Pic of Carbide Cuts on Homeshop Lathe...

I'll really defer this one to Bill because he was just working on pieces about that size. I have limited experience because the propeller shafts I do are mainly 1 to 1-1/4". They must have a near polished finish because there are 2-3 synthetic material grease and oil seals on them. If the finish is rough, it eats those seals in no time.

I will guess that smaller diameters will need RPMs faster than the machine can produce. You can indeed cut stainless (or any material) with lower than recommended RPMs with carbide but the gloss finish won't happen.

Bill... Help!



woodtickgreg said:
Hey thanks for the reply Ray. Most of what I will be doing is turning 1/2" and 3/8" 304 square stainless to round. I have wondered if high speed steel would be better or carbide on my old south bend. I know what you mean "by ear". I am doing some work with some 315 stainless and it polishes and buffs up beautifully, like a mirror.
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I so wish the questions would be asked out here and not in a PM. OK --- The tool grind is nothing spectacular. Here are the pics of one I just ground. I rough with this one, to finish cut I do not break the sharp corner on the cutting edge. I have used this grind geometry for many years with no real problems. In the first pic you are looking at the top of the tool. ------ "Billy G"

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Ray C said:
I'm so glad Bill showed that... It's the perfect opportunity to show where HSS is superior... Can anybody take a guess why? (hint, look at the shoulders).
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And I will need a sharp shoulder like that, so HSS may be the way to go for me. And also because until it is round it will be an interrupted cut.
 
Bill is giving another hint with those pictures.


PS: Nice grind. I gotta try to make one some time.
 
HSS works better with our older machines because they can't get up to the required speeds for carbide. If that ain't it, ya got me....but hey, I haven't even made chips yet. :p
 
I run the spindle speed for rough at 800 RPM. Feed rate I guess LOL. To finish cut I bring the spindle to 1200 RPM and only take light cuts. It cleans up nicely with .005 in two cuts. You see the results in the other pics. For interrupted cuts break that sharp corner on the nose, it won't last long if you don't. ------ "Billy G"
 
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Splat said:
HSS works better with our older machines because they can't get up to the required speeds for carbide. If that ain't it, ya got me....but hey, I haven't even made chips yet. :p
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This is only partially true. HSS works better because you can control the geometry. With carbide you get what you get unless you have the means to grind your own. BTW, my lathe is only 15 years old, that makes it new. I still prefer HSS over carbide in all but a few cases. My lathe spindle can top 2000 RPM, that's scary :lmao:------ "Billy G"
 
That's pretty much the answer... With HSS, you can get a sharp, pointy bit and cut sharp corners. My experience with carbide is somewhat limited but I've never seen it with a very pointy tip. It would probably fracture easily.

woodtickgreg said:
And I will need a sharp shoulder like that, so HSS may be the way to go for me. And also because until it is round it will be an interrupted cut.
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Two sharp edges, one HSS one Carbide. If both hit a little hard, both will lose that sharp edge. Carbide will probably go sooner from chipping but that is not the concern here. The HSS cutter can be re-edged in a few seconds. Carbide will probably need replacing. ------ "Billy G"
 
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