Springfield O3A3 drilling

I'm having a hard time spot annealing a U.S. 1903A3 reciever for drilling and tapping. I use the radiused rod, 3/8" od, tinned for better heat transfer, heated red hot and brought down on the spot to drill method. Left to cool, slowly, I drilled and tapped 2 of the 3 holes like this. But the forward most hole, next to the barrel, is staying hard. I've done Springfield and Enfield recievers before this way but this one has me flummexed. I tried using a half inch rod for more heat transfer and slower cooling but that didn't work. There's more metal under this hole, barrel shank, so heat transfer is different. Any thoughts or new ways to do this are appreciated.

For putting the hole in, how about using a solid carbide slot drill?

That doesn't put a thread in the still hard as hell hole though...

Alpacca Fortyfive said:

For putting the hole in, how about using a solid carbide slot drill?

That doesn't put a thread in the still hard as hell hole though...

Click to expand...

Once you get through the initial hard stuff with a carbide drill, tapping is not so bad, just keep it wet with tapping fluid, go slow, and turn the tap back and forth slowly and don't force it.....

The 1903A3 Springfield action was made of Chrome-molybdenum steel, and is not case hardened. It should drill and tap with SHARP HSS or cobalt tooling if you have not spot work harden it by spinning a dull drill on it. You should be using something like Easy tap for a cutting fluid. If you have work hardened it, a solid carbide drill should solve your problem. Trying to spot anneal the steel was a trick used on the earlier Double heat treated 1903A1 actions that were case hardened. However, breaking through the case with a solid carbide drill is most likely a better way to go about that also. Gary P. Hansen

carbide drill

yep a carbide drill is the only way to go. tapping is not bad there after.

Well I got it. Maybe I had work hardened it because HSS just wouldn't cut it. I had a brand new carbide 1/8" drill so I figured the extra 5 thou would be a little easier to tap, a 6-48 thread calls for a #31 drill which is .120". I also used a new tap and it went pretty well. I'll be sure to loctite things well to take care of that little extra thread clearance. Thanks for knowledge.

actually the drill is your minor diameter. there shouldn't be no play between tapped hole and setscrew unless your tap is oversized.

Easy way to aneal for tapping

Drill the hole with a carbide bit, the heat a pies of proper dia. drill rod, stick in the hole and tapping is a breeze. Anneals a much smaller area than any other method.

Duane's Gun Repair

Actally if you have a TIG or an oxy/acetylene tourch its insanly simple. Buy some 3/8s copper rod and lop off a cookie 1/2 inch long. Put the cookie in the lathe and turn a quick .121 x .121 plug at one end. Drill the hole in the receiver with a #31 carbide spade. Drive the turned end into the hole and hit it with the torch. The TIG of course is much faster and you don't have to worry about the copper welding to your receiver by accident with either torch. After you get it to the temperature you want, let it cool with the plug in the hole. Knock out the plug and tap the hole with lots of wiener slider. Copper draws, holds and most importantly, transfers heat remarkably well. Go figure that they would make silly things like soldering irons and cook wear out of it.

To Add: Leaving the plug in the hole will allow the steel to cool slower and generally seams to leave it softer. I generally take the plug to red, hold it there for a minute or so and walk away for 5 minutes.