway.

Heat travels upward so only a very little bit will be affected below the controlled water line.

Works like a charm and is allot cheaper than paying someone. Pie plates work good too.

 

[Sherman]

EZ, did what you said, worked great, holes drilled, Thanks Lon

Oh, now if I can just get my MG42 to run I'll be so very happy, Thanks Again