03-11-2017, 10:52 PM
I finally completed new dies for my Hossfeld-clone JD2 bender. 5" round, with the roller and offset holder block.
I went to my local metal merchant who sells drops & surplus material (in addition to new material) and picked up some mystery metal - a 2.5" thick x 6.5" round for the die, a 3' length of 2" round, and a rectangular block about 3x4x5.
Turned out the big round (which needed 1.5" taken off the OD) was some kind of wicked, evil, nasty stainless alloy. I was using my ABOM79 style HSS roughing tool (5/8" square tool stock, it's burly!) and it was putting out these stringy chips.... smoking hot 3/8" wide stringy chips @ 33 rpm. :) That's a huge grin, and the 7hp machine isn't even breaking a sweat. It all went to heck in a handbasket after I tried to put a chip breaker onto the tool - a slim groove just behind the cutting edge. The edge began breaking down, the chips were getting hotter -- in fact, so hot that I had a squirt of low-sulphur cutting oil burst briefly into flame! Couldn't seem to get my mojo back with the roughing tool and switched over to a carbide tool with geometry for a shallow cut. Took forever, but it worked out OK.
Then the drilling fiasco. Center pop - went fine. 1/4" drill - went fine. 3/8" drill - after putting a fresh edge on it, went fine. Dropped the speed, and went up to a freshly sharpened 3/4" drill, and managed to thoroughly melt it within 1/2" of drilling! I cut it off and set it aside for sharpening later. Switched over to a 5/8" drill and that went fine. Then switched over to the carbide boring bar to open the hole to 1" This also took forever, but worked out OK.
I'll try to load pix tomorrow when I make bends for a railing I'm working on.
I went to my local metal merchant who sells drops & surplus material (in addition to new material) and picked up some mystery metal - a 2.5" thick x 6.5" round for the die, a 3' length of 2" round, and a rectangular block about 3x4x5.
Turned out the big round (which needed 1.5" taken off the OD) was some kind of wicked, evil, nasty stainless alloy. I was using my ABOM79 style HSS roughing tool (5/8" square tool stock, it's burly!) and it was putting out these stringy chips.... smoking hot 3/8" wide stringy chips @ 33 rpm. :) That's a huge grin, and the 7hp machine isn't even breaking a sweat. It all went to heck in a handbasket after I tried to put a chip breaker onto the tool - a slim groove just behind the cutting edge. The edge began breaking down, the chips were getting hotter -- in fact, so hot that I had a squirt of low-sulphur cutting oil burst briefly into flame! Couldn't seem to get my mojo back with the roughing tool and switched over to a carbide tool with geometry for a shallow cut. Took forever, but it worked out OK.
Then the drilling fiasco. Center pop - went fine. 1/4" drill - went fine. 3/8" drill - after putting a fresh edge on it, went fine. Dropped the speed, and went up to a freshly sharpened 3/4" drill, and managed to thoroughly melt it within 1/2" of drilling! I cut it off and set it aside for sharpening later. Switched over to a 5/8" drill and that went fine. Then switched over to the carbide boring bar to open the hole to 1" This also took forever, but worked out OK.
I'll try to load pix tomorrow when I make bends for a railing I'm working on.