I recently built a tube bender which required some custom dies, so I searched around and found a neat way to make them on a lathe. Here is the result and how the fabrication process works.
VERY good piece of advise. Some of the chips of this part are long and razor sharp. I hope I didn't do this here without realizing, I do have some pliers to hand I was using which make an appearance here and there.
my humble suggestion about the procedure of this work,if firstly make a "v"groove near to required dimension with the compound rest ,and make a rough shape radius groove using a radius tool, finally finished that the job with the tool you can used in this video showing .it may reduce your physical effort and get more speed to finish your job.any way it is very great effort you did.👍
Nice work James. I was just in a shop yesterday getting a demonstration of a tube bender at work and my immediate thought was how to make my own dies for different sized materials and different finished curvatures. I will also need to make straight followers and there was your RU-vid - half the answer waiting there for me. Well done. The material you used, was it cast iron? Now the next step, making the follower which has a straight section with the matching curve may be a challenge. I was thinking of holding the work end on in a vice and machining on the mill with a boring bar and slowly working outwards with the diameter set in a similar way to how your cutting head ran on the lathe. Any thoughts?
Hi, the steel is EN3B. I've been thinking about a straight follower myself, my plan was to use a ball end mill of the same size as the tube done horizontally on a mill, possibly moving side to side a little at the end to get a slightly larger radius. I'm sure a boring bar would work too.
James, soon I will be lucky enough to collect a second hand tool and cutter grinder from a die making machine factory that was happy to part with one for a good price. The best thing about this is that I will also be able to learn from the staff there how to make stuff on this useful tool. Maybe I could shape a tool that could go on the milling machine that would cut the curve quickly, like a large format ball end mill. Rough it out with a boring bar and finish with the super-sized ball end cutter. I also picked up some super sized drill bits and reamers from a second hand machine shop that is going into liquidation. All I need is an 1-7/16" drill bit and 1-1/2" reamer and slice the end result down the middle and the job would be done quickly. Now all I need is a huge drill press that has a morse 5 or 6 taper head. Not sure if they come that big but that I cannot justify. It never ends. However, today I picked up my markup table that was surface ground across the full width {900mm} with what looked like 2/3rds of the width of the slash grinder disc. The finish is beautiful and smooth. This factory has huge machines. Makes mine look tiny by comparison.
Other than the terrible WAAAHHHH noise of your lathe in my headphones, this is fantastic! Now I need to try this. So, I need to make a jig for my crappy Atlas and 2; make sure my steel supplier doesn't screw me for the blanks! Thanks for the video.
Yeah, sorry, it's quite a noisy motor, I took off the old one and replaced it with a larger one which is much louder than it was standard. Some metal suppliers will chop short lengths (2" minimum or so) off a large diameter round bar for parts like this.
The dies I made create a circular channel for the tubes, I went with 0.010 clearance which is 1% of the tube diameter and also the tolerance the tubes are made to. They work just fine.
Very nice James. I notice you made dies for different tubing diameters. Did you end up making different sized insert holders and extra posts to manage the different diameters? If the insert holder could slide back and forth and be adjustable (kind of like those lantern style lathe tool holders) would the rigidity be a concern? Thanks, nice video.
That lathe is sold in the US as a Smithy & various knock offs with a mill head, total crap, poorly engineered & worse manufacturing . Do you have some kind of backgear? Mine did not & while you could swing 12" you couldn't turn more than 2-3 because the speed was too high unless you bought their uber expensive planetary reduction sheave.
£300 quid I paid, amazing what you can do with it if you're patient. Usually very patient... 180rpm is the slowest you can go with the standard belts on mine, carbide tooling at this radius is fine.
seen someone use a adjustable holle cutter (for a mill ) for sumtin like this , there adjustable so you can make the radius any size you like using the same tool
That steel is basically SAE 1020. You wont get any hardness to it. See if you can find someone who does industrial hard chrome single step. About .0100 mm.or .0005 inch. It doesn't need to be hammer hard or thick. Just slippery hard if that makes sense.Especially with stainless pipe. It'll gall like hell on plain steel or another piece of stailess but slide right over hard chrome or that Delron some dies are made with
Would it be an idea to increase rpm to compensate for large diameter (with carbide insert). Maybe get better chips and be quicker? Any pros know the answer?
he talked about it going 600ft/min. That would be about the right speed for any steel that you can harden or 4140 and 4150. For just mild steel it would be a little on the low tho.
