Here is my favorite Question about the Type 2 Longworth Chuck by Ron Brown's Best- 

) Question What is the difference between a Type 1 Longworth and a Type 2 Longworth Chuck?

Answer) Type 1 has been on the market for almost 10 years and has gained worldwide acceptance. It uses the traditional configuration, but is equipped with a steel mounting disk on the back designed to be held in the jaws of a 4 Jaw woodworking scroll chuck. Both disks in a Type 1 Longworth Chuck are .25” phenolic with a 1/8” disk of UHMW plastic (Ultra High Molecular Weight) sandwiched in between to reduce friction. This isn’t needed with HDPE plastic.

Answer) The Type 2 Longworth Chuck is different in 3 major areas:

i) The disks are ½” HDPE (high density polyethylene) and there is no UHMU layer needed.

ii) The Type 2 is equipped with a threaded faceplate and threads directly onto the lathe spindle.

iii) An OPTIONAL accessory is a set of Doughnut rings for use with the Type 2 Longworth Style Chuck only. The Type 2 chuck may be used in the traditional Longworth scrolling mode or as a traditional Doughnut Chuck with doughnut rings.