Proto 1/2 drive set

[bixxjs]

Hi Yall
Recent Ebay purchase, two strange sizes, 25/32 and 19/32.The latter seems to have had a tough life.
What year was this from?
I've got a Britool 1/2 drive set from the 1970s but it omits these sizes.

 

[Farmer J.]

Those are American sizes. Post no. 5 in the 'stickie' should help..
Some of the Britool stuff that I have includes those 2 sizes, they're not uncommon on British made stuff after WW2 like the 'TW Superslim' spanners.

 

[bmwrd0]

With the registered trademark but having the flying lady on the logo, mid to late sixties vintage is my best guess.

Nice find!

 

[Dave455]

Farmer J has it right!

The old American sizes (National Coarse/National Fine to the natives, ANC/ANF to us) used a lot of /32 sizes, especially on some of the less usual nut styles. Machinery’s handbook lists some. These are ‘SAE’ sizes. There was also another standard called USS (United States Standard), but those seem to be rare!

When everyone switched to ‘Unified’ threads in the ‘50’s, a lot of these vanished, but as the regular sizes mostly stayed the same, few in the U.S. even noticed!

The only size you commonly find now is 11/32, as that’s a standard nut size for (I think) a No.8 screw. In the U.K. you will only ever find those in the aerospace world, as the U.K. didn’t generally adopt the ‘numbered’ series , retaining BA till metrication (and even longer in some industries).

 

[lardy1]

In the mid 60's I had a bicycle with an odd sized 19/32 bolt head on it. Dad had some old open end wrench with that size.

I bought a used set of 3/8 drive SK 12 point sockets that has an 11/32 socket. SK website only lists 11/32 in 6 point so the set must be older than I thought. My wife has a wrench storage rack for her Craftsman combination wrenches with a slot labeled and dedicated to 11/32. I told her that slot would forever be void of the proper occupant. A couple weeks later I found an 11/32 Craftsman combination wrench at a flea market.

My mid 70's (I think) Wright 3/4 drive set doesn't include any 32's sizes.

 

[Provincial]

19/32=15mm almost exactly. Must have been an early Metric adopter bicycle.

I worked on airplanes starting in the early 1970's, and all the #8 hex fasteners are 11/32. I had to order that size combination wrench from Sears separately, as it wasn't in the regular set. I believe that 11/32 was included in the standard 1/4 drive socket sets.

 

[Farmer J.]

I checked my pld Britool hex drive set just to be sure, and the 19/32" is also the most mangled socket in my set. It's quite close to 5/16 BSW , 3/8 BSF as well as 15mm so quite likely used for those as well.