Need a New Set of Threading Dies

[ChazzC]

One advantage of having adjustable dies is the ability to make threaded parts that will fit older, not quite standard, assemblies. An excellent example of this are even brand new Starrett items: I recently learned that the threaded end of a post was something like 0.15”-24 - 12-24 was too tight, but with an adjustable die you could make one to fit (apparently the original spec was based on a prototype and that’s how the machinist/toolmaker built it).

 

[OTmachine]

Using thread cutting dies on manufactured fasteners will cut out the root of the threads potentially causing stress risers and weakening the fastener.

J type (rolled threads), are for high stress applications, (aircraft, etc.). There are specifications for most cut threads requiring a root radius, (usually ground on the single point tool. Yes, it does and always has caused stress risers which in most applications are not critical.

 

[rogerl]

Thanks for all of the replies. The hex dies I have are not adjustable and they have worked fine. I will look at the ones on Amazon. I will also look to find some "vintage" ones as well. Need to make sure the vintage ones are not rusted.

Thanks Again
Roger L

 

[CJ5Dave]

Guy on this forum has some quality taps. May have dies too.

https://www.hobby-machinist.com/threads/sae-taps-from-2-56-to-1-2-20-summer-sale.106897/

 

[mmcmdl]

Depending on what you decide on , I have quite a few myself .

 

[mattthemuppet2]

I'd just buy decent adjustable ones as you need them. Everyone's use is different but I use one for cutting threads (as opposed to cleaning them up) a few times a year and there are a bunch of the ones in my set that I've never used. I'd be wary of buying used ones - in all the ones I've bought I reckon I've had about a 60% good rate. The others usually have broken teeth or are dull.