110. Removal of Broken Tap.-
Taps will sometimes break off, even when used with care.
There are two ways of satisfactorily removing the broken part of a tap from a hole:
(1)
by means of a tap extractor;
(2)
by using a chisel or punch.
A tap extractor having 4 "fingers" that slip along the flutes of the tap is shown in Fig. 92.
This tool is turned with a wrench, which must be used carefully to prevent damage to the long thin fingers of the extractor.
FIG. 92.
USE OF TAP EXTRACTOR.
Broken taps can often be removed by using a blunt cold chisel or a taper punch, as shown in Fig. 93.
103
FIG. 93.
REMOVING BROKEN TAP WITH PUNCH.
If done carefully, this will frequently start the tap.
The job can then be completed with a tap extractor as previously described.
Taps often shatter when they break; the broken pieces should be picked from the hole with a small prick punch or a magnetized scriber before any attempt is made to remove the tap.
Removing a broken tap by any method is often a long, tedious job which requires time, skill, and patience.
It is therefore wise to avoid breakage by being as careful as possible.
http://www.maritime.org/doc/tools/part2.htm
http://www.waltontools.com/products/remvtap.htm
http://www.newmantools.com/walton/extrtap.htm
saludos