Having trouble with a pin and weld with surefire muzzle devices.

[i556]

Hey guys , can anyone recommend me a good drill to get through sure fire muzzle devices and a nitrided barrel. Ive tried with two high speed bits, one of them being a cobalt bit and I cant make a dent in it. Does anyone have any recommendations or tips for me. Any help would be greatly appreciated, ty

 

[Ex E6]

IF You have to drill it ; Tungsten carbide bit . Make sure your setup is solid and Don't allow bit to chatter carbide doesn't like that . USE cutting oil and NOT lube oil .

 

[papershredder]

Ideally, you want to use a cutting tool that is sized perfectly to the pin that is being drilled. Are you using a drill press, milling machine, or hand drill? Regardless, carbide is your best option. Plunging an endmill through the weld is better than trying to use a drill. Drills have a tendency to walk off center and chew up your work piece if everything isn't lined up perfectly. Even then it could still happen even if everything is aligned. You want to use a vise as well, don't try holding the barrel with your hand while drilling. If you have a mill or drill press, plunging a carbide end mill is the way to go. Make sure your spindle can do at least 1500 rpm's. Faster spindle speeds are preferred when using carbide. If a hand drill is your only option, then get a carbide center drill along with a carbide drill. Use the center drill to start your hole. Make sure it is centered and straight as perfectly as you can get. Once you have the hole started, switch to the drill, again keeping everything perfect and straight. Also invest in a thread file just in case you don't drill perfectly straight.

 

[i556]

Thank you paper, unfortunately I am using a handrill. I do however I am using a vice and the warcomp is pre drilled so im a bit lucky there. Ive done 2 muzzle devices before and never had a problem getting through, but maybe its because they were cheap or had poor heat treatment or nitriding. The hole is 5/64 and i kind of wanted to drill through and then tap and thread it and use a set screw as the pin, but given how hard the metal seems its deterred me. im gonna get 2 carbides tomorrow , ill get a 1/16 and a 5/64th do I need to lube it as i drill?., I thought i was going crazy as the cobalt bits didn’t even make a dent, what do you think of the set screw idea? Anyhow I greatly appreciate your help , Ill let you know how it goes

 

[Kadams1563]

I would definitely recommend finding a drill press to use. Cut using cutting oil.

I mark the depth I want to go on the drill bit. Cut through the brake and into the barrel until I hit the mark. Chaos the back of the drill bit off, put it in the hole, and tack weld over it.

 

[Aftermath]

I use the bit I made the hole with as my pin. As has been stated, use a drill press. Once I have the bit to depth, I pull the bit, use a larger bit to chamfer just a little, then put the original bit back in the press but reverse it so the smooth end is going into the hole, push it in and lock the drill press into that depth so it can't back out. Then I TIG weld it, using the extra bit as the filler rod as it melts. You don't need a big glob, just a small puddle. My best ones don't leave the chamfer much. I don't clean it up either, leaving the weld obvious to those whom it may matter.

 

[lariat]

Others have said it, use a drill press or suffer the consequences. Using a hand drill is probably the cause of a big part of your drill bit problems. But I guarantee you it will be the cause of your future enlarged hole problem.

Put it in a solid setup in a drill press. There are a couple good ways to start the hole for the drill - endmill (if properly sized) or spot drill. I prefer spot drill.

If you don’t have a drill press I would take it to someone who does.

 

[redbullitt]

Just be glad it's not one of those near unobtainable "legacy" muzzle devices they fucked us with... then you'd really be shitting your pants to preserve it lol.

Seen those SS ones go for 600 plus .. : (

 

[i556]

Ok copy, i will find a press , i just ordered the bits.

 

[papershredder]

Thank you paper, unfortunately I am using a handrill. I do however I am using a vice and the warcomp is pre drilled so im a bit lucky there. Ive done 2 muzzle devices before and never had a problem getting through, but maybe its because they were cheap or had poor heat treatment or nitriding. The hole is 5/64 and i kind of wanted to drill through and then tap and thread it and use a set screw as the pin, but given how hard the metal seems its deterred me. im gonna get 2 carbides tomorrow , ill get a 1/16 and a 5/64th do I need to lube it as i drill?., I thought i was going crazy as the cobalt bits didn’t even make a dent, what do you think of the set screw idea? Anyhow I greatly appreciate your help , Ill let you know how it goes

@Aftermath in post #6 has the better idea. As for using a set screw as a pin, I wouldn't. You'll still have to weld the set screw, which will make the threads unusable, you'll have to drill the set screw out should you decide to change out the muzzle devise again.

 

[i556]

Thank you guys so much, im through the muzzle device and getting ready to go into the barre.Im gonna do the same as @Aftermath forsure. As far as the depth into the barrel should i go for a 10th of an inch, its 1/2*28 threads?

 

[Aftermath]

Thank you guys so much, im through the muzzle device and getting ready to go into the barre.Im gonna do the same as @Aftermath forsure. As far as the depth into the barrel should i go for a 10th of an inch, its 1/2*28 threads?

What is the barrel OD and the groove ID?

 

[Aftermath]

Really, if you just go to the bottom of the barrel threads and then a hair more, you are good, no matter the threading.

 

[lariat]

Really, if you just go to the bottom of the barrel threads and then a hair more, you are good, no matter the threading.

Agreed. But OP I have a question: do you know the major and minor of the thread you have on the barrel? Until you know it you can’t utilize this info.

I’m not trying to be an ass. It’s a serious question.

 

[Aftermath]

It's really not rocket science and no need to get to machinist about it either. Drill the muzzle device through, clean it up a little, look at the barrel threads and make an educated guess at how much more to the bottom of the threads, screw it on the barrel, place in a vice on the drill press, touch down and go that little bit more. Then pull it up, put in a bigger bit, cut it a little bit, pull that bit and put the little one back in upside down. Push it. Push it real good. Lock it in. TIG.

I mean, I actually get a little more machinist about it all but I tend to be a perfectionist and the engineer can't stay out of the way for very long at all. But it really isn't too crucial unless you drill all the way into the bore.