latvius Posted December 17, 2006 Share Posted December 17, 2006 Hello, I am making some table legs and with the bottom part a ball shape. I spent a lot of time heating the ends and striking the bar onto a flat metal surface on the ground, It worked somewhat but part of the problem is I use a gas forge so when I heat the end of the bar it heats about the bottom 4-5 inches and when I try to fatten up the end, the bar bends. So I got an idea of sticking it in a vise, leaving about 2 inches out and beating the crap out of it. It worked but I'm not sure that was the best way and the results don't look as good as I had envisioned. Any advise on how to fatten the ends of the bar enough to have a good amount of material to make it into a ball? Also when I put the twists in I noticed the twist closest to the vise looks tighter than the twist where I had my wrench. Any advise on how to fix that? I attached some pictures to help explain. Thanks in advance! Quote Link to comment Share on other sites More sharing options...
tbrforge Posted December 18, 2006 Share Posted December 18, 2006 I understand the problem with the gas heating a wide swath. as your piece comes out of the forge, localize, pour water where you don't want the heat and vice it up and upset it. To quote a wise smith (Steve Kayne) upsetting is just plain upsetting Quote Link to comment Share on other sites More sharing options...
Mike Turner Posted December 18, 2006 Share Posted December 18, 2006 I agree with tbrforge I would quench up to where you don't want the heat and vice it up and upset it. If yo don't want to beat yourself to death trying to upset it, I would fold it and forge weld it till you have the desired size for your ball. On the twist I have seen guys doing long twists and they use a torch to keep the bar hot as they twist it. Quote Link to comment Share on other sites More sharing options...
habu68 Posted December 18, 2006 Share Posted December 18, 2006 Another trick is to place the part horizontaly in the vise at the limit of the upset, to localize the heat and get a better grip on the piece. quick light strikes will upset only the end, hard heavy strikes will upset deeper into the part. Quote Link to comment Share on other sites More sharing options...
Sam Salvati Posted December 18, 2006 Share Posted December 18, 2006 Coal forge.. HAha but seriously, You can do the quenching thing, that works good. the vice thing works good too, Just keep one hand on the vice spinner to keep it from sliding down into the vice. Or you can form a small neck on the bar and then do the vice thing, that works great! Quote Link to comment Share on other sites More sharing options...
mike-hr Posted December 18, 2006 Share Posted December 18, 2006 This sounds strange, but to do an upset like that, first taper the bar, if it's a 1 inch bar, do a taper to 5/8 or so, 3 inches of taper. Have an anvil or big chunk of steel on the floor, use the bars weight to do the work. Start off with 5 feet of material so it's easy to handle, cut the excess off later. By tapering the bar, you direct the force of the upsetting blow to the center of the bar, and won't mushroom the end. When the end starts to mushroom, correct it by chamfering more. When you correct the wiggle in the bar, the bottom edge will pronounce one edge proud, most likely. You can use the proud edge to direct more force to a thin area in the upset. I took a week long class this spring on traditional gate construction. We spent a day on upset heel tenons. It was a loong Wednesday , but it all made sense after 60 or so heats. Find a way to do localized heating, use a wet rag on the bar with a gas forge so you don't wiggle the bar more than you have to. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted December 18, 2006 Share Posted December 18, 2006 Things twist tightest where they are smallest in cross section *or* hottest, cool the section when it's "right" to let other places twist more. Quote Link to comment Share on other sites More sharing options...
henerythe8th Posted December 21, 2006 Share Posted December 21, 2006 Lat, Chances are you can't "fix" your twist... If you mess with them, you'll mess them up! you need to make sure that you have them heated consistently because the steel will work more/easier where the temp is higher. I generally use a twisting jig and my small Hybridburner as a handheld torch to heat where I want, then twist... Henry Quote Link to comment Share on other sites More sharing options...
Candidquality Posted December 21, 2006 Share Posted December 21, 2006 The changing twist is actually a benefit. You can tell stories of how you worked long and hard trying to get that gradual change to make the legs appear longer. That would be called marketing. Even heat is the key to an even twist. Never seen anyone take the time to fix it so I don't know if it's possible or worth the effort. Just take it as a lesson learned for next time. Quote Link to comment Share on other sites More sharing options...
the_sandy_creek_forge Posted December 21, 2006 Share Posted December 21, 2006 Lat, check out blueprint BP0276. It is a rivet header that Mr. Jr. Strasil created, but i have found that it works exceptionally well for upsetting also (haven't tried it with anything larger than 1/2 in though) The problem that i was having was that the flat jaws of the vise were digging in as i was upsetting whatever and making flats and cold shunts just below/above the upset. This device clamps and supports the stock all the way around and seems to work great. I should mention that when using it to upset, i am using a fairly light hammer (1 or 1.5 pounds) and using many rapid blows. I can usually upset 1/2 inch round to 3/4 inches in one heat, to 5/8 inches in two heats. Hope it helps. BTW Thanks for the idea Mr. Strasil It works wonderfully. -Aaron @ the SCF Merry Christmas and a happy and safe (even if it is crazy) New Year! Quote Link to comment Share on other sites More sharing options...
the_sandy_creek_forge Posted December 21, 2006 Share Posted December 21, 2006 shoot. just realized you were working with square stock and not round. The idea would still work, but the tool would probably require some machining or carefull grinding/sawing/filing to keep the desired grip on the still. Not impossible,just a little more time consuming in fact, i think i'm gonna make one for square stock just to see how it works out...after i finish the christmas gifts, and the railing project i just picked up, and the railing project for our house (since the wife liked the samples i made for the paid project soooo much;) ). Maybe I'll just put it on the to do list... -Aaron @ the SCF Merry Christmas and a happy and safe (even if it is crazy) New Year! Quote Link to comment Share on other sites More sharing options...
latvius Posted December 21, 2006 Author Share Posted December 21, 2006 Thanks for all the great advice!!! I'll do my best to put it to good use. Quote Link to comment Share on other sites More sharing options...
Dutchmancreek Posted December 22, 2006 Share Posted December 22, 2006 If your gas forge is hot enough, the best way to add enough mass to make a ball is to fold over the end and forge weld it. I find this is easier than upsetting. I also have seen, but not tried, a collar welded around the end and then formed into a ball. Even twisting depends on even heating, but just because the twist isn't completely even doesn't mean it doesn't look good. Steve Quote Link to comment Share on other sites More sharing options...
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