3/16" 28 TPI screw, why so hard to find?

[nickel-city-fab]

FWIW, I just mail-ordered a 7/16-28 tap on Tues. for a (damned) deWalt grease gun hose... trying to do the vendor lock-in thing with unusual threads on one end of the hose. Ordered on Monday, arrived yesterday, total about $14. I'm OK with import carbon-steel taps for single use or low use oddball jobs, it is handy to have a good collection of those and eBay is much obliging for that kind of thing. Seriously it is amazing what you can find there.

[Bob Engelhardt]

I like this company for some hard to find stuff. There is a minimum purchase though. $25.00 now I think. 10-28 die is $11.50. Tap $9.50.

Hard to find? I think that they have the 1/4" taps covered: 15 pitches from 1/4-16 to 1/4-80

[Rich Carlstedt]

.................What is unknown is the logic behind the formula itself (-:

I did a lot of research on that question years ago and never found the answer - except
Early screws used wire --and wire was drawn through dies that had numbers , just like sheet metal , they used the term "gauge"
So it may have something to do with that ?

Never had the chance to ask Mel..... He ran the only "Nut" ( and bolt ) Museum in the USA
It was Mel's past time and he knew a great deal of info. He was in California and his museum's name was... da da da ...Mels Nut House ,, That's what he called it
Seriously it was called Mels Fastener Museum and a Forrest fire destroyed it in 2003 and Mel passed away a few years later .
I talked to him in 2000 and was researching screw/nut fabrication in the 1800's . He was an encyclopedia of thread info.
Things he told me I still remember like
Maudsley invented the first hex nut milling machine in 1829 ( Think railroad "Rain Tree Trials and "Rocket" also 1829) and the first " commercial nuts" were sold
by a tooling supplier ( catalog) 1854 in new England- I think Boston ( earliest he could find) ( 25 years later ! )
Did you know that the Buggy and Wagon industry was the creator of bolt standards ? Lots of buggy makers demanding hardware uniformity !
Great guy , too bad we lost that history.
Rich

Forgot the URL if you are interested
https://www.globalfastenernews.com/o...ener-news-usa/