Q About Indexable Cut Off Tools

kingmt, no can do unfortunately - it doesn't have pulleys, only a rheostat that slows the motor, presumably reducing its torque at the same time. It's pretty weedy - I can pick it up off the floor with one hand if I have to!

thanks for the feedback ogberi, that's very helpful. I got a couple of Morse 8/10tpi bimetallic blades from that Morse free trial offer, so it's worth a shot.
 
also, thanks to Mikey I'm going to think about a rear mounted parting blade as another option, even if only for small diameters. He suggested P1 or P1N blades (1/16 and 0.04" think) which should work well given that they match the thicknesses of a couple of tools I've ground myself. Is there any benefit to going to cobalt (M42) over HSS for either of those blades? The cost is around double, but it's not like I'll be using a lot of them, as long as I don't snap them.
 
A rheostat on a motor is a really bad idea. It not only cuts the torque but will burn up the motor. Someone posted a video the other day with the parting tool turned upside down & cutting above center letting the chips fall down away from the tool instead of building on top of it. The way it was explained made a lot of sence but I haven't tried it yet.
 
kingmt01 said:
A rheostat on a motor is a really bad idea. It not only cuts the torque but will burn up the motor. Someone posted a video the other day with the parting tool turned upside down & cutting above center letting the chips fall down away from the tool instead of building on top of it. The way it was explained made a lot of sence but I haven't tried it yet.
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I think it's probably a universal (series) motor and the rheostat controls a thyristor that varies the voltage.
 
juiceclone said:
Cutoff/parting tool..HarborFreight "tile" blade I think it was. about $10 does NOT flexView attachment 103817

A friend of mine who operates a medium size machine shop near me uses the same blade on his CNC mill for slitting work. He also uses some of the smaller HF saw blades too. They work great in 41410 low and high heat treat materials.
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mattthemuppet said:
also, thanks to Mikey I'm going to think about a rear mounted parting blade as another option, even if only for small diameters. He suggested P1 or P1N blades (1/16 and 0.04" think) which should work well given that they match the thicknesses of a couple of tools I've ground myself. Is there any benefit to going to cobalt (M42) over HSS for either of those blades? The cost is around double, but it's not like I'll be using a lot of them, as long as I don't snap them.
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Nope, HSS works for most common materials.
 
thanks Mike! went and procrastinated for a bit by looking at the lathe to see how i could install a rear mounted cut off blade. should be doable with my plan to replace the compound, but annoyingly the 2 bits of stock i have are either too thin or too thick, so I'll have to do some more head scratching..
 
Karl_T said:
Don't want to offend you, but a 6x18 lathe is likely not rigid enough to run cutoff inserts on one inch shafts.

Save yourself some money and grief. Cut it with a hacksaw and face.
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I quite agree with you; insert parting is for industrial machines; I'd stick with HSS parting tools for small lathes; I especially like the T type, as they bind much less in the cut. I have both HSS and insert tools, and tend to use the HSS for smaller work. In my opinion, one should NEVER count on a parted cut as a finish I always plan to face the part off after parting, except when working on a turret lathe, where the cut is much more rigid and accurate and well finished cuts are much more possible than on engine lathes.
 
Parting with HSS bigger pieces is hard with my 13x24. You have to worry about binding the tool, heat, cooling etc.

Much easier to do it with a band saw.

Of course very hard material will kill the band saw blade fast and not a carbide tipped tool but that is going into speciality territority.

If using HSS cut-off tool make sure not to be too aggressive - I managed to get the spindle to stop when some debris got stuck in the channel on a 1/8 inch custom made HSS "grove tool". I was a bit shocked nothing broke and that somewhat tiny 1/8th by 3/8th piece of HSS wasn't affected at all.
 
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