P14 drill/tap problems

[kell2784]

Seems a Win P14 is turning out to be a stubborn piece of metal, and eating drill bits like free snacks. I know these things are hard and tough, but an ERA must be absolutley horrendous. I guess my next step is to try a machine shop, and have them re-temper after drilling.
Any suggestions gunsmiths?

 

[smoji]

Use a cobalt drill.

 

[BwanaDave]

take a dremel to it, just enough to get past the hardening then drill and tap away

 

[kell2784]

The gunsmith used cobalt bits. That is why I (and him) are scratching our heads.

 

[kell2784]

There is actually a little point of material removed already from the previous drill attempts. I would think we would be past the hardening.

 

[KyleSchenk]

Either a solid carbide drill (not a concrete drill) or end mill will do it.

 

[m39a2]

Cobalt will drill the hole but you will break off your tap. That will be tough to get out!
Scott

 

[3screwsloose]

tough drill and tap

I had heard my dad's machinist friend back in the mid 80's used to heat up a small allen wrench with a torch, and touch it to the receiver spots where he was going to drill and tap, I'm guessing to soften up the surface. He used to curse up and down about the swedish mausers he was "sporterizing" back then having so many broken bits.

 

[maple_leaf_eh]

The old time gunsmiths like Dunlap knew what to do. What I remember ... was to spot anneal the receiver to remove the extremely hard temper. How you do that I couldn't tell you.

 

[guntech]

Seems a Win P14 is turning out to be a stubborn piece of metal, and eating drill bits like free snacks. I know these things are hard and tough, but an ERA must be absolutely horrendous. I guess my next step is to try a machine shop, and have them re-temper after drilling.
Any suggestions gunsmiths?

It can be a ##### of a job to correctly locate, and drill and tap. Sharp new bits and taps are needed.

If your drill speed is too fast and your feed to slow it is real easy to work harden that spot and burn your bit.

I would suggest drilling the hole with a carbide bit. Leave the action set up in the drill press - don't move anything. Then with an acetylene torch and a small tip, heat as quick as you can one hole past a blue draw. Don't over do it.

Then using a new ( there is nothing sharper) starter tap, start tapping that hole with the tap in the chuck, turning it by hand as you would a tap handle. Once you get it started switch to a new plug tap and continue deeper. Make sure you use a good cutting oil and go easy. Switch to a new bottoming tap and continue. You may have to quickly heat the hole a couple of times before getting it right. You don't want to reach much past a blue draw and you don't want other parts of the action to experience this.

Doing this in the drill press really cuts down on tap breakage.... and that's another story.

 

[bearhunter]

3Screwsloose has the right idea, and it works very well. I doesn't need to be an allen wrench though, a 4in common nail will do nicely.

first make a mark of some sort. Usually a centerpunch will make an indentation that is adequate to rest the nail on the spot to be softened.

While holding with a pair of vice grips, heat the nail or allen wrench up to cherry red and hold it on the spot to be softened. Keep the nail at cherry red with a propane torch, being careful not to get the flame on the receiver. After a very short time, the receiver will begin to turn red around the nail, just a small area, only slightly larger than the nail.

Lift the nail from the receiver and there will be a perfectly round bright red spot. It will only last for a few seconds, but that spot will have changed color and once cool, don't quench it with anything just let it cool on its own, it will be fairly easy to drill and tap.

The rest of the receiver will be as original.

By the way, if you're going to soften the whole receiver, unadvisable, by the time it is reheatreated, you might as well go out and by a finished factory sporter receiver when the costs are all added up. bearhunter

 

[josquin]

...
Then using a new...starter tap, start tapping that hole with the tap in the chuck, turning it by hand as you would a tap handle...

À propos of this, I came across the B-Square piloted tap handle in the Brownell's catalogue, but stopped looking when I saw the price ($78.82) However, I see that Busy-B Tools also has one (1/16" - 1/4" cap.) for about $15.00:

At that price it likely (!) isn't the quality of the B-Square one but it would probably do the trick. I made my own by drilling out the shaft of an old tap handle I had lying around and using a bit of steel rod for the pilot. It certainly makes tapping a straight hole a lot easier.

Stuart

 

[kell2784]

Damn, that's a great idea, simple too.
I think I'll give that idea a try where after drilling the hole, I'll remove the bit, and insert the tap in the chuck, and slowly thread the hole by hand. (Not moving the receiver or vise at all)

Also: should I be concerned with annealing the receiver to a hardness of 35 to 40 on the C scale after drilling and tapping is complete. I haven't had it tested yet, but I think it is way past that now. I really don't know the exact composition of the receiver yet, except that the carbon content must be fairly high.

 

[BwanaDave]

Kell, I think it must be high carbon content steel as well to be that hard. When I drill monel rivets at work I usually dip my drill bit into beeswax (enough to fill the flutes for the first 1/2") and as it heats the wax liquifies and wicks some of the heat away , I then re-apply . It makes the difference between being able to drill 100 or 1 rivet before the drill bit is ruined . Just thinking maybe you should give it a try. Maybe try spot annealing the centerpunch marks with a small small tip in the oxy acetylene momentarily .
Dave

 

[josquin]

... When I drill monel rivets at work I usually dip my drill bit into beeswax (enough to fill the flutes for the first 1/2") and as it heats the wax liquifies and wicks some of the heat away , I then re-apply . It makes the difference between being able to drill 100 or 1 rivet before the drill bit is ruined. Dave

Hmmm... I wonder if Heat Stop Paste (like the stuff Brownell's sells) would work even better? (Assuming it isn't abrasive.)

Stuart

 

[Bob Morgan]

Best to poorest-Take a car battery, hook a heavy wire to one terminal and other end bolted tightly to tang bolt hole of receiver,hook a heavy wire to the other terminal attach it tighly to a pointed piece of carbon or copper,hold this piece with a pair of padded vicegrips and touch the point to the spot to be anneald.OR smear action with a 1/8" coat of heat stop paste,leaving bare spots to be anneald ,heat with a small tip acetylene torch. OR use wet asbestos instead of heat stop paste,wear a dust mask so you dont breath in the asbestos fibers.Have used all the above and they worked fine.