Need a double check on my thinking. I bought a new Mauser bolt from Sarco, cut the handle off amid a shower of sparks and TIG welded a new handle on. I let it air cool after welding. Normally this leaves the stub soft enough to file. In this case the files skip off the surface of the bolt stub in the weld. I'm thinking I need to anneal it with a torch and sand treatment and finish the shaping/polishing, then harden the cocking cam notch. Make sense? Thanks

That is what I would do. Regards, Bill.

Yep

Try knocking the top off the hard spot with a grinder, it's usually not very deep, then you should be right to file.
You often get it where you finish the weld.

Be careful, the primary extraction cam is on the bolt root. If you soften it you will have to re-harden or risk galling.

I'm the same as you dpcd. I have the belt sander from hell and a I have a drawer with about 200 carbide end mills in it. Nothing much in the way of steel argues with carbide.

But on the subject of annealing. Most of the gun plumbers and jewelers I know have been using silicon micro balloons to anneal with for the last, god knows how many years. I have been using them for 20 years for sure.

Micro balloons works very much the same as using sand to hold the heat except the micro balloons transfer the heat away much more slowly than sand does which gives a better, more uniform anneal for those who lack a heat treating furnace to do it properly. Micro balloons are actually mostly air and as anyone in the window industry knows, trapped air is actually one of the poorest thermal conductors around. Be careful pulling the parts out of the balloons. Even after a half an hour, larger parts will still be hot enough to burn you and smaller parts will be uncomfortable to the touch. 20 minutes to 1/2 hour is usually long enough to allow the part to become thoroughly softened.

Here's a video of it but lets face it, annealing is not really a show me sort of thing required. Heat, plunge, wait then rework part as required. It is sort of fun watching the micro balloons boil for a half hour.

ADD NOTE: Plunge the part deep enough into the bucket of powder so that the micro balloons don't boil to the surface. That way an insulating cocoon of dry micro balloons will form around the part. You can NEVER get all of the moisture out of micro balloons. Even if you cook them in the oven there will still be moisture in them and as they cool they will suck moisture back in until they hold the same amount of water as the air around them.

https://www.youtube.com/watch?v=pOntsvBKvKk

Well, I learned something today.

OK, I guess I was the 27th person to watch the video. Actually, it was interesting. Better than watching cute kitten videos or the other tripe on the internet. What were you annealing the screw for?

quote:

Here's a video of it but lets face it, annealing is not really a show me sort of thing required. Heat, plunge, wait then rework part as required.

You didn't read the disclaimer above. You were warned ! Annealing is only SLIGHTLY more interesting than watching frolicking kitten videos.

When you anneal screws the teeth don't break off the dies when you extend the threads.

quote:

Originally posted by dpcd:
Well, I learned something today.

You aren't alone. Neat stuff!

Thanks guys - I had to touch up a few small places in the weld and let it air cool. Now the stub is as soft as the handle. Strange. I guess I inadvertently tempered it.

Just like watching grass grow....