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bar straightening recommendations

wmpy

Hot Rolled
Joined
Dec 16, 2011
Does anyone have any experience getting bars straightened? I have a large bundle of 20' long 7/16" OD stainless tubing that is not very straight.

The long story is that we normally run this job out of welded tubing. This time around, welded wasn't available, but the supplier agreed to sell us seamless tubing at the same cost. Usually it's more expensive. We thought the machinability of it would be better since we wouldn't be hitting the weld when boring the end, so we went for it. Also, we didn't have much choice since our usual material isn't available until next year. Well, the bars are bent pretty bad. And there's a lot of them. We cut these off in a lathe, and our bar support is making a terrible racket with these rattling around inside. We'll probably end up cutting the bars in half or thirds or however many pieces it takes to safely run them. I do remember reading somewhere on this site about getting bars straightened by an outside service. I know nothing about the process and whether it could be done economically on bars of this size. So if anyone has some experience with this, I'd love to hear it.

As a side note, we're seeing more and more where materials are unavailable- or at least unavailable in the time frames we're used to getting them in. Just this last week, I set another job that is normally run out of tubing from solid bar stock. And we're working on some short runs of steel parts out of solid bar stock that are normally from forgings because the forgings are not available until next year. I'm sure others are dealing with this too, but just take this as a reminder to order your materials way ahead of time- at least for the less common stuff.
 

wmpy

Hot Rolled
Joined
Dec 16, 2011
I contacted a company in my area that does bar straightening and was told that due to the thin wall (.065"), it was too risky for them to straighten the bars. It looks like we're fighting this on our own.
 

kustomizer

Titanium
Joined
Aug 17, 2007
Location
North Fork Idaho
Find a pvc, pex, cpvc. copper, some kind of tube to make a more appropriate liner for the bar support, I use any combination of the above to get a snuger fit and make the rattle go away
 

wmpy

Hot Rolled
Joined
Dec 16, 2011
Find a pvc, pex, cpvc. copper, some kind of tube to make a more appropriate liner for the bar support, I use any combination of the above to get a snuger fit and make the rattle go away

We actually brought out one of our old bar support tubes from the Brown and Sharpe screw machine days. It has a coil of lead (or some soft metal) inside it. Now you can barely hear it running. Before you could hear it across the shop in the PVC tube we were using.
 

jscpm

Stainless
Joined
May 4, 2010
Location
Cambridge, MA
You could put the tubing on a mandrel, then heat it to annealing temperature and see what happens. Would require a large, specialized furnace, however.
 

Mark P.

Aluminum
Joined
Sep 1, 2021
Contact Precision Straightening in Cleveland, Ohio. He used to straighten the magnesium weldment tables we made.
 








 
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