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Patriot Chuck Thread Adaptors


Robert Sorby Threaded Inserts and Excerts

Patriot chuck thread adaptors allow the Patriot chuck to be fitted to any woodturning lathe.  As a neat way to reduce the cost, the standard Robert Sorby chuck has a single size thread cut in to the body, you then use a threaded adapter.

The Patriot chuck thread adaptors come in two types:

  • Internal thread type, screws onto the spindle. It is the smaller of the two types.
  • Excert or thread reducer, where the spindle thread is larger than the thread in the chuck body.  These are a much larger unit and will add length to the lathe spindle.

The advantage to this system is two fold. If you have more than one lathe, you can buy the thread adaptor that fits each spindle and just swap them allowing you to use the same chuck. Secondly, if you replace your existing lathe you don’t have to upgrade your chuck, just change the adaptor.

The Patriot chuck adaptors have a hexagonal flange so they are easily tightened into place.

Available in both imperial and metric thread sizes, there’s even a blank so the thread can be cut to suit the spindle.


These screw into chucks with an internal thread of M38 x 3mm.

Patriot Chuck Thread Adaptors Size Chart

Each Robert Sorby Patriot Chuck Thread Adaptors has a letter stamped on it which relates to its size. If you know the size you need you can simply select it from the menu above but if you only know the letter, here is a list of the sizes against the letter.

  • A = 3/4 X 16UNF
  • B = M20 x 2
  • C = M20 x 1.5
  • D = 7/8″ x 16
  • E = 1″ x 10BSF
  • F = M25 x 2
  • G = 7/8″ 12LH
  • H = 1″ x 10BSF LH
  • J = 1″ x 8UNC
  • K = 5/8″ Bore
  • L = M18 x 2.5
  • O = 1″ x 12
  • P = 1.1/8″ x 12
  • R = 3/4″ x 10BSW
  • S = M30 x 2.5
  • T = 1.1/4″ x 8tpi
  • U = 24 x 3
  • Y = M30 x 1.5
Part Number:

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