Old metal V new metal and bolts

fastfarmall · May 11, 2021

Old metal seem to rust down so far and them quit, anybody explain that to me,i am sure it wasn't cor ten steel back then,and another thing old bolts, a 1/2 inch used a round head and had a square nut, but need a 13/16 wrench, when did that change to a 3/4 inch wrench ?

Janicholson · May 11, 2021

There were steels made with more art than high science metallurgy before WW2. Some of them rust with near zero flaking or delamination of the rust from the core metal. Rust is relatively waterproof, and impermeable to air as well. Thus it can preform like Cor ten. The flexing of steel will flake rust off, or form cracks because it has near zero flexure. More modern steel has more pure constituents and may just rust in a far more flakey way. Jim

Loosehandle · May 11, 2021

I think you can still get the larger nuts in hex, like a 5/8 nut would be 1 1/16. My dad used to call them heavy pattern nuts.

Russ from MN · May 11, 2021

they're still available, but maybe not in the sizes your seeing, the bigger nuts were called heavy hex, but McMaster-Carr calls them extra-wide hex nuts. The ones I'm familiar with the 1/2 was a 7/8 wrench, 5/8 was 1-1/16, and 3/4 was 1-1/4. Some structural steel bolts are oversize, with bigger head size too, and the ones we used said A-325 on the head.

Tramway Guy · May 11, 2021

A-325 are Structural bolts. Meant for buildings, and bridges and the like. They are nearly equivalent to Grade 5, but with less thread and always heavy hex on heads and nuts. They are also available in a Hot-dip Galvanized version, which can only be used once.

showcrop · May 12, 2021

I sure wish that old metal would quit after rusting a little way. Once you have rust it will pull moisture out of the air and keep right on oxidizing the steel that you think that you are keeping dry. You may have seen plate rust that is 1/4 inch thick.

BarnyardEngineering · May 12, 2021

It's been at least 40 years, and probably more than 50, since a 1/2" bolt had a 13/16 hex head. I'm 46 and a 1/2" has had a 3/4" hex head since I've been around. I knew wrench sizes before I could count to 10.

Can't blame that one on 21st century corporate greed, or China.

Jim.ME · May 12, 2021

(quoted from post at 07:10:47 05/12/21) It's been at least 40 years, and probably more than 50, since a 1/2" bolt had a 13/16 hex head. I'm 46 and a 1/2" has had a 3/4" hex head since I've been around. I knew wrench sizes before I could count to 10.

Can't blame that one on 21st century corporate greed, or China.

Depends on the 1/2" bolt and use, even now not all have 3/4" heads. 13/16" is old, but current 1/2" heavy hex bolts have 7/8 hex heads.

bc · May 12, 2021

Don't know. I took a 85 year old windmill down last year. No rust and the galvanized bolts had square nuts. Once the nuts were broke loose, they all easily screwed with two fingers.

fastfarmall · May 12, 2021

Thats what i am talking about, and most times its not even galvanized, you break it loose, and the rest it is easy!

SVcummins · May 14, 2021

John Deere bolts for chisel plow point and sweeps are 1/2 inch with 7/8 hex nuts

Old metal V new metal and bolts

fastfarmall

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Janicholson

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Loosehandle

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Russ from MN

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Tramway Guy

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showcrop

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BarnyardEngineering

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Jim.ME

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bc

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fastfarmall

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SVcummins

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