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Broke tap

coachmbcoachmb Member Posts: 153 ✭✭✭
edited February 2009 in Ask the Experts
I broke a tap in a mauser action for scope base hole. Anyone have any ideals how to removing borken tape?
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Comments

  • brier-49brier-49 Member Posts: 7,106 ✭✭✭✭
    edited November -1
    Hardware stores carry tap removers, a fingered tool to turn the broken part out with.
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  • nononsensenononsense Member Posts: 10,928 ✭✭✭✭
    edited November -1
    coachmb,

    Print this out and nail it to your work room wall:

    http://www.metalartspress.com/PDFs/Removing_Frozen_or_Broken_Taps_and_Fasteners.pdf

    Processes not covered:

    Use a hardened punch to tap the flutes of the tap to back it out of the hole.

    Using a hardened punch, crack and chip the tap into pieces that can be removed from the hole.

    Drill the tap out and then pick out the thread.

    Take it to a shop that has the EDM machine to burn out the tap.

    Best.
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  • WCIWCI Member Posts: 1,974 ✭✭✭✭✭
    edited November -1
    Try gently getting a small screw driver flat head in there and see if you have enough to back it out. I have done this before both with success and failure. Just know when to quit. meaning when nothing happens try something different not harder.
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  • cbxjeffcbxjeff Member Posts: 17,647 ✭✭✭✭
    edited November -1
    I have used the punch approach with success. The problem you will have with this is that you probably have a very shallow hole. With just a few threads of engagement the punch will just push the tap to the side and not turn it. Try the tap removal tool. I have used those with success also. Be sure you fill the hole with Tapmatic or other tap lube. Don't force anything. Try both directions and if you can just get a few degrees of movement you are on your way home. Change direction of twist every time you get any movement. If you have to go the EDM route better go to the bank first unless you have a good pal with a shop. I could get it done for you but the cost of back & forth FFL transfers would cost too much since you are in NV.
    It's too late for me, save yourself.
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  • GunMonkeyGunMonkey Member Posts: 17 ✭✭
    edited November -1
    I've used a Jewelers sized drill bit to bore into the broken tap. Then gently tap in a very small Allen key, just enough to bite. Loosen away.
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  • peabopeabo Member Posts: 3,098
    edited November -1
    Put a left handed drill bit of appropriate size in a reversible drill and run it in reverse (left or counterclockwise). When the drill bit catches on the hard tap, sometimes it will screw it out.

    Now always, but sometimes works.


    Thanks---Peabo
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  • ern98ern98 Member Posts: 1,725 ✭✭✭✭✭
    edited November -1
    From those of us who have been there we feel for your problem. Broken taps are usually an individual experience into themselves. Each is a little different, with smaller taps being more difficult. As you say you were drilling a Mauser scope base hole, I assume you are using a 6-48 tap? Was the hole being tapped drilled thru? If it is thru use lots of thin lube and go after it with an air chuck. What you want to do is get all debris out from about the broken bit of tap and to get the lube in. After that you just have to figure out how to tease it into loosening up. Once you get it to move a little then you can get it to move more and more, until it's finally out. Those of us who tap such thing regularly find that the correct size drill, new taps and thru holes keep these problems to a minimum. Good luck......
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  • I.ShuteI.Shute Member Posts: 647 ✭
    edited November -1
    First you should try peabo's method. Left-hand drills aren't found in most stores but MSC Industrial Supply has them in the size you want. Get a #33 if the tap is a 6-48. Use a speed control drill and go as slow as you can and use a lube like thin cutting oil or?

    If I had it here I would get a 3/8" drive air impact wrench, reduce down to a 1/4" driver and connect to a 30 to 40 lb. air supply. Get a 1/4" hex short screw driver bit , 1/8th in. wide, grind down to .113 wide and shape the bottom to catch on the uneven top of the tap. Sharpen the bit to bite when turning to the left. Throttle the wrench down to 2 or 3 impacts per second and check the power of the wrench with your hand, make sure it's very light. Go as slow as you can.

    Or you can use a hammer type impact tool and do the same thing and tap with a light hammer - very lightly.

    They make a set of 1/4 in. hex left hand bits like this, but I can't find them this small. Whatever you do, work very lightly and when or if it moves keep working with it.
    Good luck!
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  • BufflerBuffler Member Posts: 821 ✭✭✭✭
    edited November -1
    Get some dental burrs or drill bits.They are very hard and will
    cut a screwdriver slot in the tap.We used kroil oil,everything
    worked great. Just go easy...don't rush,take your time.
    BE SAFE!! Buffler
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  • XXCrossXXCross Member Posts: 1,379 ✭✭✭
    edited November -1
    If you have a milling machine:

    If the tap drill was for a 6-48, you might try using an
    1/8 in carbide end mill....run it very slow and apply
    just enough pressure to keep it cutting.
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