SoCal Dave Posted March 13, 2012 Share Posted March 13, 2012 I twisted a 3/4" square bar three inches without difficulty. But, when I twisted the same bar 8 inches of twist, it was a great deal harder and I was surprised. It took a great deal more effort on my part to get it twisted to what I wanted. I wanted to do 10 quarter turns but only got 6 done. For the 3" twisted I heated the bar up with my oxy/acet torch with a rose bud tip. That worked fine. I used the same technique and heated it to the same orange heat but man what a difference a few more inches make. It appeared that the oxy/acet torch wasn't going to get it much hotter as I went back and forth. Not having lots of experience with twisting, I thought I should try a two burner forge, (borrow a friends two burner), or a bigger rose bud tip. The other aspect is that I had the bar in a leg vice while heating. I was aware of the heat sink the vice caused and made sure I heated that end last. The 8" twisted turned out OK, but I want to do 10 to 12 inches next and don't think I can manage it using my last method. This was a one man operation. Any suggestion. Quote Link to comment Share on other sites More sharing options...
MRobb Posted March 13, 2012 Share Posted March 13, 2012 Dave, I don't know what resources you have, but if you know any plumbers you might borrow a threading machine to turn it with. I have a Ridgid 300 machine that has torque you wouldn't believe. You would have to heat the whole area in a forge and then quickly clamp it in the machine. I'm not sure if your rose bud torch would heat it up that well. I have no experience with one. Keep us posted though. I would like to know how you end up. Mitch Quote Link to comment Share on other sites More sharing options...
Rich Hale Posted March 13, 2012 Share Posted March 13, 2012 My guess is lack of heat is one problem..set up and how you twist the other ones. Steel loses alot of heat into the air, maybe more importantly here is it loses a lot of heat into the rest of the bar, and or vise. I have two twisting wrenches I made from adjustable wrenches, Largest is 18" and handle welded on end to double the length. I preadjust the size and set the vice jaws so i do not have to fuss with either while losing heat. With two hands I can put al ot of force on the twist. That bar is going to have to have a lot of heat along the length of it to twist. And a lit rosebud held safely close by will help if it darkens a little or to help even up the twist. TRy doing a drey run a couple of times. withouit lighting forge, pull bar ouit put in vice and fit tool and grab like you are going to twist. Get the moves down to help with heat loss. Quote Link to comment Share on other sites More sharing options...
John B Posted March 13, 2012 Share Posted March 13, 2012 Let the material soak so the heat is all the way through to the core of the bar before starting the twisting and a really high heat is better The longer the twisting wrench (and double ended) the better The quicker you can turn the wrench the better Another problem with long twists if using a vice is keeping it straight, and having a good standing stance to get maximum purchase on your twisting wrenches, One simple thing I found useful was to slide a reasonably close fitting tube over the bar cut to the length of the twist you want to make, immediately after you have positioned your lower mark in the vice then you will get repeatable lengths, it helps keep the twisted section straight, and it also helps retain heat as it shrouds the bar from open air. (I had a selection of different legth and diameter tubes in a box reserved for this purpose) The tighter you get the twist the harder it seems to twist, Have fun Quote Link to comment Share on other sites More sharing options...
Greenbeast Posted March 13, 2012 Share Posted March 13, 2012 One simple thing I found useful was to slide a reasonably close fitting tube over the bar cut to the length of the twist you want to make, immediately after you have positioned your lower mark in the vice then you will get repeatable lengths, it helps keep the twisted section straight, and it also helps retain heat as it shrouds the bar from open air. (I had a selection of different legth and diameter tubes in a box reserved for this purpose) Nice suggestion! Quote Link to comment Share on other sites More sharing options...
Don A Posted March 13, 2012 Share Posted March 13, 2012 I had to twist some 1" by hand not long ago. I normally twist 1/2" or less at what I would call a decent orange heat. I was straining my guts out on the 1". I went back into the forge and let it come up to a bright yellow heat and then I could move it. It was still tough, but it would move. Great hint on the tube, John. I'll definitely be trying that soon. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted March 13, 2012 Share Posted March 13, 2012 When things get tall they can be a pain to twist. I usually twist long twists horizontally in my big vise---and then I can straighten using the screwpress and a couple pieces of wood---lots of flame and smoke but it keeps the edges from being damaged. If your piece design fits it you can put a support outboard of the vise with the twisting wrench just inside and use that to help keep things aligned. For heavy work I have a large twisting wrench---I once put a twist in a RR spike *cold* with it. Gets used very infrequently but when you need it you need it! Quote Link to comment Share on other sites More sharing options...
Ten Hammers Posted March 13, 2012 Share Posted March 13, 2012 As suggested, you need a forge. Soaked heat. John's suggestion of tubing over the heated bar is good. I have a stock stand ( 1" pipe upright with a collar and bolt, 3/4 riser to be clamped at height needed with a piece of 1" angle welded on top at 90º, centered, about 9" long ). Whew. Maybe you can understand that. This stand is placed beside the leg vise. Stock is set up ( cold ) in prep for twists. I'm right handed, so right side of vise. Frog eye ( thank you Rich ) marks the left end of the twist. Another marks the right end of the twist. The stock stand is placed at the right end, leaving room to start the twist on the right mark and supporting the rest of the bar. Left end in vise is paralell with part supported on stand. Make your twist and the right end over stand will perhaps move a bit but you have a straight plane to plumb with. BTW i just use an 18" crescent to twist bigger stuff in the shop. I should have another camera. Maybe a feller at work can take a pic and mail it to me. I made a fork from 3/4 COLD rolled at an event a few years ago without the stand. Split the tines and just heated the twist area and stuck some tongs in the (now cold) tines. Trailer shop has a leg vise. I also have a piece of ( likely 1 1/8 ) PTO shafting that was twisted COLD ( and cut off by me for repairs) by a 100+ hp tractor (likely was on a brush cutter).Well then will see if I can load these pics. Sorry they so big but this new unit really doesn't have an editor that I can find to use. Mebbe Glenn can hack them down a bit. Pic one shows the twist. 3/4 cold rolled. Work done in lump charcoal. Pic 2 shows the whole fork. Pic 3 shows the fork itself. This stuff has to be bloody hot to twist and/or reverse. CORE heat. Not really that large of a thing to do. Just prepare and get the heat. I hear of folks having special twisting wrenches and this is fine. I have described how I did this one above. Likely a coffee cup with water for the isolation quench for the reverse. I use tongs to twist 1/2 and below (at events and mostly at the home shop). As noted I DO use an 18" crescent sometimes in the home shop. To each his own I suppose. One fella asked me why I would waste a perfectly good piece of 3/4 cold 4 feet long and I said " because I can ". Quote Link to comment Share on other sites More sharing options...
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