Generally, finer pitch inserts are proportionately larger in the free state than coarse pitch inserts and therfore have to be "pre-wound" to a smaller diameter for installation.
Large coarse pitch inserts (and 2-56, 3-48, and M2.2 inserts) need only a threaded mandrel tool for installation.
HeliCoil® Hand Installation Tools:
TYPE I:Threaded Mandrel
Sizes 2-56 and 3-48
TYPE II: Prewinder
#4 through 1/2" UNC
#3 through 1/2" UNF
TYPE III: Threaded Mandrel
TYPE IV: Non-Captive Prewinder
9/16" through 11/2" UNF
9/16" through 11/2" UNC
STANLEY Engineered Fastening | Fasteners & Fastening Systems
For more than 40 years, STANLEY Engineered Fastening has been revolutionising fastening and assembly technologies for a variety of industries. STANLEY Engineered Fastening, a Stanley Black & Decker Inc. ...