Lump finds weird Snap On sockets

[Lump]

During my recent trip to KY to pick up my bargain-priced Baldor grinder, I stopped at a little roadside flea market. There were lots of tools, to my surprise, and quite a few Snap On and Mac tools. But no bargains, from my perspective. One gentleman had a couple of sets of Snap On sockets for sale, which I had not seen or used before. I'm sure I could search and find them in an old Snap On catalog, or online somewhere. But I always enjoy sharing my finds and adventures with my GJ pals, and I thought some of you would instantly know what these special Snap On socket sets are for. So here goes:

Note: no hex, inside or out:

Regular 3/8" drive:

I got a couple of shots of part numbers on the sockets:

Below: This last one has one part number character illegible. Is it a double stamp or error, or is that a character I should be able to read? Maybe an "E?" So, what are they, Oh S-O gurus?

Finally, he wanted $100 for this set, and $75 for another smaller set, but he didn't know what they were for. Good price? I left 'em there.

If you want to see the Garage Journal thread about that Baldor grinder I got for $21.50 on eBay, or more pix of the trip to go get it, here is a link:
http://www.garagejournal.com/forum/showthread.php?t=104175

 

[smallcarguy]

I think those are for hydraulic fittings.

 

[neonnblack]

Yes hydraulic, weather head fittings, used most in aviation. 70-95 vintage.

 

[crewchief888]

weatherhead sockets are one of those things you'll probably never need....

if you do need one, you really need one cuz thats all that'll work.

i have 2 or 3 of them, them lil bastids are expensive.

i installed several low pressure grease systems on some vibratory rollers a few years ago, having the weatherhead sockets were a life saver

 

[Lump]

Ahhh... I assumed it would be for something like that. And since I didn't recognize them, I was pretty confident I would never need them for myself. And to buy them for resale would be a BIG gamble. Who wants to have a $100 invested in a used, engraved socket set that you'll never need? And if you find out that it is obsolete, and so no one else wants it very badly, then you're stuck with it. And THAT is why over-cautious ol' Lump left it lying there on his table.

He was a really nice guy though, and I promised to email him when I found out what they were for.

 

[durallymax]

which weatherhead fittings are these supposed to work on?