Hex Nut Markings

Jimbrown · Dec 7, 2006

I have searched high and low to find the markings on a nut that I have.
i can identify the the meaning of the three slash marks. Grade c high carbon resitant to elements. But what the heck does the marking with the two triangles mean? Anyone know. see attached drawing.

DieselPower · Dec 7, 2006

You are correct about the grade mark. The other marking's are most likely the manufacturer's mark. Many nut/bolt manufacturers also mark all their hardware with a mark not unlike you find on gold and silver jewlery that has "hallmark's". I have a book around here somewhere that has alot of the manufacturers marks in it. I'll try to see if I can find it and look up the mark for you.

gordon21 · Dec 7, 2006

Here's a chart for land based fasteners. There are more markings for aviation hardware not on this generic chart.

Bolt Head Markings Chart by Zero Fasteners

DieselPower · Dec 7, 2006

Those are still ASTM/SAE marking's though and not manufacturers marking's.

gordon21 · Dec 7, 2006

Here are some more markings, but I still don't see ones similar to your picture. They must be a MFGR mark or something really obscure if they are not on one of the two charts I posted.

See page 2 of the Adobe file when the link opens.
http://www2.tech.purdue.edu/at/courses/at308/Technical_Links/Ac43-13-1B/CH7_3.pdf

DieselPower · Dec 7, 2006

There are thousands of head marking's. Here is a very small 162 page listing of some of the different manufacturers head marking's. This list only covers some of the ones you might run across. http://www.dot.state.il.us/materials/fasteneridentificationguide.pdf

The triangle is found on Vermont manufacturing bolts and nuts. They normally use a single triangle though. Could be thiers though.

Jimbrown · Dec 7, 2006

Those are BOLT markings and I can find all kinds of them in great detail. However none of the charts you show have NUT markings. Nut markings seem to be some great secret. I believe that the two triangles mean self locking but I can not find anything that verifies that. This site here is one of the better ones and has the slash marks but not the triangles.
American Fastener - ASTM, SAE, and ISO Grade Markings

The reasonI was asking was because they are on the lug nuts that came on my new horse trailer. But they seem to be the wrong size or they have some sort of self locking on them. They will not just screw on and off like a normal lug nut does. You have to use a wrench all they way on and off. It is either that or the factory put 17mm nuts on a 1/2 in lug. This is kinda what I suspect also. Because when I take a regular 1/2 X 20 lug I can just screw it on with my fingers.

jwnge · Dec 7, 2006

If I remember correctly,Those have a interrupted fit, a slight squeeze or miss fit to not let them fall off if they come loose, kind of like a lock nut but not as much so, just a safety factor. John

DieselPower · Dec 7, 2006

Jimbrown said:
Those are BOLT markings and I can find all kinds of them in great detail. However none of the charts you show have NUT markings. Nut markings seem to be some great secret. I believe that the two triangles mean self locking but I can not find anything that verifies that. This site here is one of the better ones and has the slash marks but not the triangles.
American Fastener - ASTM, SAE, and ISO Grade Markings

The reasonI was asking was because they are on the lug nuts that came on my new horse trailer. But they seem to be the wrong size or they have some sort of self locking on them. They will not just screw on and off like a normal lug nut does. You have to use a wrench all they way on and off. It is either that or the factory put 17mm nuts on a 1/2 in lug. This is kinda what I suspect also. Because when I take a regular 1/2 X 20 lug I can just screw it on with my fingers.

Did you actually look at the IL state PDF link? It has hundreds if not a thousand NUT marking's. They start on page 82 and continue to page 162.

You can also check the US Patent Office Fastener Insignias Register. http://www.uspto.gov/web/offices/tac/fqa/active.pdf

gordon21 · Dec 7, 2006

A new horse trailer?? I would be going back to the dealer ASAP and demanding an explanation. Neither he nor the mfgr will want to honor a claim for new hubs in 3 years when you claim it was screwed up from day one. Look at another trailer on his lot to see if the nuts are the same and try to take one off. Lug nuts are kinda important when doing 70MPH with a couple horses in the back.......

dqdave1 · Dec 7, 2006

Not sure.
One triangle is the ID for a Canadian manufacturer.....I just looked through my world list of headmarkings and didn't come across a double triangle.
It's not any known Grade marking that I'm aware of.
I also see 3 lines on the face...are they really as drawn or do they match the curve of the ID?

Jimbrown · Dec 8, 2006

They match the curve I just could not draw them that way.

Jimbrown · Dec 8, 2006

Sorry Diesel Power I was refering to Gordon21's site it was only a few pages long. Yours was extensive. I was impressed. I am sure from looking at the two references that you gave me that it is a manufatures mark. Probably some off shore place as everything else is made in some other country. The wheels are from Brazil, tires are who knows chinese. The axels are dexter and they just say 1/2 x 20 for the studs. I am just going to replace them all as I take wheels off for repairs. I already had two flats so it will not be long. Gordon21 well I would take it back to the dealer but this is Arizona high desert it is 13 miles of dirt road and than another 125 miles to the dealer. I am not going to haul it 250 miles just to have some guy say "thems the ones that come on them all." They very well may be designed to be interference fit. It is just a pain to have to wrench 8 of them all the way off and on.

Tom_Veatch · Dec 8, 2006

Jimbrown said:
... It is either that or the factory put 17mm nuts on a 1/2 in lug. This is kinda what I suspect also. Because when I take a regular 1/2 X 20 lug I can just screw it on with my fingers.

If the male threads are 1/2x20 the nuts aren't metric, and certainly not 17mm.

Most likely what you have is an 1/2 SL nut where the self locking feature is obtained by intentionally deforming the threads to obtain a slight interference fit.

Standard metric threads jump from 16 to 18mm and that size nut (.630 to .709 nom. dia) would fall off a 1/2" (.500) stud. The closest metric nut to that size would be a 12 mm (.472) which would be too small to fit. The next larger standard size, a coarse thread 14 mm (.551) with 2.00 mm pitch, might have a minor diameter small enough to engage the threads, but the pitch would be the equivalent of 12.7 tpi. So even if it were a 14 mm nut, and you did manage to wrench it on and off a 1/2x20 stud, either the stud or the nut would be damaged by the attempt.

Jimbrown · Dec 11, 2006

I guess you are correct. I called the factory they did not have clue what I was talking about so I guess they may indeed be interference fit. I am going to change them all anyway. last thing I want is to be on the side of the road in 100 degree heat twisting 8 of them all the way off and on with two horses stomping all over the place.

DieselPower · Dec 11, 2006

Sounds like someone needs a 1/2 inch cordless impact wrench for christmas.

deerhunterf350 · Dec 13, 2006

Jimbrown said:
I guess you are correct. I called the factory they did not have clue what I was talking about so I guess they may indeed be interference fit. I am going to change them all anyway. last thing I want is to be on the side of the road in 100 degree heat twisting 8 of them all the way off and on with two horses stomping all over the place.

Just a thought , change 6 Nuts out with Standard Threads, but keep 2 of the Interference fit nuts opposite each other as a Saftey Factor. Just in case in a MILLION years they work loose, you will still have 2 Nuts holding the wheel tight.

Doing that could keep those Two Horses from FLYING for a few seconds, and the tow vehicle ending up not telling were. If you do have a Flat, spin those 2 nuts off first before jacking the wheel up.

Just My .02

rebelmedic · Dec 19, 2006

I`ve came across those same type nuts before.The triangles indeed are signs of a type of locking or as some of ya`ll are calling them interference fit. They are a pain to get off but never have to worry about one working loose.