7/8"-14 threads --looking for a fine thread

[Wally]

The standard thread for reloading dies are 7/8"-14 threads; which I believe are coarse thread. Can anyone tell me where I can obtain locking 7/8" rings that are fine thread?---I need them for two shafts used on a telescope mount.

Thank you!

[Winger Ed.]

I'd check out McMaster-Carr.

It's one of those places that if they don't have it---- you don't need it.

[country gent]

Wally. 7/8 9 is coarse or national coarse 7/8 14 is fine or national fine. Most optics use National Extra fine threads or a special. The easiest way to tell is with a thread pitch gauge to check the pitch. A 6" ruler will show 8 tpi, 16, tpi, 32 tpi, and 64 tpi. Even more so a lot of optics may be metric sizes and threads.

If it is 7/8 14 you might try a dies lock ring in them to see. If so they can be purchased from most reloading shops.

[Scrounge]

The standard thread for reloading dies are 7/8"-14 threads; which I believe are coarse thread. Can anyone tell me where I can obtain locking 7/8" rings that are fine thread?---I need them for two shafts used on a telescope mount.

Thank you!

7/8-14 is the fine thread. The 7/8" bolts I found at the Lumber II, my closest farm/lumber/feed store are 7/8-9, and that shows as NC on my tap and die chart. By comparison, 1/2-13 and 1/2-20 are the coarse and fine half inch bolts. I bought a foot or so of 7/8-14 from Grainger, as they are local to me. McMaster-Carr carries it too.

Found Country Gent already covered that, but there is a 7/8-20 NEF (national extra fine) thread, as well. That might be what you need.

https://www.sizes.com/tools/thread_ncnf.htm

Bill

[garandsrus]

McMaster-Carr has some but they are over $20 each. Pretty crazy!

[Wally]

Wally. 7/8 9 is coarse or national coarse 7/8 14 is fine or national fine. Most optics use National Extra fine threads or a special. The easiest way to tell is with a thread pitch gauge to check the pitch. A 6" ruler will show 8 tpi, 16, tpi, 32 tpi, and 64 tpi. Even more so a lot of optics may be metric sizes and threads.

If it is 7/8 14 you might try a dies lock ring in them to see. If so they can be purchased from most reloading shops.

Thank you----I measured the threaded shaft---it is 20 TPI...not 18. Advanced Auto parts lists a nut that is 7/8" x 20.

[Wally]

7/8-14 is the fine thread. The 7/8" bolts I found at the Lumber II, my closest farm/lumber/feed store are 7/8-9, and that shows as NC on my tap and die chart. By comparison, 1/2-13 and 1/2-20 are the coarse and fine half inch bolts. I bought a foot or so of 7/8-14 from Grainger, as they are local to me. McMaster-Carr carries it too.

Found Country Gent already covered that, but there is a 7/8-20 NEF (national extra fine) thread, as well. That might be what you need.

https://www.sizes.com/tools/thread_ncnf.htm

Bill

Thank you Bill---you are correct---it is 20 TPI not 18!

[DougGuy]

Thank you----I measured the threaded shaft---it is 20 TPI...not 18. Advanced Auto parts lists a nut that is 7/8" x 20.

Buy one nut, split it in half with a thin cutting wheel voila! There's two rings.

[Scrounge]

Thank you Bill---you are correct---it is 20 TPI not 18!

You're welcome. In case you're interested, Amazon has a set of 7/8-20 tap and die in HSS for $29, free shipping with delivery between Jan 31st & Feb 18th. And a guy I was talking to over at homemadetools.net just bought a set for some parts he's made for a hydraulic system. I asked him what he paid for his tap and die, though he does this stuff professionally so he probably didn't by Chinese import tooling. ;)

Bill

[Wally]

This is from Advance Auto

Yukon Gear Ppinion Nut 7/8-20 Thread, 1 1/8 Socket
Price
$8.99
1 YR REPLACEMENT IF DEFECTIVE
Part # 33146

[Dutchman]

7/8-20 thread is used on Criterian boring heads for milling machines as the mounting thread for the mandrels. Without looking in the machinery handbook its probably a standard extra fine thread series.

Its a common thread in machine tools.

https://duckduckgo.com/?q=7%2F8-20+nut&t=ffab&iax=images&ia=images

[Scrounge]

This is from Advance Auto

Yukon Gear Ppinion Nut 7/8-20 Thread, 1 1/8 Socket
Price
$8.99
1 YR REPLACEMENT IF DEFECTIVE
Part # 33146

Looked at Grainger, and they want about $36, but it's an 18-8 Stainless steel. https://www.grainger.com/search?searchQuery=7%2F8-20+nut&searchBar=true It's a thin low-profile nut. The part you found isn't available on the advance auto website, have to go to the store. Amazon has what looks like the same nut for $9.99, and free shipping, with 18 supposedly in stock. https://www.amazon.com/dp/B00EHN2OZA/ref=sr_aod_dp_ttl


Bill

[BP Dave]

Sometimes you find that stuff on the 'bay--but you need to know for sure what thread you're looking for.

[Tar Heel]

As I am reading all of this nut seeking, a jingle popped into my head. God I am getting old.

[Wally]

That can drive you nuts....

[MostlyLeverGuns]

Victor Machinery - victornet.com has a large selection of taps and dies along with some bolts and nuts in NEF and many other thread sizes found on firearms and other equipment

[country gent]

One of the handiest little hand outs is a decimal equivalents chart. Just a little plastic card about 3 x 5 with the decimal equivalents tap drill sizes metric, pipe taps. Most are 2 sided with one side inch and the other metric. These were made in wall size and pocket sized. They are a freebie normally given out at tool shows or salesman in the plant. An e-mail to Starret or Clevland twist drill (among others) will get you them also. The older ones are really nice and made from metal. A lot of times they save digging out the hand book or figuring the tap drill size.

We would take the pocket size and bolt them between 2 1/8" pieces of lexan, easier to clean as as they got brittle they didnt break up.

But one of these give most thread sizes tap drill sizes and decimal equivalents all in one handy place.

[Scrounge]

That gentleman I was talking to about 7/8" bolts and nuts also mentioned that he has a 7/8-24 tap and die. He did say he buys a bunch of this stuff on ebay. So I guess he's not as adverse to import tooling as I had assumed.

Bill

[fixit]

This corresponds with a deep dive I did a few years ago looking for a7/8 20 screw for muzzleloading purposes a few years ago..... I was absolutely unsuccessful. Found the nuts, but no screws!

[MaLar]

I bought some 7/8" X 14 in a harder grade and some nuts from Granger.