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I’m interested in knowing the most efficient method of upsetting the end of ¾ and 1” square bars. The process of forming a 50% larger bulged end for table legs up to 45” long. I need a more productive way to accomplish this than, dropping a hot bar on end on a heavy plate on the floor, or hand hammering it while supported through a square hole in a big swage block.
I’ve been thinking about making a 50-75 lb treadle or pneumatic hammer, with the front of the anvil open and shaped like a u. Make the anvil from three very heavy bars or plates welded together. I could then place a removable die block with various square holes in it on the anvil and key it in location. This would support the bars to be swaged. The die block would slide out to the front of the hammer to allow install and removal of the bars. I could core drill a 2” hole in my shop floor to allow the long bars a clearance for their length. I’d pre swell the ends of the bars so they would stop in the die block in the correct location. You all have vast experience and I’m pretty new to blacksmithing. So I need to know if I’m missing something or any better ideas are out there . I’d use this hammer for other operation requiring top tools also.

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I think upsetting the bars the old-fashioned way is the best option, especially if you only want to upset them 50%. 45" of 1" square should be plenty heavy to upset itself by dropping.
However, failing that, what I would do is get a piece of 1.5" stock, draw down one end to 1", and weld it to your length of 1".
That might sound naughty, but it is actually much more traditional than all this epic drawing down and upsetting that people do these days, and does not necessarily involve a power hammer. And if you don't care about tradition, it is still a practical solution to your problem.

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I have a air powered chipping hammer .068" shank. I built a fixture to hold it to my platen table. The trigger is clamped shut and I use a foot pedal to actuate the hammer. I welded a pocket shaped die to the end of a chipping hammer bit (forged end would have been better) I just push the bar into the die on the end of the chipping bit and hit the foot pedal. I used this to upset the ends of 22' long 5/8" bars to 13/16" 3/4" from the end in one heat. The bar ends up being the anvil. The longer you leave the bar the more efficient this works.

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Actually John means .680 shank. If you're doing repeat parts around that length you could build yourself a fixture on an "I" beam with an adjustable backstop. Maybe even with a big screw and a spoke wheel to feed the work in.

Actually, if you secure the part well, you could make the same sort of fixture using a hand-pump hydraulic jack.

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I clamp the bars is my 8'' parker vice and use a .680 chipper that has a chisel modified to receive the bar. The receiver is simply a round cylinder that captures the bar. It's wider than the upset I need so it doesn't stick, It works pretty good for ends, even better for upsets in the length of the bar...

post-15096-0-96625300-1324351009_thumb.j

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The best way to do this will depend on how many you need to make....if it is production then make a machine or buy an existing machine for upsetting.
If you only need a dozen then coal forge or induction, leave them twice as long as needed for weight, stand on a layout table and drop them onto an anvil on the floor...1/4 turn per strike to keep it even and go till you get tired. I upset a run of 1x2 bar that way and it took a day for 20 of them.

Ric

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You could also mount your post vice horizontal (don't forget to support the foot) at a suitable height for a horizontal swing with a sledge hammer. Choose your height for either a golf type or chopping type swing, depending on which is more comfortable. You can also stand over and do a between the legs chop like you see the lumberjack competitors use. Probably not suitable for more than a couple bars as the powered options sound a whole lot easier.

Phil

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  • 2 months later...
I clamp the bars is my 8'' parker vice and use a .680 chipper that has a chisel modified to receive the bar. The receiver is simply a round cylinder that captures the bar. It's wider than the upset I need so it doesn't stick, It works pretty good for ends, even better for upsets in the length of the bar...


I got to thinking about the way I've done this in the past and I realized this post is hogwash cause if you put the hot end in the receiver they would become one.......It's been ahwile since I've done it and it all came back so here it is.......

First pic is a 5/8'' rd bar brought up to a welding heat at the very end. I put the cold end in the air hammer receiver, put it in the little cup swage below and let er have it while turning the rod constantly....!5/16 upset on the first heat.....Four heats later it was 1.25+....No corrective blows at all.
An induction forge would have been sweet.......
The 2nd pic shows the cup swage on a hammer bit and this is used for long pcs in a vice while turning bit constantly as well to keep the end true but that's not always the case.....The shorter the heat the better...... ;)

This can be used to upset in the length of a bar but as it is by hand it's allot trickier.

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post-15096-0-01097900-1330026166_thumb.j

post-15096-0-78103200-1330026208_thumb.j

post-15096-0-00840200-1330026238_thumb.j

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The parts are going to be table and bed post legs. Drawing out 3-4 foot and longer lengths would be a problem in this case. I'm going to start off dropping double lengths against a 2" plate on the floor through a tube (to keep them on location) attached to my welding table. I'll see how that goes and be looking around for a used jack or chipping hammer in the mean time. Thank you all for your suggestions and help

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Ok I went and tried a little upsetting and here is how it turned out. I first tried upsetting by dropping an 8 foot 3/4 square bar heated orange hot onto a large steel plate on the floor. It bent all over the 4” long heated section… well duh. Tried it again cooling everything but the last inch, this work some but I guess I would need to do 3 or 4 heats to get what I’m after. So tried it again this time using a 6X pneumatic riveting hammer that I have with a 3/4 flat round tool.I really thought the thing would be way too small for the job. Well low a behold it worked like a charm. In one orange heat, held in my 6” leg vice and not even backed up on the other end , it upset like a dream to 1.270. I was VERY surprised. I’m sure with the other end backed up. It will work even better. This took about 45 seconds to do an in only one heat.I tried AGAIN to post pictures without any luck. I’ll try again later.

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Also, orange isn't very hot. Short and very intense heats will get the most sideways growth with the leas bending.

I'm not sure what you're trying to achieve with the guide, but it probably isn't important now that you've broken out the rivetting hammer.

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  • 2 weeks later...

The key to all blacksmithing which I have to remind myself when I am having problems is, "let the heat do the work"!

When upsetting, controlling heat creep is crucial. I find it much easier to heat with the oxy acetylene torch rather than using the hearth and trying to quench back to isolate the movement area. You can even hit while continously playing the torch on it, especially when upsetting mid bar.

+1 on the hand held air hammers as described above

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