|
|
Back in the 70's, I was forced to use .042 MIG wire for fine O/A welding and never took the time (internet did not exist) to figure out how to straighten wire. (straight filler rod lets you do so much more as control is concerned.)After a couple hours on the internet and actually making some rod, this is the best way to do it in my opinion>Wooden Block MethodThe biggest problem will be finding a drill of lathe chuck that will grip .042 or smaller - most chucks are designed to grip no smaller than 1/16 inch.I worked with 2 ft sections and you'll see why in a moment.METHOD:Manually straight wire to the best of your abilityChuck about 1/8" into your drill or lathe (floor standing drill press might be good too)Get piece of wood 1 or 1.5 inch thick at least 12 inches long and drill a 1/16 hole in one endSlide the wood over the wire till you get to the chuckPut a welding glove on the hand holding the wood because the wire is going to whip about!Start the chuck and draw the wood along the wire at an angle (about 70 deg from the chuck axis) sufficient to cause bending of the wire as it is pulled through the holeRemove the wire and put the free end into the chuck and repeatThere are videos of this on Youtube (I probably should have linked to one) that show this process.What does not work (wire breaks) due to the strength and stiffness of the wire:Yielding wire by stretching (pulling) - while this should work, you don't want to be around when it breaks. I had wire pulled on my bench lathe and it plucked like a piano string and while a major amount of straightening did occur, the wire still had about a 1-2' radius. I even have 2 shop vises about 7' apart and I was pulling by swiveling one with a 3' crowbar. You could get some yield, but not enough before it would break. (The resulting bends in the wire at the clamped end due to the shock wave were quite entertaining!)Twisting wirePulling and TwistingOf course you can buy TIG rod at least in .030, .035, .042 nowadays for $3 a pound, BUT if you have a spool or MIG wire that you will never use, you can straighten wire as you need it.I have to laugh, for the smaller wires, the sheer quantity of rod you get for a $3 pound makes the labor involved per pound, astronimical!But then, welding up automotive sheet metal is about the most unprofitable task there is (except for rolling out a new fender maybe.)
Reply:You either pull it through a bunch of straightening rollers, or stretch it about 1/8" per foot.Welding/Fab Pics: www.UtahWeld.com
Reply:I have to disagree with one statement...you said twisting doesn't work. Zap demonstrated for us in the TIG clinic how to straighten wire by clamping one end in a vice and the other end in the drill check and fire away. He repeatedly made MIG wire perfectly straight for TIG usage.Miller Multimatic 255
Reply:Puling .042 steel wire with a yield strength of 60ksi results in 423 pounds of pull to reach the yield point. If you actually try this, the wire will break where clamped due to notching. You might be able to achieve this with collets but who has the ability to pull between 2 collets? And if it does let go, you do not want to be there.Vise jaws don't work. The only thing that does work to a point is a Rohm drill chuck which has simple line contact jaws - you can grip a #60 drill with these chucks. I tried stretching on a bench lathe and got the wire to pluck like a piano string and still, that was not enough elongation. I decided to abandon this method due to its inherent danger.As far as straightening rollers go, they are expensive and let's face it, someone straightening MIG wire to use as filler is a Cheap Skate these days (of course back around 1970, you couldn't buy <1/16" filler from your local welding supply shop so they weren't Cheap Skates back then.)There is a lot of wire straightening going on in the RC hobby. Those guys fabricate all kinds of links, rods, etc. and have to learn how to straighten wire.Last edited by Cardinal Grammeter; 05-27-2014 at 03:42 PM.
Reply:I have done the cordless drill and vise way to straighten mig wire for 25+years and don't have problem whatsoever.Why all the problems? Chuck doesn't go small enough on your drill,then just double the wire over itself and tighten the chuck.Breaks at the vise because you are pulling the wire at 90 deg from jaws.Tighten the wire and pull parallel to jaws.This is not rocket science just think outside the box.Only do about 10 ft at a time.Result straight as an arrow,V
Reply:Vinnie, thanks for the suggestions.Unfortunately, I started out doing exactly what you said.This MIG wire I'm using work hardens almost instantly and breaks off at the drill chuck every single time I tried with the wire folded over, wrapped on the threads of a screw, and gripped between two adjacent chuck jaws.I have 2 vises I can pull between, I can get some stretch but when I try to get enough stretch, it breaks. I can get the wire straightend from about a 2" radius to about a 2' radius which is still not good enough.I bot this wire in the 1980's and haven't checked to see its alloy, but when I got it, it was for general steel welding.I haven't tried pulling with copper jaw protectors in the vises since I've only made a set for one vise. Maybe that would give me the edge that I need. FYI the vises are an 8" and a 4" and I could experiment with minimal clamping.Obviously, pulling would be the easiest.I wish I had 2 Rohm chucks that can grip down to nothing - only have 1 for my lathe (and maybe another on my drill press) - I'd like to try to pull on my bench lathe but is dangerous where you have to put your hand to crank the tailstock. I even tried pulling and twisting on the lathe with non-Rohm chuck on one end. Wire breaks at the chuck quickly.I don't know if I specifically said that my objective is essentially straight when done..ThanksTom
Reply:take two pieces of .023 wire and twist them together, gets you something smaller than 1/8 and ends up reasonably straight |
|
发表于 2021-8-31 22:26:23