Should You Use a Tap Extension Holder Or a Standard Extension Tap?

Extension Holders

Extension holders are available in a variety of styles including a square socket with set screw, a two jaw chuck style, a socket for each tap square and others. Typically the lengths that are available range from 6” to 18”. Most extensions are available with hex drive shanks, square shanks or round shanks. Assembly with standard NC, NF or metric size taps is easily accomplished. The cost justification of using a tap extension holder compared to the use of a solid extension tap is dependent on the expected production or useful life of the extension holder.

Extension Taps

Solid extension taps come in a variety of lengths and styles. Regal Cutting Tools offers both hand tap and spiral point styles from #4 to 1 ½”and M3 to M20.  Small sizes start at 4”length and progress by diameter to 6”, 8”, 10” and 12”.  Pipe styles NPT/NPTF are available in the same extended lengths. Special sizes and threads are available to meet any requirement in our 24-hour shipment from blank program.

Here are some important factors when deciding between the two:
  • Thread depth
  • Flank finish
  • Class of fit
  • Straightness
  • Number of threaded holes
extension taps
Other areas to consider:

For maintenance and repair applications extension holders are practical, for critically threaded holes and production tapping extension taps will operate more efficiently. Any time there is an assembly of parts, a hand tap and extension holder, there will likely be concentricity issues. Extension taps are built to operate in alignment of a few thousandths.
Machining centers using tombstone-type fixtures as shown, are not a problem for our extension taps. Users can select large shank tools for shallow tapping or reduced shanks when the required thread depth is longer than the tap thread length. These extra length taps are ideal for reaching inconvenient surfaces, and are designed for production tapping. The available spiral point design eliminates chips packing in the flutes and troublesome tangles of stringy chips.
Still unsure about which product would be the best fit for your application? Contact Us.