Chromoly tube specs ?

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cuslog
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Chromoly tube specs ?

Post by cuslog » Sat Sep 07, 2013 12:39 pm

Just an amateur here.

Built a chromoly cage about 14 years ago, bought the tube from "Chassis shop", was nice tubing. "Mill scale" was very smooth, almost looked painted, "heat numbers", mill name etc. printed directly on the tube.

Now, I'm adding front "strut bars", ordered tube from a "tubing supply house", it arrives and its not nearly as nice as the first batch. Rougher finish, surface rust, no heat numbers etc.

It all measures what it should be and I'm not doubting that it's chromoly. Main cage is already Cert'd and its just an 8.50 car so I think it'll be fine.

Just wanting to know what I should ask for next time if I want "the nicer stuff". This is just a couple of 6 ft. pcs., easy enough to clean up and paint them. But on a full cage build it could be quite a bit of "cleanup". Or possibly even Cert. problems.

IIRC the faster Cert's need to show heat #'s etc. ??

BigBlocksOnTop2
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Re: Chromoly tube specs ?

Post by BigBlocksOnTop2 » Tue Sep 10, 2013 7:50 pm

Ask for ProMoly.

cuslog
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Re: Chromoly tube specs ?

Post by cuslog » Wed Sep 11, 2013 11:57 am

Did a bit more research since the original post.
The tube I got in my original purchase was made by "Plymouth Tube".
I see the Chassis shop web site says their tube is all "milspec xxxxx".
The most recent tube I got was from a generic tubing supplier and I'm guessing that it was made offshore, probably China or India.
Visually, not nearly as nice as the Plymouth tube (which I'll ask for by name next time).

Barbapapa
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Re: Chromoly tube specs ?

Post by Barbapapa » Wed Sep 11, 2013 2:11 pm

Plymouth tubing is highly regarded and should be US made. I've seen 4130 tubing that has different finishes every time I order and that's US or German tubing. Rust is unacceptable though, your supplier shouldn't have let that ship.
Mike S.

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