ISO THREAD SIZE

[Paul O' Norton]

Hi all i wonder if anyone has any info on iso thread size as far as i know its 3/4 20tpi but is it unf or cycle form

 

[L.A.B.]

3/4" x 20 is UNEF (3/4" UNF is 16 tpi). Not Cycle (BSC) as 20 tpi was obsolete by this time. Cycle is also a 60-degree thread, it isn't a Whitworth (55-degree) thread.

 

[Paul O' Norton]

probably irrelevant but got this from a massey furguson tractor supplier, for their half nuts
DIN No: 439B
Grade: 8
Thread: 3/4" Inch UNF x 20tpi RH
Tensile Strength: 8.8

 

[Paul O' Norton]

Also found an nut for triumph triples NUT 3/4" x 20 TPI UNF (PLAIN) ZINC PLATED so ... part No 21.0585

 

[L.A.B.]

3/4" x 20 is UNEF so it can't be UNF as 3/4" UNF is 16 tpi.

TR knowledge base | Thread geometry - Unified Extra Fine (UNEF)

Thread geometry for Unified Extra Fine (UNEF) threads.

www.trfastenings.com

UNF Thread Size Chart | Unified National Fine Guide

Access the complete UNF Thread Size Chart. Find precise TPI, major diameter (inch/mm), and tap drill sizes for Unified National Fine threads (#0 to 1-1/2").

armpremfg.com

Andover Norton referring to a UNEF part as UNF doesn't entirely surprise me. The Massey Ferguson I can't comment on only that it has to be wrong.

21-0585 Nut 3/4" UNEF - Triumph - British Motorcycle Parts Ltd - Auckland NZ

Various uses including Wheel Spindle and Crankcase Nut on various Triumph models.

www.britishmotorcycleparts.co.nz

 

[L.A.B.]

Also found an nut for triumph triples NUT 3/4" x 20 TPI UNF (PLAIN) ZINC PLATED so ... part No 21.0585

Looks like AN has now removed UNF from the description.

Andover Norton - NUT 3/4

NUT 3/4

andover-norton.co.uk

"21.0585
NUT 3/4" x 20 TPI (PLAIN) ZINC PLATED"

 

[Paul O' Norton]

Thanks LAB for your responce and information much appreciated thanks