Removing a broken tap

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canucklehead

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Hey guys,

Well, I'm up the creek.

I JUST received a 6/40 tap in the mail in order to complete mounting my Wilson Combat ghost ring sights... and while tapping the front hole (right through receiver), the tap SNAPPED off, and now the tap is stuck in the hole.

It is a tri-fluted bottom tap, and it is just coming out the bottom, but the top is broken almost exactly flush with the top.

Any easy way to remove this? Best left to gunsmith?

ARGGGGHHH!!! I'm really pissed now. The tapping was going perfectly, and then snap. What a piece of junk!!!

Anywho, any suggestions would be GREATLY appreciated!
 
If you can get to both sides of the broken tap, try using a flat bottom punch and strike the tap from both sides. Start gently. You may loosen up the threads enough to allow you to back off the tap with a pin punch from the front.

Even if you don't have proper tapping fluid, anything is better than nothing.
 
canucklehead said:
Hey guys,

Well, I'm up the creek.

I JUST received a 6/40 tap in the mail in order to complete mounting my Wilson Combat ghost ring sights... and while tapping the front hole (right through receiver), the tap SNAPPED off, and now the tap is stuck in the hole.

It is a tri-fluted bottom tap, and it is just coming out the bottom, but the top is broken almost exactly flush with the top.

Any easy way to remove this? Best left to gunsmith?

ARGGGGHHH!!! I'm really pissed now. The tapping was going perfectly, and then snap. What a piece of junk!!!

Anywho, any suggestions would be GREATLY appreciated!
Click to expand...


First thing you can try is to mount the reciever in a vice,then use a center punch against one of the flutes.Tapping lightly with a hammer CCW and it will usually come out.If it's stuck really hard a diluted solution of nitric acid may help,or you could drill it out with a small carbide drill.The drill diameter should be slightly smaller than the minor diameter of the bolt size.
 
Thanks for the tips guys. I was using oil while tapping... would that be different than cutting fluid?

Either way, I tried using a carbide tip on my dremel to make a slot in the top (read it on the web), but the hole is too small to make a good accurate slot for a screwdriver.

I will try to back it out with a punch and hammer first... if that fails, I'll guess I'll drill it out.

Any idea what a gunsmith would charge to get it out an re-tap? I shudder to think....
 
First of all is it a high speed steel tap or a carbon steel tap? If its carbon steel you can chip it out a bit at a time with a good center punch. If it's high speed you can't.

If you have a very fine pair of needle nose pliers you may be able to get on the tip and turn it back out from inside, (you said it was through right?)

If it's through the hole in the bottom, worst case is driving it through with a small punch and hammer. Before you go that route though, here's a few tricks to try.

First try to pick/blow all the chips out of the flutes so you can see light down all of them. Get a small sharp center punch and try to GENTLY tap it back out in a counter clockwise direction, your unscrewing it with the hammer. Gently does it, and make sure not to hammer up the top of the hole, if you peen the top thread over on a little tap like this your done.

If that dosen't work, or it moves a bit but you can't tap it back out, find some fine steel wire you can thread down each flute. Twist it together with pliers top and bottom and see if you can use it to turn the tap out (probably best to back out). This is a poor mans tap extractor and generally works just as well, spring wire or music wire is best.

If you get a small enough carbide drill you can carefully drill it out. This is not a hand drill job, because if you go off center you'll drill down the side of the hole instead of the tap. Vice and drill press or mill in a perfect world. Be very light on the pressure as carbide is brittle, don't let it grab, it'll snap trust me.

If you have steady hands you can grind the center out of the tap with a diamond or carbide burr in a dremmel tool, but stay on the tap, it's easy to slide off into the reciver. A little notching won't hurt but it will look like hell ( on the bright side it will be hidden under the sight, great sights by the way, I've got a set on myself)

Keep me posted. Where are you? If your close maybe it can go to work with me and I'll take it out on my mill.

Good luck. Don't get rammy, be gentle, have a beer, stay calm. 99% of the time you can get these little buggers out if your patient.
 
You didn't only use a bottom tap, did you? I mention this because you mentioned that it was a hole through the reciever, for which I would have only used a tapered tap. There is no reason to use a bottom tap unless you need to, and plenty of reasons not to if you don't.

Anyway, getting the broken tap out: Frankly, if it was me, I would take it to a gunsmith to mess with. For the time, frustration, and potential to f**k it up, it's worth it to me to pay someone else to do it. Unless it's your goal to become a gunsmith.
 
Wow, didn't expect THIS many responses!!!!

Thanks for all of the tips. Using the method described here:

"If you have steady hands you can grind the center out of the tap with a diamond or carbide burr in a dremmel tool"

...and it worked!!!

I initially tried to back it out with a punch, but after realizing that when working from the bottom, I need to go CLOCKWISE, and from the top, counterclockwise... heh heh..spent an hour fighting against myself...

The little diamond ball on the dremel worked perfectly! Didn't think it would work, but the hole rethreaded perfectly. Man was I stressed for a bit! I have the tendancy to be rammy, so I'm suprised I did it okay!

Thanks again for all the help! I think at one point this topic had 6 views and 5 replies... that shows the knowledge base of CGN is a poweful tool! Thank you for the tips.

The reason I used a bottom tap is because there are two holes that needed to be tapped, and one IS blind, so I figure get the one tap that should do both!


Now the problem... the screws supplied are too short! It's a Norinco frame, and I seeing from comparing it to my real 870 that the little depression a fre inches back from the front of the receiver is deeper on the Norinco. Too flipping short!!! ARGH!!!! :)
 
Glad you got the tap out. Broken taps are a misery. The bottoming tap is used only on a blind hole after the hole has been tapped as far as possible with a taper or plug tap. Incidentally, you can grind your broken tap to make a bottoming tap.
Use cutting oil, or products like Tap Magic, Flute Juice, etc. Different lubes for different materials, steel, iron, aluminum, etc. In a pinch, spit will work.
OK, I've got to ask - is 6-40 the correct tap? The reason I ask is that 6-48 is overwhelmingly the most common thread for sight installation. I've never had anything to do with the Wilson sight you are installing, so I cannot be sure.
Longer 6-48 screws are easy to get. 6-40s should be available from a serious industrial hardware outlet.
 
tiriaq said:
. Incidentally, you can grind your broken tap to make a bottoming tap.
.
Click to expand...

You can do T, but be careful on the regrind. Alot of the time you end up with a partial tooth on one or more flutes that snaps off and jams the tap. I do what you say as well, but only as a last resort, and never in a blind hole.
 
tiriaq said:
OK, I've got to ask - is 6-40 the correct tap? The reason I ask is that 6-48 is overwhelmingly the most common thread for sight installation. I've never had anything to do with the Wilson sight you are installing, so I cannot be sure.
Click to expand...

Sadly, yes. The instructions are very specific about a #33 drill bit and a 6/40 tap.

It is pretty rare (well, maybe just an oddball), as you sure can't find EITHER of those things at any Home Depot/Crappy Tire/Rona type place. Even house of tools doesn't sell them!
 
canucklehead said:
Sadly, yes. The instructions are very specific about a #33 drill bit and a 6/40 tap.

It is pretty rare (well, maybe just an oddball), as you sure can't find EITHER of those things at any Home Depot/Crappy Tire/Rona type place. Even house of tools doesn't sell them!
Click to expand...

6-40 is more readily available from industrial sources than 6-48, which you don't commonly see.

I've bought 6-40 screws locally before. If you get into the northeast, Calgary Fastener or Triad might have a tap. Give them a call first though, because both usually have PITA queues when you get there.
 
6-40 is simply a UNF thread should be common, 6-48 isnt a UN series thread making it less common.

I wonder why they just dont use 6-32 UNC as I've seen this one the most. :)

Dimitri
 
Dimitri said:
6-40 is simply a UNF thread should be common, 6-48 isnt a UN series thread making it less common.

I wonder why they just dont use 6-32 UNC as I've seen this one the most. :)

Dimitri
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:) Although that would be nice from an availability stand point, some of those sight screws are mighty short and the 34% greater tpi on a 6-48 is a considerable advantage in fastening ability over 32 when you are talking about screws that small.
 
SPI,

Perhaps you are right, still I'd have stuck with a 6-40 if not a 6-32 instead of the 6-48 as it would be cheaper to get the tooling set up for it :)

Dimitri
 
Oh, yeah, no question that if I was designing a part I would try to use commonly available components, but since 6-48 is common in the firearms industry it would be reasonable, and often advantageous, to use it for attaching sights.
 
tiriaq said:
, Flute Juice, etc. Different lubes for different materials, steel, iron, aluminum, etc. In a pinch, spit will work.
.
Click to expand...

The absolute best lube for tapping and reaming steel that I have found is beef tallow - available at your local grocery store. For aluminium, water with just a hint of dish soap.
 
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