Figure 13-21.--Removing a broken tap with a tap extractor.
Figure 13-22.--Using a plug weld to remove a broken tap.
If the tap has broken off at or slightly below the
tapping until you have cut away the shell and restored
surface of the work, you may be able to remove it with
the original threads.
the tap extractor shown in figure 13-21. Again, apply a
In cases where it is not necessary to replace the
liberal amount of penetrating oil to the broken tap. Place
capscrew or bolt with one of the same size, use a drill
the tap extractor over the broken tap and lower the upper
larger than the broken bolt to drill out the old bolt, as
collar to insert the four sliding prongs down into the four
shown in figure 13-19, view A. Tap the hole first, and
flutes of the tap. Then slide the bottom collar down to
then finish it with a bottoming tap as shown in view B.
the surface of the work so it will hold the prongs tightly
against the body of the extractor. Tighten the tap wrench
Replace the original capscrew or stud with a larger size.
on the square shank of the extractor and carefully work
Never do this without the concurrence of your QA
the extractor back and forth to loosen the tap. You may
office.
need to remove the extractor and strike a few sharp
blows with a small hammer and pin punch to jar the tap
REMOVING A BROKEN
loose. Then reinsert the tap remover and carefully try to
TAP FROM A HOLE
back the tap out of the hole.
Each size of tap requires its own size of tap
To remove a broken tap that protrudes from a hole,
extractor. They come in the following sizes: 1/4, 5/16,
generously apply penetrating oil to the tap, working it
3/8, 7/16, 1/2, 9/16, 5/8, 3/4, 7/8 and 1 inch.
down through the four flutes into the hole. Then grasp
the tap across the flats with locking pliers. Figure 13-20
When a tap extractor will not remove a broken tap,
shows this operation. Carefully ease the tap out of the
you may be able to do it with the plug weld method
shown in figure 13-22. Place a hex nut over the tap and
hole, adding penetrating oil as necessary.
13-17