No, I didn't put the lathe in reverse, except when I meant to anyway.

I bought a new parting tool, and some new parting inserts for it that
were supposedly optimized for high chromium and stainless steels. I
broke a lot of inserts.

I went back to an HSS parting blade, but I used one 3/16 wide (yeah
really) and ground a chip breaker in it. Then I polished by hand with a diamond hone. Turned the lathe speed way down, and cut several pieces
of 1.5in diameter 416 without much issue. It does need a drop (just a
drop) 8-10 times during the cut, but it did the trick without a lot of excitement.

The chip breaker didn't always break the chips, but it did curly them up
nicely when it didn't. I didn't have any wild death metal flying around
in my face.

I'd really like to be able to due this process faster, but atleast some
of my customers are opting for the cheaper aluminum inserts.

Its not a heavy lathe, but its not a toy either. Its got a 14 inch
sling, 3HP motor, and weighs right at 2000lbs. The only thing I thought
of is swapping it out to a 3phase motor so I can change the RPM on the
fly as the diameter decreases. Yeah, I know a real lathe that size would probably weigh twice that.


--
Bob La Londe
CNC Molds N Stuff


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On 2/28/2025 6:37 PM, Bob La Londe wrote:

No, I didn't put the lathe in reverse, except when I meant to anyway.

I bought a new parting tool, and some new parting inserts for it that
were supposedly optimized for high chromium and stainless steels.  I
broke a lot of inserts.

I went back to an HSS parting blade, but I used one 3/16 wide (yeah
really) and ground a chip breaker in it.  Then I polished by hand with a diamond hone.  Turned the lathe speed way down, and cut several pieces
of 1.5in diameter 416 without much issue.  It does need a drop (just a
drop) 8-10 times during the cut, but it did the trick without a lot of excitement.

The chip breaker didn't always break the chips, but it did curly them up nicely when it didn't.  I didn't have any wild death metal flying around
in my face.

I'd really like to be able to due this process faster, but atleast some
of my customers are opting for the cheaper aluminum inserts.

Its not a heavy lathe, but its not a toy either.  Its got a 14 inch
sling, 3HP motor, and weighs right at 2000lbs.  The only thing I thought
of is swapping it out to a 3phase motor so I can change the RPM on the
fly as the diameter decreases. Yeah, I know a real lathe that size would probably weigh twice that.

I'm still using the 73 year old Logan I got almost 25 years ago .
But you're in a different world of machinery requirements . Is there no
way this cutting operation can be done on a bandsaw or a cold saw ?
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On 2/28/2025 5:59 PM, Snag wrote:

On 2/28/2025 6:37 PM, Bob La Londe wrote:

No, I didn't put the lathe in reverse, except when I meant to anyway.

I bought a new parting tool, and some new parting inserts for it that
were supposedly optimized for high chromium and stainless steels.  I
broke a lot of inserts.

I went back to an HSS parting blade, but I used one 3/16 wide (yeah
really) and ground a chip breaker in it.  Then I polished by hand with
a diamond hone.  Turned the lathe speed way down, and cut several
pieces of 1.5in diameter 416 without much issue.  It does need a drop
(just a drop) 8-10 times during the cut, but it did the trick without
a lot of excitement.

The chip breaker didn't always break the chips, but it did curly them
up nicely when it didn't.  I didn't have any wild death metal flying
around in my face.

I'd really like to be able to due this process faster, but atleast
some of my customers are opting for the cheaper aluminum inserts.

Its not a heavy lathe, but its not a toy either.  Its got a 14 inch
sling, 3HP motor, and weighs right at 2000lbs.  The only thing I
thought of is swapping it out to a 3phase motor so I can change the
RPM on the fly as the diameter decreases. Yeah, I know a real lathe
that size would probably weigh twice that.

   I'm still using the 73 year old Logan I got almost 25 years ago .
But you're in a different world of machinery requirements . Is there no
way this cutting operation can be done on a bandsaw or a cold saw ?

I actually was cutting them on a bandsaw up until recently, but then I
needed to chuck up each piece in the lathe twice to face and chamfer.
The little Harbor Freight 4x6-8 cuts all my stainless and alloy, and the
bigger 7x12 cuts all my aluminum. I know that sounds backwards, but I
can get decent SuperCuts HSS bi-metal blades locally at Harbor Freight
for it. I'm using up some carbon steel blades on the bigger saw right
now.

A good quality cold saw could probably make a decent enough cut, but I'd
still need to deburr. The safest way to do that is on the lathe. A
good quality cold saw is also kind of expensive.


--
Bob La Londe
CNC Molds N Stuff

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Sounds like you really worked through the problem! Sometimes, going back to HSS just makes sense, especially with stainless. A well-ground chip breaker and careful honing can do wonders, and it’s great to hear you got clean cuts without drama.

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On 3/5/2025 10:30 PM, Evie Rosie wrote:

Sounds like you really worked through the problem! Sometimes, going back
to HSS just makes sense, especially with stainless. A well-ground chip breaker and careful honing can do wonders, and it’s great to hear you got clean cuts without drama.

Clean with out drama may be a bit of an over statement.


--
Bob La Londe
CNC Molds N Stuff

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On 01/03/2025 00:37, Bob La Londe wrote:

No, I didn't put the lathe in reverse, except when I meant to anyway.

I bought a new parting tool, and some new parting inserts for it that
were supposedly optimized for high chromium and stainless steels.  I
broke a lot of inserts.

I went back to an HSS parting blade, but I used one 3/16 wide (yeah
really) and ground a chip breaker in it.  Then I polished by hand with
a diamond hone.  Turned the lathe speed way down, and cut several
pieces of 1.5in diameter 416 without much issue.  It does need a drop
(just a drop) 8-10 times during the cut, but it did the trick without
a lot of excitement.

The chip breaker didn't always break the chips, but it did curly them
up nicely when it didn't.  I didn't have any wild death metal flying
around in my face.

I'd really like to be able to due this process faster, but atleast
some of my customers are opting for the cheaper aluminum inserts.

Its not a heavy lathe, but its not a toy either.  Its got a 14 inch
sling, 3HP motor, and weighs right at 2000lbs.  The only thing I
thought of is swapping it out to a 3phase motor so I can change the
RPM on the fly as the diameter decreases. Yeah, I know a real lathe
that size would probably weigh twice that.

What brand parting tool and inserts were you using? I've got a Hertel
insert parting blade and inserts, 3mm wide made in Germany, and  have
never broke one but have wore a few out. Lathe is Harrison M300 about
1450lbs. I have experienced issues with cheap parting/grooving tools
where a few inserts crumbled rather than cut, had to change them until I
found a good one that would do the job, I expect that's why they were cheap.

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