Figure 4-106. Thread Chasers
Figure 4-107. Straight Screw Extractor
Figure 4-108. Spiral Screw Extractors
Figure 4-109. Tap Extractor
Screws and taps can be removed with the
spiral screw extractor.
Spiral extractor. To remove a broken screw or
tap with a spiral extractor, proceed as follows:
Always wear eye protection when drilling.
Failure to comply may result in serious
injury to personnel.
Center punch and drill a hole of the proper
size in the screw or tap. Use a drill size guide if
available. If one is not available, drill the hole slightly
smaller than the diameter of the extractor.
Some extractors have the required drill size
stamped on them.
Insert the extractor into the drilled hole.
Place a tap wrench or an open-end
wrench on the extractor.
Remove the broken screw by turning the
Tap extractor. If a tap has broken off at or
slightly below the surface of the work, proceed as
Apply a liberal amount of penetrating oil,
Federal Specification VV-P-216, to the broken tap.
Place the tap extractor over the broken
tap and lower the upper collar to insert the four sliding
prongs down into the four flutes of the tap, as shown in