D&T Remington 1903

[elmbow]

Hey all, I have a Remington U.S. 1903, not 1903A3, (1943 mfg) that is a sporter project. I bought it sporterized, I love sporters built on military turnbolts, and it will remain such. Nuff said on that?
I took it to my local machine shop, MGM, who specializes in T/C work but do great work on other projects as well. I am going to install a vintage Redfield receiver sight and wanted them to d&t the receiver for me. They use an end mill for the process, and they could not penetrate the hardened receiver. Of course they are not willing to pursue any annealing operations on the action and I really do not want to mess around with trying to anneal the thing. Do you guys think the Brownell's solid carbide bit is going to work?
http://www.brownells.com/gunsmith-to...l-prod719.aspx
Thanks for your replies.

[Scorch]

Carbide is about the only way to cleanly penetrate a case hardened receiver like the Springfield. It's easier to tap for the retaining screws if you anneal the receiver just in the spots where the screws will go.

[tangolima]

You can try starting the holes with diamond grinding bits, the one for dremel tools. Just need to go through the case. Much cheaper.

-TL

[tobnpr]

I did use a diamond-tip burr (Dremel type) once- these are designed to run at very high RPM (more than a mill will run), so crank it up...

I've since gotten some carbide-tipped burrs from Kodiak.

I have never heard of using an end mill to start a #6 or #8 hole- it'll walk all the way to China. Why are they not using a center drill for this? Maybe I'm missing something here...

[Wyosmith]

I have drilled many of them.

Heat the receiver to about 300 degrees in your oven.
Take a #0 tip on an Oxy-Acetylene torch and spot anneal right where you need to drill.
Turn the colors into a ring about the size of a pencil in diameter.
let it cool 100%
Now do it all again. Let the color come to the same diameter.
This will allow for normal drilling and tapping where you need to do the work, but leaves the rest of the receiver hard and strong.

[elmbow]

My understanding is these rifles are not case hardened but heat treated through and through. Not so? Seems to me though hardening would make the receiver brittle, so maybe it is a skin hardening.
Wyosmith, what is the reason for the 300 deg oven heat prior to spot annealing?

[F. Guffey]

And then there was Roy Dunlap. He published a book on 'smithing'. In his book he discussed drilling and tapping. His least favorite receiver was the Eddyston M1917, in his opinion it was anyone's guess when it came to the Eddystone.

He has an illustration of a spot 'annealer' in his book. He used a carbon torch with a 12 volt battery. I have one that is as old as his book but it was made for heavier work. The insulator for my carbon torch is a spark plug housing.

I have never found (selected) a receiver that required extra work for drilling.

F. Guffey

Forgot to add, the tape used on my carbon torch is fiber black tape. I also have a Forney carbon torch.

[James K]

A carbide bit and carbide tap can be used on those, but the carbide tools are not cheap and are very brittle and easily broken off in the hole . I have to go with those who recommend spot annealing. Done properly, it won't affect the rest of the receiver. I would never heat the entire receiver, even to 300 degrees; not only would that require stripping the receiver (not necessary for a simple d&t job), but there is a chance of getting it too hot or warping it.

I doubt they use an end mill to drill; they probably use a drill in a milling machine. I always used a jig; some claim a jig is not accurate, won't work, is only used by idiots, etc., and a milling machine is the only proper way to go. All I can say is that the jig worked for me, and takes a lot less time than setting up a milling machine, but I am sure others will educate me.

Jim

[dakota.potts]

We had a demonstration in class of drilling and tapping a Mauser receiver which also had a case harden. We did ours in a jig, pecking slowly with brand new high carbon drills. We also ended up replacing taps 3 times (they were all slightly used) where they felt to stop cutting as well to mitigate the risk of breaking.

Ours was soft enough to go through the receiver, but I raised the question of carbide drills. I was told that spot annealing is the preferable option, but carbide drills would work. Carbide is prone to breaking because of its hardness, and there is very little recourse for removing a carbide drill. A high carbon bit can sometimes be broken up with a punch to be removed from the hole. I'm really not sure what you would do if a carbide bit broke.

Hope any of that information is helpful to you.

[tobnpr]

No basis for concerns over heating a receiver to a low temperature of 300 degrees.
I do it several times a week. Cure temperature for Cerakote is 250-300
Gun Kote cure temperature is 325 degrees.

Rifles can get hotter than that just from shooting them.

I'm still trying to figure out why anyone would try to use an end mill to drill a hole in a receiver...is there a flat that needs to be milled?

[tango1niner]

While I've used a carbide ball burr in a BP to get through the "skin" I have read of using cobalt steel drills and cutting oil. Of course a rigid set-up is mandatory.

when D&T a heat treated receiver for 6-48 thds drill proper tap drill hole ( for 6-48 ) and first run a 4-48 tap in then follow up with a 6-48 tap. Taps easier...

I also prefer to use HS steel taps rather than plain carbon steel taps

[tangolima]

Originally Posted by tango1niner

when D&T a heat treated receiver for 6-48 thds drill proper tap drill hole ( for 6-48 ) and first run a 4-48 tap in then follow up with a 6-48 tap. Taps easier...

I also prefer to use HS steel taps rather than plain carbon steel taps

The minor diameter of #6-48 is 0.121", while the major diameter of #4-48 is 0.112". I'm afraid the #4-48 tap will go right through the drilled hole for #6-48, unless the hole is undersized to begin with.

I actually prefer high carbon taps. If it breaks, I can shatter it with a punch and pick the piece out of the hole.

-TL

[tango1niner]

Tangolima, you are correct. My technique would work much better using a 5-48 tap first followed by a 6-48. My bad...

concerning high/low carbon steel taps, the key is not to break them... I'm sure you'll agree.

[Wyosmith]

The reason for the 300 degree heat is that the spot annealing doesn't work if there is a fast "quench" which the cold thermal mass of the receiver itself draws the heat away from the spot too fast and does,'t allow it to soften much.
But if the receiver is at 300 and the spot goes to 800-900, the cooling of that spot is much slower and that's what causes it to soften at the place you want it to.

[Gunplummer]

Tobnpr, The reason people use an endmill is because they either do not have a carbide drill, or do not know they make them. I use them a lot to drill holes with a flat bottom. I would not try it with a drill press and it would have to be a center cutting endmill. If it is a case hardened receiver, a small spot with a carbide endmill will make sure the tap won't hit the cased area.

[tangolima]

I certainly agree. But unexpected happens even I try hard to avoid. Besides broken taps make bottom tap. Not that I try to break them.

I found drilling proper size of hole helps too. Numbered drill bits do much better than fractional bits.

I have been contemplating cobolt steel bits too. Do they work better than the high speed steel varieties?

-TL

[James K]

My only experience with cobalt bits was not gun related. I had to drill through some tough stainless steel sheet metal, and found the cobalt bits about useless, not a lot better than plain old carbon steel bits. Carbide bits cut right through with no problems.

Jim

[tangolima]

Thanks Jim. I was tempted to put down a small sum to try. No need I suppose.

-TL

[tobnpr]

I prefer HSS taps over carbon as well (Kodiak).

I've thought about dropping the coin for a carbide hand tap...if it'll eliminate the sweats when I run into one of "those" receivers, it'll be worth it to me.
Prices seem to be all over the road, from about $50-$200. Guess it depends on the alloy?
Anyone used them?

[Gunplummer]

I have never used a carbide tap in my life. I suspect they are designed for more of a wear factor than the tapping of very hard materials. Carbide does not exactly shine at low cutting speeds, which would include tapping by hand. With a high speed steel tap, you can "Feel" it flex and know when to let up. Carbide does not give much warning. Anyway, as someone already said, if you break a HSS tap there is still a chance to mill it out with a carbide endmill.
I never would work on the 03' because of the bad reputation they had. I have to agree with the poster that said they are probably more than case hardened. That is how they got the bad reputation. The post about spot annealing is probably the way to go if you want to work with them.

[James K]

I guess I don't understand. Several people with experience, some with much more than I have, have advised spot annealing, which works for both drilling and tapping with standard tools. Yet, some folks have simply ignored that suggestion and keep hoping for some magic drills and taps that will cut through that tough steel Remington used.

Spot annealing (about 1/4 inch diameter) will do no harm, will not weaken the receiver, and any discoloration will be covered by the scope bases. Pardon me, but I don't see the down side.

Jim

[Gunplummer]

Usually more than one way to skin a cat. What ever works for you.

[eastbank]

i have seen o3,s with grind mark where the tapped holes were and no heat was used. it looked like the reciever was ground with a dremel thru the case hardening and then d&t. the scope bases hid the grind marks. i don,t know which way is best. eastbank.

[tangolima]

Originally Posted by eastbank

i have seen o3,s with grind mark where the tapped holes were and no heat was used. it looked like the reciever was ground with a dremel thru the case hardening and then d&t. the scope bases hid the grind marks. i don,t know which way is best. eastbank.

It would be my preferred method.

-TL