On 5/24/2025 6:17 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 help you with a source , but I can say your lathe is probably
a lot more rigid than my old Wards/Logan . I've been playing around with
5/16 and 3/8" shank insert tooling and I find the only time I reach for
a HSS cutter/lantern post is when I can't reach something because of the
size of the QCTP or when I'm using the boring bar tool post . I get
faster smoother and heavier cuts with carbide inserts than I ever did
with the lantern setup . I've got 14 tool holders now for the QC post ...
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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.


On Instagram https://www.instagram.com/reel/DG6TaRwqKR7/?utm_source=ig_web_copy_link&igsh=MzRlODBiNWFlZA==

On YouTube
https://www.youtube.com/shorts/9pJTprbxqxI

After my previous post I bought a couple more tools to hold DCMT inserts including a boring bar.




--
Bob La Londe
CNC Molds N Stuff

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