Extension Taps Add Flexibility to Machining Centers

Setting up complex parts on machining centers can be challenging especially when multiple operations are required. The difficulty occurs when either the fixture or the part itself are designed in such a way that reaching the surface to machine with the spindle can’t be accomplished easily.

Extension Drills and Reamers

For years, there have been extension drills and reamers, even end mills with extended shanks or long flute lengths. These came about because of deep drilled and reamed holes and wide face and contouring cuts with end mills.  Drill presses, multi-station production machines, screw machines and manual milling machines were all methods employed to get these jobs done. Because of the proximity of the spindle to the work, there was little need for long taps. The most common application for extension taps by far has been tapping the hub in pulleys.


The desire for efficient production speed greatly accelerated the development of machining centers. With that evolution, came the advance in fixtures commonly known today as tombstones. The advantage of mounting multiple parts on one single fixture and programming to achieve all the necessary operations required. Deep hole drills, extended shank reamers and end mills were readily available, but only a limited range of sizes and styles, mostly designed for maintenance, have been available.

New Tap and Shank Sizes

Regal now offers sizes from a #4 to 1 ½” both in production hand taps and spiral point styles. Standard shanks and small shanks are available when thread lengths are needed that are longer than the taps thread length.  Metric sizes as well as taper pipe from 1/16” to 1” are stocked.

Now programming a machining center with complex tapping requirements can be done to enhance productivity.