Threading tool tpi

[William Rogers]

I have been thinking about threading tool. I watched Mike Peace’s video and that provided good info. His recommendation was 16 tpi. I know you need a good hard wood for threading. I thought I read at some point that the coarser 10 tpi threads worked better. What is the recommended tpi? Also the Sorby has a sizing tool. Is that tool worth the extra cost”? A threading jig is too many $$$ for me.

 

[hockenbery]

Like most things in Woodturning it is a trade off

finer threads are much easier to learn chasing with

coarse threads easier to use
10 tpi a lot fewer turns to open than 16tpi than

 

[robo hippy]

I think the biggest difference is in how much you have to adjust the shoulder to get the grain to line up. With 16 tpi, you have to adjust at most 1/16 of an inch. Not sure how 10 tpi translates into depth, but you may have to go farther. The mechanical threaders can cut threads in almost any wood. Far more limited with hand chasing. Best video I ever saw was Alan Batty, and it us up on You Tube.

robo hippy

 

[GRJensen]

You asked about the Sorby sizing tool ... I have one, and use it whether I am hand-chasing or using my jig. It came as part of my Sorby 16-tpi thread-chasing kit (male & female chasers, sizing gauge, and too support rest), so I don't know how much it costs, but I definitely find it worthwhile.

 

[Richard Aldrich]

Gerald. What is the maximum the sorby jig can measure? My jig will go up to 5 inches. I find it difficulty to measure with calipers anything over 3 inches. The standard are 6 inch. Just about all have 1-1/2 jaws to measure which gives a 3inch tennon. Thanks

 

[GRJensen]

Gerald. What is the maximum the sorby jig can measure? My jig will go up to 5 inches. I find it difficulty to measure with calipers anything over 3 inches. The standard are 6 inch. Just about all have 1-1/2 jaws to measure which gives a 3inch tennon. Thanks

The Sorby caliper max diameter is about 2.900 inches for the female and 3.000 inches for the male. My jig (the Boffin 53 from the U.K.) will only do a sphere about 2.500" in diameter. If I need to go larger than that, I hand chase and use an iGaging digital caliper ... make the male blankk about .080 larger in diameter than the female threads.

 

[Richard Aldrich]

Thank you so much!!!

 

[Don Wattenhofer]

The problem with wood is that it changes dimension with changes in humidity so with the 10 TPI (0.10" lead per thread) the threads can be sized loose enough to accommodate the seasonal changes.