For sale: one MAC Tools 3/8" drive specialty wrench 9D7437 (9D may be a year marking leaving part #7437), new and unused.
Condition? Mint. Mystery? High.
The “Sabina O.” marking means it predates ~1980. Beyond that? Your guess is as good as mine. I’ve been through old MAC catalogs and can’t even find a cousin to this thing. It looks like a bezel wrench (maybe for a ’42 Packard dashboard, maybe for a submarine).
Back in 2014, I posted this in Garage Journal. The crowd had guesses galore, but no one cracked the code. So here’s the deal: I’ll give a 25% discount to anyone who can prove exactly what this tool was meant for. That’s right—help solve a decades-old MAC Tools mystery, and save some cash.
What’s certain:
It’s authentic, Made in USA.
It’s uncommon enough that seasoned collectors haven’t seen another.
It’s in excellent condition, no ID markings.
I’ll offer a 25% discount to anyone who can document its exact intended use.
Until then, it remains what it is: a well-made tool, and a mystery.
No owner ID markings.
Made in USA.
Pretty enough to hang on the wall, mysterious enough to keep your mechanic friends arguing all night.
Q&A:
Q: What’s the discount for knowing what this is?
A: 25% if you have convincing evidence. Thomas
Q: lol, I’ll tell you anyways, it’s a canister filter socket from the 60/70’s, I’ve only seen 1 other. I was a heavy mechanic back in late 80’s, head mechanic had one in his truck. The housing it fit was only on A few machines, but he kept it just in case.
A: Canister filter socket is believable. Is there a known specific application?
Q: Don’t remember the application, but head mechanic only worked heavy machinery. I do know it was a high pressure system, where the filter was encased and that was used to remove the end cap. Almost want to say Deutz.
A: Ok, thanks a million for sharing that. By heavy machinery do you mean like mining of construction machinery?
Q: Yes. He was a military mechanic from Korea,Vietnam etc. Probably shouldn’t sell it. To collectors that’s almost a holy grail.
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Q: Okay so I have no proof of this but from looking at the spline in the machining on the inside of this it was very expensive to produce back in the day makes me think that it only being a four digit number was a military contract and this probably put an auxiliary gear on a jet engine somewhere along the line.
A: Thank you for that. It does look expensive to make but, it seems like the broaching process they use for sockets could do it. It is also a very unusual part number. I haven't seen anything like it in MAC catalogs. If you find anything further, please continue to share. Thomas
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Q: This is a serrated oil filter socket wrench made by MAC Tools (from Sabina, Ohio).
Q:
A: That's very interesting. Exactly what I tried before I listed it. Chat GPT must have finally figured it out after all the people from eBay asking it. It probably got the spin-on oil filter idea from the Q&A section of the listing. I tried the same thing you did, and got pretty much the same answer, but when I Asked to proceed with pulling a catalog reference it fell flat.
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Q: It’s a 100 point socket duh…. Yes I actually counted 😂
A: Interesting! Thomas
Q: Unfortunately I don’t need one cause I already have more of those than I would ever use so someone else can get the discount !
A: You are very generous!
Q: I try to be😂 I do hope you find someone though that can find that tools true purpose!