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Glowing hot hard turning.
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Previously:
https://www.homemadetools.net/forum/...791#post136958
https://www.homemadetools.net/forum/...384#post146537
https://www.homemadetools.net/forum/...5198#post81343
I would like to know some specifics on that set up. Workpiece material, cutting tool material, etc.
Saw similar thing back in the early 70's, but not glowing, in the Systems Engineering department in college. After the cut, the chips dak purple, radiating heat you could feel from 10 feet away. The workpiece was cool to touch. Was a big lathe fitted with a MONSTER motor. They were developing and testing ceramic tooling.
I've seen stuff like this before, and have been told it's fine for tungsten carbide inserts, but I have a hard time believing it. At least the surface finish is nice. Or maybe it's just spinning too fast to tell.
The finish on the workpiece in the demo I saw looked and felt polished, like a mirror.Quote:
Originally Posted by nova_robotics
When I first got my lathe I talked with my dad a good deal. He was in the plastic injection molding business his entire career. Both as a mold designer, product designer, and building molds in tool rooms. He told of a time that his boss set him up to hard turn. All of his learning in relation to tool and die work was "on the job training", some self taught. The hard turning was not going well so he asked his boss for advice. Boss asked if the lathe could turn faster, so my dad upped the speed of the spindle. This happened 2 or 3 times. By the time the work was coming out as desired the swarf was burning like the sparks off a cut-off wheel, he said the only bad part was the cleanup after the job.
You wouldn't want one of those chips changing colour behind your ear.
I've seen it happen with somewhat cooler chips coming off parent metal colour and one turning blue behind the operator's ear,........it was an interesting dance!
Yeah I wouldn’t want to be that close to that swarf as it’s flying off the insert like that...
That swarf looks a bit intense. I wonder if OSHA would approve of having that T-wrench perched on the tool post like that?
Hi Gang:
At the factory I worked at they made needles for fuel injectors this way: heat treat the bar stock and turn the needle hard. The next step was finish grinding and assembly. Before we would soft turn the needles, pre-grind, heat treat then finish grind and assemble. More steps but the real risk was finish grinding soft parts and assembling them into injectors. They would work well enough for a while, then the tip would leak, BAD!
They would heat treat the bar stock vertically in furnaces made for helicopter blades.
Carl.