Models for grinding HSS Lathe Tools

With that kind of tolerances, you need to bore it. A drill or end mill will not net you that kind of precision. Given that there is a hole in the bottom of the bore, you will not need to get the point of the bar to get to center and you can get away with a larger bar without running it into the wall of the bore. I suggest a 3/16" diameter Micro 100 solid carbide bar that can cut to your 1.5" depth. It will take micro-cuts to allow you the kind of precision you require.
 
With it being such a tiny lathe it makes it hard to hold much bigger then a 1/4" shank.
 
mikey said:
With that kind of tolerances, you need to bore it. A drill or end mill will not net you that kind of precision. Given that there is a hole in the bottom of the bore, you will not need to get the point of the bar to get to center and you can get away with a larger bar without running it into the wall of the bore. I suggest a 3/16" diameter Micro 100 solid carbide bar that can cut to your 1.5" depth. It will take micro-cuts to allow you the kind of precision you require.
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So is carbide ok to use on little lathes like a watchmakers? It would be considered to a sherline i believe or a unimat.
 
Brento said:
So is carbide ok to use on little lathes like a watchmakers? It would be considered to a sherline i believe or a unimat.
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No problem. Those micro 100 bars are crazy sharp and cut as well as a honed HSS tool. The ones to avoid are brazed carbide unless you have the gear to shape and hone them. Inserts generally come kind of dull too, but you can get polished versions. On a lathe that small, you are probably better off skipping those as well. @mikey has a Sherline, so he can speak from more experience.

The micro 100 bars I have don't have flats. You can just set them up with the angle you need. I'm sure they have some guidance on the recommended angles, but I just start a few degrees off horizontal and adjust if needed.
 
Brento said:
So is carbide ok to use on little lathes like a watchmakers? It would be considered to a sherline i believe or a unimat.
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Brento said:
Do the micro 100 bars have flats on them?
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Carbide bars are fine for even small lathes. They are very sharp and cut quite like a HSS bar.

Some Micro 100 bars do have flats on them. I use a bar holder that does not clamp the bar with screws so I can rotate and position the tool however I want so flats don't bother me. Your situation may differ.
 
+ 005 - 000 is a hell of a tolerance.
That means it can be 0.312 at its smallest diameter to 0.317 at its largest. A sharp drill will keep you within that tolerance easily.
 
When anyone makes a radius tool. What do you guys do to try and hone them? Just hit the top and call it a day?
 
Brento, are you referring to a form tool? If so, most have flat tops so you would hone the sides as best you can, then hone the top flat. How well the tools works depends on how well you can get the sides to meet the top.
 
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