What is this set screw ?

[Gennady]

Hello there.
I have setscrews in my vintage Hendey lathe with following dimensions - thread matches the gauge with inscription "24 or 3/16/or 7/32" . Setscrew diameter 1/4" and length around 7/8. Has slotted head.

I looked trough various sources of fasteners but found nothing close to that. Wondering of someone can identify this setscrew.
Thnaks

 

[Susquatch]

Picture?

 

[Proxule]

Picture?

Looks to be a M12x1.5 pitch

 

[YotaBota]

I think the brits call them a "grub" screw.

 

[Stuart Samuel]

Looks to be a M12x1.5 pitch
View attachment 47385

Man, they sure make some tiny parks these days…

 

[Gennady]

Here we go.

 

[Susquatch]

Here we go.

Gotta love Smart Alec's like the guys above eh? They make me laugh and add the spice of life to the forum. I thought the giant screw was good, but that tiny park had me howling!

Nice Vernier. Yours might be older than mine!

Ya, that screw is an odd ball for sure. It might exist out there, but I would not have bothered looking. I'd a just made one and been done with it.

Easy to make it from a regular 1/4" bolt. Just need a lathe and a slitting saw. Might be able to find a small enough socket head to turn it down and use that instead.

 

[John Conroy]

1/4 - 24 is a screw size I have run into on pre war Harley Davidsons but is obsolete now. You can still buy a tap and die from KBC

 

[Susquatch]

1/4 - 24 is a screw size I have run into on pre war Harley Davidsons but is obsolete now. You can still buy tap a and die from KBC

I missed the 24 tpi.

No biggie though. Still easy to make your own with a lathe.

No lathe, no problem. Send me the old screw and I'll make one for you just for the fun of doing it.

PM me if you wanna do that.

 

[Gennady]

I missed the 24 tpi.

No biggie though. Still easy to make your own with a lathe.

No lathe, no problem. Send me the old screw and I'll make one for you just for the fun of doing it.

PM me if you wanna do that.

Thanks Susquatch. Appreciate your help. Is there another approach that might be viable - to get closest bigger modern setscrew with hex socket head, drill out thread from the hole and cut another thread instead. This way I will have "standard" screw and hex socket head

Story about vernier - it is from my father - he use to work on the plant that was built by the French company in former USSR and he has been given this vernier as a gift. AFAIK it is 60 years old.

 

[Proxule]

French company in former USSR and he has been given this vernier as a gift. AFAIK it is 60 years old.

Love it, can you elaborate?

 

[Susquatch]

Thanks Susquatch. Appreciate your help. Is there another approach that might be viable - to get closest bigger modern setscrew with hex socket head, drill out thread from the hole and cut another thread instead. This way I will have "standard" screw and hex socket head

Might be more than viable. Might be preferred.

More pictures so we can see the application in more detail.

Watch out for pictures of venusians preparing landing sites for the next expedition from mars.......

Story about vernier - it is from my father - he use to work on the plant that was built by the French company in former USSR and he has been given this vernier as a gift. AFAIK it is 60 years old.

Gotta love heirlooms with a story like that!

 

[Gennady]

I was born in USSR - Minsk, Belarus. My farther was working in the plant that was producing fridges. It was back then quite poorly designed fridge even for that times , even for USSR. At some point government purchased complete factory -turnkey solution - to manufacture modern fridges. It was huge undertaking but it was worth it - those fridges were hugely successful -modern, light , silent, efficient. When it was time for French engineers to hand it over and leave, they were given few small things as a gift to my father as he was closely working with them.

 

[trlvn]

Re 1/4-24, etc. AIUI, before the Unified Thread Standards, there was a set of National standards in the USA. Both were based on the same 60 degree thread form and many of the National standards became Unified standards with no change. A notable exception was for coarse 1/2 inch fasteners. NC was 1/2-12 while UNC became 1/2-13.

The National standards for 1/4 inch were:

Coarse: 1/4-20 (NC)
Fine: 1/4-28 (NF)
Extra fine: 1/4-32 (NEF)

But then there were a few 'extras'...

The NS series is a catch-all category for threads which have the American Standard form, but whose pitches are not in the National Coarse or National Fine series.

1/4-24 and 1/4-27 were 'common enough' to both get mentioned as "NS" standards (National Special?). See:

American screw thread gauges

American screw thread series, with diameters of clearance holes, size of tap drills, and size of nuts.

www.sizes.com

So, 1/4-24 is a "standard" if you squint at it just right!

In another thread, there was discussion of trying to find a #7-30 die. The page quoted above indicates that this size is no longer in use. (Since well before the 1930's?!?)

HTH

Craig
(I have a few really old taps in odd sizes and a bunch of lost hours of internet searches led me to this page.)

 

[kstrauss]

1/4 - 24 is a screw size I have run into on pre war Harley Davidsons but is obsolete now. You can still buy a tap and die from KBC

For another tidbit of useless info:
1/4-24 is the thread used in a US Army cryptographic unit (https://en.wikipedia.org/wiki/M-94)

Before you ask, I started but never finished a project to make a run of accurate M94 reproductions and spent many hours measuring several original devices.

 

[Gennady]

Here is application those setscrews are used for - it is cross-slide with gib tightening screws

 

[Susquatch]

Me? I'd get a 5/16 24 tap, some 5/16-24 nuts, some 5/16 socket set screws, and just tap it out bigger. I might not even bother with a drill. Try without first and drill if need be.
The nuts are lock nuts for longer set screws.

Lose the slotted head design.

Total no brainer for me.

 

[Stuart Samuel]

Just had to buy some new-old-stock screws off Ebay for work (Centre Block restoration stuff). 12-24 is still stocked by most hardware companies, but 12-24 brass oval head slot drive? Good luck.

 

[Susquatch]

@Gennady - I don't recall yours being brass, but no biggie if so. Get steel screws and add a brass nose insert. Might even be sold that way.

 

[Gennady]

I don't recall yours being brass,

No, mine is not brass. Screws are pushing steel flat gib with dimples on it, so no need for "soft" metal