Drilling and Tapping Hard Metal

[Steve K]

I'm trying to modify the safety lever on a Sig Trailside. I would like advise on how to drill the hole in the safety. I've tried using a variety of drill bits including tungsten, cobalt, black oxide and others, nothing works. I'm using a drill press at 1,100 RPMs and only get a minimum of penetration. I want to drill through the lever and tape it for a 6-32 screw. So far I've only scratched the surface. Is there another bit and speed combination?
Thanks in advance for your suggestions.

 

[gunsandgunsmithing]

if you can't drill it with carbide, you're nighmare has only just begun. Find another plan. A harder tap is NOT the right plan. They just break easier and are harder to get out.

 

[Twdmar]

Have you ordered a new safety if you wreck the first one? Perhaps it just had a hard coating that could be ground off and you could drill, but there is no guarantee it's not just a very hard part. If you get a tap stuck in there you'll have a big problem.
You could maybe spot aneal it if you're just looking to drill at the end of the tab.
Another possibility is it's some kind of MIM part and that could give you other problems.
As was previously mentioned, you might just have to live with it.

 

[Dusty Stevens]

Id try more pressure and waaay slower speed. All you do with 1100rpm is harden it more.

 

[Sniperhandle]

Id try more pressure and waaay slower speed. All you do with 1100rpm is harden it more.

This ^^^^, You have work hardened it now, You did not list "Carbide Drill Bit" as being one you have tried, A Carbide bit should go through it like "Butter" But they break easily and are expensive. You will also need a carbide hand tap.

I have drilled and tapped receivers that were harder than "Woodpecker Lips" with carbide.

 

[ridgeway]

Carbide will drill it like butter. Then run in a 6-32 carbide tap. I'm not so sure your looking to spend that kinda money on some sort of modification to a safety. What's the problem with it?

 

[Sniperhandle]

Once you get the carbide tools, Also use "Tap Magic" for the drill and the tap.

 

[DiffEQ]

Once you get the carbide tools, Also use "Tap Magic" for the drill and the tap.

And if you can't find Tap Free or Tap Magic, a welding "anti spatter" spray should work nicely.
Modifying a safety lever? Should everyone stand back when you pull your Sig out?

 

[USMCDOC]

And if you can't find Tap Free or Tap Magic, a welding "anti spatter" spray should work nicely.
Modifying a safety lever? Should everyone stand back when you pull your Sig out?

Anchor lube

 

[akajun]

Once he drills it with carbide, unless he has a mill and buys a carbide tap how’s he gonna tap it? Look up spot annealing, do that, quality cobalt bit, good lube, and slow the speed way down

 

[MClark]

EDM the hole slightly oversized.
Fill hole with brass braze.
Drill and tap hole.

 

[hogpatrol]

If you can't get a carbide tap drill, use a 7/64 carbide two flute end mill. I'd use a three flute/gun tap too.

 

[Dusty Stevens]

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

 

[jackieschmidt]

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

Dusty, a HSS tap will not cut a case hardenned part or a part that is hardened all the way through,
Used correctly, a tungsten carbide drill will drill things up to 60RC.

The catch is, “if used properly”. That means a very rigid set up and high RPM. A rigid setup means secured in a milling machine, not a drill press, using the shortest drill you can get by with.

As with a lot of things, a little common sense will go a long way. In short, you have to know when things are going right, or wrong.

 

[ridgeway]

I think the bigger question, why in the world is the OP looking to modify a safety?

 

[Walt Krafft]

I did this to some AR15 bolt stops. Hard as woodpecker lips mim material. EDM the hole and threads. That is the only way.

 

[Ray123]

Tungsten carbide drill or end mill will cut it...but its brittle, no bouncing or chatter, like the usual drill press, with sloppy spindles & crappy bearings it will chip and break the carbide.
I used to mill out broken 10X24 taps in thick copper parts with small carbide end mill...there was never a broken tap that was not removed the material that was $600 each, for a blank part, so ya find s way. I did it in a CNC mill, indicated the part, checked the program & found the exact center, and then went manual... by using the manual hand wheel feeding in ten thousands of an inch, at 1800 rpm no coolent ... slowly feed the hand wheel on the control panel...set on ten thousands increments. It's a feel thing ...you have a mill that weights tons, a huge spindle, and a tiny carbide end mill in the collet, but it will let you know by feel and sound, as to how it's cutting...the heat generated helps take the heat treatment out of the tap, softening the hard tap material as it mills down.

 

[Herzo]

Carbide drills need to be run fast! I would run a #36 drill at least 2500 RPM with plenty of coolant (cutting oil). If you are dealing with hardened steel, it would not hurt to go larger with your drill say a #34. That would aid in tapping and you would retain adequate strength.

 

[paperpuncher]

EDM the hole slightly oversized.
Fill hole with brass braze.
Drill and tap hole.

I am filing this little beauty away. New trick for this old dog Thanks

 

[Dusty Stevens]

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