Straightening stainless steel rod/wire

Hello all,I have been given a 4 meter length of 3.2mm stainless steel wire, unfortunately it has come off a roll so it is curved. What is my best way to straighten it so I can get some useful lengths! I don't now what the spec of it is,but I have been told it is what they use for dropping down the well for wire lining whatever that is.

Regards Mark P

You can buy very nice (and expensive) wire straighteners but a trick I have used is a piece of pipe with a slightly larger diameter which has a bend or nick in it set in your lathe chuck. The lathe is set a slow speed while the wire is pulled through the pipe. It works fine for small diameters but 3.2 mm is thick wire so it may not work . Niko.

Your wire is a bit on the thick side but one way of straightening wire is to fasten one end to something sturdy, clamp the other end in a drill chuck and, leaning back give it a quick whizz. The other problem with this method is that being stainless the wire will work harden!

Bert

In his book Simple Workshop Devices Tubal Cain gave some advice on straightening copper tube - probably a less challenging proposition than stainless wire - which involved first annealing the material (unless you know the composition of your wire annealing it will be guesswork, of course). He then pulled the tube through "gag jaws" in the bench vice; these were made by drilling a hole through a piece of wood the length of the vice jaws and then splitting the hole with a saw so that the wood gripped the tube as it was pulled through. Another method involved using the lathe as a powered drawing tool in which one end of the tube is, in effect, hooked over the toolpost and the other end is pulled through the jaws of the chuck by operating the self-act.

In the past I built a machine to straighten coils of 304 or 314 stainless wire and cut it to length. Yes the wire does work harden quite quickly if the pull feed slipped on that machine in a second or two the wire was broken. The machine employed a rotary head supported in ball bearings the wire passed right through the axis of rotation. the head had adjustable hardened fingers that bent the wire very slightly as it rotated.

However I don't think using this method would work very well for a short length because it requires testing over several metres to get the speed and bend settings adjusted.

I wonder if the wire was stretched tight by clamping each end, maybe stretched along a steel bar from stock? It would need to be spaced away a couple of centimetres.

After stretching it could be heated with a propane torch to dull red while slowly moving the torch along. hopefully allowing the bends or camber to straighten.

There would be a bit of oxidisation but that could be polished off.

Regards
John

Hello Mark P

For reasonably short lengths of wire around a metre:

grip the wire at one end in the lathe chuck

Take a piece of hardwood say 300 long, 30 x 20 mm, with a hole in the middle a reasonable fit to the wire diameter

poke the wire through the hole, move the wood up close to the chuck, hold the hardwood at an angle to the wire, say 20 degrees

run the lathe at slow speed

slide the wood along the wire towards the tailstock

What you are doing is to yield the wire while it is rotating

Of course, eye protection, gloves etc.

Jim

Even at slow speed 900mm or so of 3mm wire poking out the end of the wooden block will wipp about quiet badly, watch yourself

Back when I was into archery I owned a simple arrow straightner. The principle may well apply here:

A base rail with two pairs of bearings that could be slid along, A central column holding a DTI and a central squeezable clamp to apply pressure. Rotate the arrow (wire) to find the high spot, adjust the bearing spacing for gentle or more narrow degree of bending .. squeeze the hand clamp by judgement - rotate wire to assess result and repeat until the arrow length was true. We'd expect to straighten a 2213 (220thou od by 13thou wall thickness) arrow to a half thou along it's length with practice. Too heavy handed and you risked denting them.

JasonB is right rotating the wire in the lathe could cause it to whip around, Or even wrap around your arm pulling you in. That could happen at slow speed, not good to think about.

Commercial wire straighteners do it in reverse the head rotates not the wire.

Regards
John

Have you tried fixing one end and give the other end a sharp pull? I used this method for prepping wire to make mail (chain mail). 3.2mm is thick but some sort of tensioner should do it.

12" lengths? Straighten roughly by hand, then lie it on a bit of kitchen worktop. Lie a heavy chopping board or similar on top and roll back and forth putting an increasing amount of weight on the board.

Works every time, as long as you can get it to start rolling and it is ductiukle enough (i.e. it hasn't got too much spring). Works on brass and copper pipe and even works on iron wire a couple of thou thick:

Neil

What are grooved rolls and did it work ?

I also have some 2mm and 3mm stainless steel rod. It has just arrived in the mail and some of it is a bit bent. As I want to use it to make piston rods, they should be as straight as possible. Of course I could just discard the bent rods and use the straight ones but I am curious if there is an easy way to get them straight.

One way to straighten wire is to apply a tensile load just enough to cause a permanent extension of length. For soften wire - brass, silver etc, it works a treat, but the principle is the same, you just need to pull harder.

Cheers, Tim

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A very wise decision, Mark

Don't cut it up yet though ... you may find some curved things to make !!

MichaelG.