Re: Carbide on antique lathe again

On 5/24/2025 4:17 AM, Jim Wilkins wrote:

Things have changed since I asked this, I found a Baldor-type carbide grinder and a diamond wheel for it and tightened up the worst wear on my SB Heavy 10 by surface grinding the compound base. I acquired a GTN-2 cutoff holder and a very stiff boring bar for 1/4" IC triangular inserts. Both cut the rock drill rod to a smooth finish and haven't (yet) chipped. Though annealed the steel is still hard enough to quickly dull HSS if not in back gear.
 This says a solution is possible.
https://www.thegallos.com/carbide.htm
https://www.thegallos.com/response.htm
 Can anyone suggest specific inserts in those sizes they know to work well on a slow worn lathe, preferably 'affordable' ones from a dealer that sells them individually like LMS? The ones I bought from an Enco store the first time I tried carbide soon chipped. They were C5 and C6 grade, maybe I should have tried C2.
 

I can't promise the same results, but I have had very good luck with small stainless/alloy geometry DCMT inserts.  Lots of hobby lathe guys use them.  I think because of their small total size the chip breakers are forced to be smaller allowing them to work on lathes that have to take a smaller cut.  I can't make chips that go CLANK when they hit the floor, but they are better than you might think.
I have NOT found an insert I like for parting.  I am still hand sharpening and hand cutting the chip breaker in M42 HSS parting blades at reduced speed.
Some time ago (not that long) I posted here about this.
Here is a quick video of facing, rough turning, and parting with a middle weight (2000lbs) mediocre rigidity 2hp lathe.
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After my previous post I bought a couple more tools to hold DCMT inserts including a boring bar.
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Bob La Londe
CNC Molds N Stuff
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