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adrian
11-18-2010, 01:51 PM
My steel supplier has cold rolled tube in several grades. The sizes best suited to my project are available in both "Drawn Over Mandrel" (DOM) and "Cold Rolled Electric Welded" (CREW) grades.

Does anyone have any experience working with either? Are there significant (or any) mechanical or cosmetic differences between them?

Thanks.

savarin
11-19-2010, 06:26 AM
Check here for a full breakdown.
http://www.rockymountainextreme.com/showthread.php?t=2886
DOM from all accounts can twist when bent due to the stress thats built up when pulling over the mandrel so your bend may point off to one side. (I dont have any experience here)
Cost wise there may be a difference but shouldnt be a huge one.
CREW or HREW are what most of us use.

adrian
11-19-2010, 01:17 PM
Thanks.

My understanding is that cold working improves strength and finish dimension, but that's a good tip regarding stress build-up in the DOM process. Looks like CREW is my best bet.

Cheers,
-Adrian

adrian
11-22-2010, 06:33 PM
It turns out there is a significant cost difference. My supplier is quoting $0.29/foot for 1.75"x.065" CREW, vs $1.39/foot for 1.5"x.065" DOM. Plus the DOM is a special order, so I'd have to buy full length (between 18-20') which is way more than I need.

Makes the decision much easier.

adrian
11-22-2010, 10:23 PM
Correction.


It turns out there is a significant cost difference. My supplier is quoting $0.29/foot for 1.75"x.065" CREW, vs $1.39/foot for 1.5"x.065" DOM. Plus the DOM is a special order, so I'd have to buy full length (between 18-20') which is way more than I need.

Makes the decision much easier.

Of course, those numbers were per inch, not foot. It works out at $3.48 per foot for 1.75" CREW vs $16.68 per foot for 1.5" DOM.

Still an easy decision, but I hope my misquote didn't have you all rushing to Canada to buy amazingly cheap steel tube.

-Adrian

badcheese
11-23-2010, 01:58 PM
If you're lucky enough to live near a steel supplier, find out if they sell remnants. You probably have to pick through the racks yourself, but you can get much lower prices that way just because the pieces aren't full lengths.