Snap-on drive size question.

[username2]

I just liberated an old Snap-on 12pt impact socket from a thrift store, 1/2" drive, brought it home.

There's no way it fits any of my 1/2" stuff, but it fits a vintage Snap-on ratchet that I bought just fine. It's all just slightly smaller than modern.

so...did the definition of 1/2" change over time? expansion of the universe? 31/64" drive during the war era? Enquiring minds want to know.

 

[snapmom]

They made 5/8 dr. industrial sockets well into the 60s and probably later. they look like impacts. also made 9/32 dr. industrial about the same time period.

 

[Provincial]

A 12-point impact socket would be unusual. Impact on that small contact area would wear/distort quickly. Perhaps it is a power drive socket from an assembly plant.

Please post a photo of the socket drive end. Also measure the dimensions of the square recess.

 

[username2]

Probably not impact, looking at it more closely. Just really old bare metal.

The ratchet it fits fine into is marked 71-15 and my Hecho en China measuring thingie from HF claims that the drive end is .485"
(maybe just years of use).

The socket is marked Snap-on 1 1/8" S360 1/2 (1/2? what kind of witchcraft is that?) with some other code that looks like an Enron "E". ID (well, squareish ID) is around .494"ish. But there's no lip.

HF measuring thing sez .500 on drive of Snap-on GS936 I have lying around here.

I'm thinking false alarm. If I were to ever use it, maybe a file is in it's future.

 

[Private Lugnutz]

There's no way it fits any of my 1/2" stuff, but it fits a vintage Snap-on ratchet that I bought just fine.

Interchangeability from mid 20's to modern, same drive size, can be a little sketchy, not just Snap-on, but it has been observed before with them, too, due to manufacturing quality.

The socket is marked Snap-on 1 1/8" S360 1/2 (1/2? what kind of witchcraft is that?)

Take a breath, maybe a take a drink, and put your thinking cap on because this will get a little nutty to read!

The "1/2" marking is a suffix to the part number. In the mid-20's, when they were making the 5/8-inch drive (dubbed "Heavy Duty") that @snapmom alluded to, they were making 1/2-drive (dubbed "Master") at the same time. The problem is they didn't foresee the overlapping range (three largest openings in Master drive range being the same sizes as the three smallest openings in the HD drive range) issue coming when they - believe it or not - re-used the same part numbering scheme for the HD drive sockets. As a fix, they added a "1/2" suffix to the biggest 1/2-inch drive part numbers in their range to distinguish them from their 5/8-drive near-twins. At the time, it was only 300 1/2 (15/16"), 310 1/2 (31/32"), and 320 1/2 (1"), whereas 300, 310, and 320 (no suffixes!), were 15/16", 31/32" and 1" respectively in HD or 5/8-inch drive! (I warned you it was nutty!) But then, when they started making 1/2-inch drive sockets with larger openings, they kept the 1/2 suffix scheme going! Eventually they dropped the 5/8-drive, standardized on 3/4-drive, and gave them completely different prefixes. But those "1/2" suffixes prevailed.

By P/N, your socket should be a standard 1/2-drive socket with a 1-1/8" service opening.

The "E" could be a date code (1944).

 

[d42jeep]

Although you didn’t include a picture, here is a picture of some other wartime 1/2” drive Snap-on wartime sockets. The E marked are 1944 and the G marked are 1945. You may need to do a bit of filing on your socket. 12 point sockets are not recommended for impact duty.
-Don

 

[john.k]

.485 sound like 12mm to me ............some big companies bought special size tooling to discourage employee theft

 

[username2]

12 point sockets are not recommended for impact duty.

Not to worry, I'll save my 18 point sockets for all impact duty.

Pvt. Lugnutz...that is a complicated story. To their credit, these things appear pretty well documented. My current plan is to chase down the Snap-on truck and demand a warranty return on the socket, I'll save the $1.00 71-15 ratchet for security duty as a cosh. All is well.

 

[bwringer]

.485 sound like 12mm to me ............some big companies bought special size tooling to discourage employee theft

IIRC, some US military stuff did this as well. 9/32" drive is a well-known way to frustrate thieves, or at least make them take the larger risk of stealing a matching ratchet as well. No clue whether that's what's happening here (15/32" drive?), but it could be one of these deliberate oddballs that went home in someone's pocket or lunchbox long ago.

 

[isb cornbinder]

This is an uncommon drive size. I got it for a dollar. I have owned it for 30 years. I never bothered to ask about it. I have thought of butchering the square drive off and TIG welding a 3/8" square drive on.

 

[john.k]

Rockwell truck diffs use 12 point flanged bolts .......and I must have damaged dozens of ordinary sockets on these bolts using a 3/4 rattle gun and 1/2 -3/4 adapter ......Sidchrome sockets dont break ,but swell out .

 

[Private Lugnutz]

Pvt. Lugnutz...that is a complicated story.

Stranger than fiction!

When I first discovered the meaning of that little "1/2" marking - the same way as you, wondering what the heck it was, and what it signified, I figured it out by looking through catalogs, year by year. I imagine they might've gotten a few irate calls from mechanics complaining that their sockets don't fit or they keep reaching for the wrong ones.

But then they compounded the issue by sticking with the suffix scheme long after they needed to.

 

[Wrench97]

Although you didn’t include a picture, here is a picture of some other wartime 1/2” drive Snap-on wartime sockets. The E marked are 1944 and the G marked are 1945. You may need to do a bit of filing on your socket. 12 point sockets are not recommended for impact duty.
-Don

What do you use on 12pt nuts and bolts?

 

[Wrench97]

Probably not impact, looking at it more closely. Just really old bare metal.

The ratchet it fits fine into is marked 71-15 and my Hecho en China measuring thingie from HF claims that the drive end is .485"
(maybe just years of use).

The socket is marked Snap-on 1 1/8" S360 1/2 (1/2? what kind of witchcraft is that?) with some other code that looks like an Enron "E". ID (well, squareish ID) is around .494"ish. But there's no lip.

HF measuring thing sez .500 on drive of Snap-on GS936 I have lying around here.

I'm thinking false alarm. If I were to ever use it, maybe a file is in it's future.

Does the end appear to have been beaten with a hammer?
I've seen plenty of old sockets used as bushing installers, used a few myself had to touch up the opening with a file to get a ratchet to fit again........

 

[d42jeep]

What do you use on 12pt nuts and bolts?

Those weren’t too common during WW2, likely when your 1/2” drive socket was made.
-Don

 

[3baygarage]

If you want to see something, I have a handful of 1/2” drive Plomb torque adapter ratchets, all WWII era, all lightly used if at all, all acquired from different sellers, and a bunch of them no longer fit any drive tools. Not a one of them looks deformed, well used, etc…

 

[Provincial]

If you want to see something, I have a handful of 1/2” drive Plomb torque adapter ratchets, all WWII era, all lightly used if at all, all acquired from different sellers, and a bunch of them no longer fit any drive tools. Not a one of them looks deformed, well used, etc…

Yes! This will be an interesting rabbit hole to dive into.