Fan blade bolts

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I am working on the stuff that mounts to my engine and the current project is the fan.

I have the blade retaining bolts out and find that they are neither #10 or 1/4″ and I can’t find any #12 hex head bolts.

Are they in fact #12’s and if so, anyone know of a source?

Thanks in advance.

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McMaster-Carr has a few 12-24 hex screws. They are amazing!

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Gardner-Westcott Company

Northville MI

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Thanks Michael and Roger. I forgot all about G-W.

I cleaned up one bolt and it has 1035 stamped in it. Is that a steel grade, doubtful, a bolt/thread pattern, if so I can’t find it or something else.

This is fine thread, it isn’t 24,28 or 32 TPI. Leave it to the PA engineers to come up with some more item made from unobtanium.

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I don’t know a source, but mine are exactly #12-32 screws which is not listed in my machinists handbook as anything standard. That said, I had a 24 Studebaker once and it too used some really unusual fasteners in odd places which makes me wonder if they influenced Pierce at that point in history???

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Peter,

I have a wall chart that you screw the nuts/bolts into and I get NADA.

To Mark’s point, refer to my previous mention of PA engineers and unobtanium.

Word to the wise, don’t throw these bolts away.

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Bill,

Do you need all eight of them?

Bill

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The size 12-32 is indeed real. MSC carries both dies and taps in this size if you need to clean up the ones you have or make new ones from stock. Amazon advertises a go/nogo thread gauge for this size.

No, it is not a common size; #12 is an oddball size anyway, but the UNC/UNF standard thread counts are 24 and 28 per inch. The most common 32 thread count is a #10 screw.

Best of luck,

Herb Tull

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William and Herb,

William, yes I was trying to replace them all. Not missing any, just wanted new.

Herb, thanks for the info and the lead. I will let you know what I find.

Bill

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