Snap-on TF 1127 Thread Restorer Question

[Jokerman]

Recently acquired a TF-1127 thread restorer. Included on it are a 15 and 26 threads per inch number. Not sure what these two numbers would have been used for? Any ideas. Contacted Snap-on and they couldn't provide an answer.

Hoping for some insight. Jim

 

[Robert Haas]

I have both SAE and metric, you sure you are not misreading the stamp?

 

[rlitman]

I see those numbers on a file on eBay:

 

[St-rider]

Those are threads per inch. Since it is not round or designed to cut a specific type or class of thread it simply states how many sharp edges per inch of length are there. Just for cleaning bolts and externally threaded rods.

 

[Jokerman]

The numbers 15 and 26 are on both the tool and the packaging. They do not appear to be standard UNC or UNF thread sizes. So curious as to what they are used for?

 

[rlitman]

The numbers 15 and 26 are on both the tool and the packaging. They do not appear to be standard UNC or UNF thread sizes. So curious as to what they are used for?

UNC and UNF are by no means the end-all of threads. There's of course UNS, but there are many others. Google tells me that British Standard Brass uses 26 TPI for all sizes. British Standard Cycle uses 26 TPI for many sizes, and has a 60 degree angle.

But otherwise, yeah, I've got no clue what they were meant for.

 

[Stuart in MN]

Maybe they were used for thread counts that are obsolete today. I didn't find anything right away for 15 tpi, but did find a reference to 26 tpi used on some old British motorcycle bolts.