Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
BCM
User Panel

Page AK-47 » Build It Yourself
AK Sponsor: palmetto
Site Notices
Posted: 6/24/2008 2:36:08 PM EDT
Its a #10 hole, so do I drill it out with a 1/4 drill bit to retap to 1/4"?
Link Posted: 6/24/2008 2:41:32 PM EDT
[#1]
If you have an easy out you could use it to remove the tap you would have to drill the tap with a bit made of carbide or something VERY strong other wise you will break the drill bit off inside the tap and make things even harder :(
Link Posted: 6/24/2008 3:37:27 PM EDT
[#2]

Quoted:
Its a #10 hole, so do I drill it out with a 1/4 drill bit to retap to 1/4"?


Well that won't work, the tap drill for a 1/4" thread is an "F" drill IIRC.  There are tap extractors, but I don't know how well they work.  Probably get them from MSC Industrial Supply, or McMaster-Carr.
Link Posted: 6/24/2008 4:16:45 PM EDT
[#3]
where is the tap broken off in?
rear trunnion?
if so, what i do on really pigheaded rivets, i just take a dremmel to the underside of it, and slice it open, it pops open usualy once the dremmel cuts through all of it, and then i can punch out the old rivet, and whatever drill bit and punches i have broken off in it.
just weld  the cut with a mig once your ready to reassemble, and you are good to go.
Link Posted: 6/24/2008 5:13:32 PM EDT
[#4]

Quoted:

Quoted:
Its a #10 hole, so do I drill it out with a 1/4 drill bit to retap to 1/4"?


Well that won't work, the tap drill for a 1/4" thread is an "F" drill IIRC.  There are tap extractors, but I don't know how well they work.  Probably get them from MSC Industrial Supply, or McMaster-Carr.


Yea, I know.  I just mentioned 1/4 because I didnt know off the top of my head. Thanks.

The tap is broken on a screw build in the front trunnion, so i cant get it from the other (barrel) side.
Link Posted: 6/24/2008 5:21:23 PM EDT
[#5]
The most efficient way is to ram EDM it, but you most likely don't have access to a Ram EDM.

Therefor, I would remove the barrel and than drive the broken tap thru into the trunnion and than drill and tap for the next size up and than re-install the barrel.
Link Posted: 6/25/2008 8:43:05 AM EDT
[#6]
Man Im not trying to be a naysayer, but I used to install commercial doors and hardware and had to tap all the holes for the door closers, handles, etc... in the steel doors.   And of the 3 taps that I broke off, I didnt get one of them out, I tried soaking with penetrating oil and everything.. cby the time the thing breaks it is already wound in there super super tight thus causing it to snap... I found out to always make sure you spray WD40 on the tap about every turn, also backing it out and flushing the shavings out with WD40...

I would do some serious research on the  topic and see what you can find... those things being made out of tool steel are real hard and might not drill well if at all for an easy out       good luck man, I  hope you get things resolved, you def have a can of worms there

I found these on google for yah


broken tap


Engineering Hobbyist
Link Posted: 6/25/2008 9:00:37 AM EDT
[#7]
Automotive parts stores have great bits for doing this that don't cost very much.  I think even hardware stores have them.  Typically they are square and are beveled.  I hope that helps, I find them to be rather easy to use and a life saver.
Link Posted: 6/25/2008 1:30:17 PM EDT
[#8]
As a Tool and Diemaker, I would guess that the tap bottomed out, or is packed with chips or the tap was bend ever so slightly to cause it to snap. They do make tap extractors, but I have found them to be useless at best.

Taps are made from tool steel, and if you desire to drill them out, you would need a mill and carbide drills or endmills.

There is something that may work, sometimes it does and sometimes it doesn't. Use a air compressor and blow as many of the chips out as possible, use a dental pick and work some chips loose and repeat with the air. Keep repeating until the chips are clear, that try a tap extractor.
Link Posted: 6/25/2008 4:13:56 PM EDT
[#9]
use a pair of hemostats/forceps or fine needle nose pliers. stick it into the flutes of the tap and "unscrew" it. That works about 80% of the time.

The remaining 20% involves swearing and throwing things.
Link Posted: 6/25/2008 5:47:01 PM EDT
[#10]
Taps are pretty brittle. I have had some success breaking them out with a hardened punch.
Link Posted: 7/8/2008 7:16:07 PM EDT
[#12]
Spend the money & have it done right. Let a local shop EDM it out. probally cost you about $75
Link Posted: 7/8/2008 10:35:18 PM EDT
[#13]
Drill it out with a cobalt bit :D
Link Posted: 7/9/2008 6:04:10 PM EDT
[#14]
Remove the barrel and knock it out.
Link Posted: 7/22/2008 9:54:52 AM EDT
[#15]
i just had this happen to me too.  i tried the tap extractors, e-z outs, etc with no luck.  ended up grinding it out with a succession of 5/32" stihl chainsaw sharpening bits.  it took 4 bits.  i stil don't know how i snapped it off.  i was cleaning out the hole after i'd already done the heavy cutting and -tink- it snapped.  there are only two kinds of builders, those who've snapped off a drill bit or tap, and those who will.  
Link Posted: 7/22/2008 11:11:24 AM EDT
[#16]
I joined the club on my 1st build.  Maybe that's why it took so long to build the 1st!
Page AK-47 » Build It Yourself
AK Sponsor: palmetto
Close Join Our Mail List to Stay Up To Date! Win a FREE Membership!

Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!

You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.


By signing up you agree to our User Agreement. *Must have a registered ARFCOM account to win.
Top Top