Drilling and Tapping Hard Metal

[Minshooter]

If you do get it done, would appreciate seeing what you did to the safety.
Thanks

 

[338 Mollett]

Heres why i only use hss taps. They are good for one hole, maybe 1/2 hole. Once they start clicking, replace asap. I only used carbide taps in production and always had a tap burner edm on standby. Wish i had one around now as i sit with a broken 8-40 in an action View attachment 1390639

Same guys making your truing bars I am pretty sure can burn that out.

 

[Dusty Stevens]

Same guys making your truing bars I am pretty sure can burn that out.

Id love to drive it on over

 

[DR_2297]

I foresee a new post “how to remove broken tap”. Take it to someone experienced in D&T hardened materials. If it is through hardened especially!

 

[hogpatrol]

I foresee a new post “how to remove broken tap”. Take it to someone experienced in D&T hardened materials. If it is through hardened especially!

If they were over 3/4", I used an o/a torch and ice water. YMMV.

 

[Steve morgan]

If they were over 3/4", I used an o/a torch and ice water. YMMV.

Carbide drill & cnc edm sinker to thread the hole. Know a shop that does this, works well.

 

[Steve K]

There is a lot of good information here, some contradictory. Should the rpms be high or low for a carbide or cobalt bit? I'm not a machinist and only have standard workshop tools and machines. I think I will ask a gun club member to lend a hand since he is a machinist; should have thought of that sooner.

 

[Dusty Stevens]

There is a lot of good information here, some contradictory. Should the rpms be high or low for a carbide or cobalt bit? I'm not a machinist and only have standard workshop tools and machines. I think I will ask a gun club member to lend a hand since he is a machinist; should have thought of that sooner.

Always slow with pressure. The more you let a bit spin the harder the material gets

 

[WSnyder]

I wouldnt use a carbide tap on anything. Use a good quality hss tap, 2 or 3 flute, made in usa. If you use carbide only an edm will get it out

That Electro-Arc machine sitting in the corner sure comes in handy now and then

I think I will ask a gun club member to lend a hand since he is a machinist; should have thought of that sooner.

That's probably a good idea because using carbide outside of a mill is generally asking for trouble. A mill will hold it rigid and allow you to peck at hard materials in a controlled manner and keep from breaking things.

 

[Pawnee Bill]

Ask the old timers how they drilled and tapped Springfield receivers.

 

[DR_2297]

Ask the old timers how they drilled and tapped Springfield receivers.

Well I don’t know about them but I use an 1/8” carbide endmill and high quality 3 flute tap. I get about 2 receivers a tap… once you get through the case it is easy cutting until you hit the other case surface. Key is don’t force if and use high quality HSS tap and a lot of cutting fluid. Keep the tap perfectly straight (plunger in quill into tap handle center).

 

[akajun]

Ask the old timers how they drilled and tapped Springfield receivers.

Spot annealing or grinding away the case
Then normal hss

 

[skeeljc]

Start with a carbide center drill and go deep enough to break through the surface hardness to the diameter of the tap drill. Drill the hole with something better than HS steel. You might want to consider drilling with the carbide center drill from the opposite end to get through the surface hardnedd. Then tap with a 3 flute tap. All this should be done in a mill, not a drill press.

I used to drill and tap Ruger .22 auto pistol bolts for a charging handle.

 

[Sniperhandle]

Heres why i only use hss taps. They are good for one hole, maybe 1/2 hole. Once they start clicking, replace asap. I only used carbide taps in production and always had a tap burner edm on standby. Wish i had one around now as i sit with a broken 8-40 in an action View attachment 1390639

Dusty, I just removed a broken HSS tap on my Mill with a solid carbide end mill,I bought the rec for cheap because it had a broken 3 flute 6-48 HSS tap in it, The end mill went through it like it wasn't there, If the tap would have been carbide, You can break carbide taps out with a good hardened punch because they will shatter, Not so with HSS. I dont use HSS for drill and tap anymore at all, Carbide just works so much better.

 

[gunsandgunsmithing]

Dusty, I just removed a broken HSS tap on my Mill with a solid carbide end mill,I bought the rec for cheap because it had a broken 3 flute 6-48 HSS tap in it, The end mill went through it like it wasn't there, If the tap would have been carbide, You can break carbide taps out with a good hardened punch because they will shatter, Not so with HSS. I dont use HSS for drill and tap anymore at all, Carbide just works so much better.

HSS will break up too but not as hard as carbide, by a long way. I just buy several good carbon steel taps for gun work. Sooner or later, they all break but getting the carbon steel one out is a lot easier. They'll cut just about anything that hss will if they're both sharp. I don't have an edm so I do what makes life easiest WHEN Murphy comes calling. Carbide is very unforgiving but it'll cut carbon steel taps right out. I don't use many hss taps at all, on gun stuff. Hss lasts longer but I find it doesn't cut much that carbon steel won't cut. It's just not worth the trouble. I just buy more carbon taps. They're cheap and cause less migraine kinda headaches. Just my 2 cents worth. But remember, I'm the guy that has to get your broken tap out when all else fails..please.
Dusty, I don't think I charged you anything but the shipping for getting yours out. Yes, I took forever but I usually charge based on a scale...carbon is the cheapest, then hss, then carbide. It's not a linear scale!!! Lol! Best I remember, it wasn't bad.

 

[Dusty Stevens]

HSS will break up too but not as hard as carbide, by a long way. I just buy several good carbon steel taps for gun work. Sooner or later, they all break but getting the carbon steel one out is a lot easier. They'll cut just about anything that hss will if they're both sharp. I don't have an edm so I do what makes life easiest WHEN Murphy comes calling. Carbide is very unforgiving but it'll cut carbon steel taps right out. I don't use many hss taps at all, on gun stuff. Hss lasts longer but I find it doesn't cut much that carbon steel won't cut. It's just not worth the trouble. I just buy more carbon taps. They're cheap and cause less migraine kinda headaches. Just my 2 cents worth. But remember, I'm the guy that has to get your broken tap out when all else fails..please.
Dusty, I don't think I charged you anything but the shipping for getting yours out. Yes, I took forever but I usually charge based on a scale...carbon is the cheapest, then hss, then carbide. It's not a linear scale!!! Lol! Best I remember, it wasn't bad.

Yes it spun right out. Now i have a hss tap broken in a hardened action. The omegadrills will get hss taps out easily i just gotta get back on it. Its broken at about a 45deg angle under the surface and its a 4 flute. I have a tool to remove a 3 flute thats real slick. The angle its broken is whats messing me up. Ive chipped 2 carbide end mills on it so far

 

[gunsandgunsmithing]

Yes it spun right out. Now i have a hss tap broken in a hardened action. The omegadrills will get hss taps out easily i just gotta get back on it. Its broken at about a 45deg angle under the surface and its a 4 flute. I have a tool to remove a 3 flute thats real slick. The angle its broken is whats messing me up. Ive chipped 2 carbide end mills on it so far

Hard to say without it being here but I'd start by squaring it up and milling it out with a carbide end mill. You might be able to square it up enough with the chipped carbide end mill and go from there. That omegadrill might work then. Don't know without seeing or just putting a cutter to it. Good luck. The one I did for you didn't spin right out but cut with carbide, IIRC. Either way, I got it out. I just can't remember what I did yesterday, much less then. You'll see one of these days. Lol! I've tried those broken tap extractors a few times. Might work about 2 out of 10 times, ime. Maybe better on a little larger stuff but I've had poor luck on small taps. The old way still works most of the time...break it up into little pieces.

 

[ridgeway]

I'll take a worn carbide endmill and grind a spade on solid shank size and drill out a tap web. Cylindrical grid the diameter to fit your needs. Usually I
start off with a new endmill to make the ragged tap flat first

 

[Steve Blair]

If you manage to drill a hole and when you break the tap, a competent EDM shop can remove the broken tap and tap the hole, regardless hardness.

 

[gunsandgunsmithing]

I'll take a worn carbide endmill and grind a spade on solid shank size and drill out a tap web. Cylindrical grid the diameter to fit your needs. Usually I
start off with a new endmill to make the ragged tap flat first

Not necessarily relative to your post but carbide depends on heat more than sharpness. It will stand way more heat than hss or carbon steel. You can just about met a hss tap out against a dull carbide cutter. Not saying it's the best approach but the difference in heat both can stand are drastically different.