Interrupted lathe cuts -- Technique?
 

I'm using manual Sherline lathe and have never been comfortable with turning
down rectangular stock. Now I need to turn to a round 3" of a 2" square
piece of Fortal aluminum. This requires riser blocks all the way around on
the Lathe (to clear the slide but decreasing stiffness) and work holding in
a 3.1" independant 4 jaw chuck with jaws reversed. The grip area for the
chuck in this configuration is quite small which adds to my discomfort (I
will be using a tailstock center). Can someone give me some general or
specific advice on such operations: Is this as hard on the equipment as it
sounds and feels? Best tool to use -- HSS, braised carbide, inserts, normal
rake, etc.? Speed, feed, cut, etc.? General advice or techniques?

Thanks in advance.

Greg

Interrupted lathe cuts -- Technique?
 

Greg G wrote:

I'm using manual Sherline lathe and have never been comfortable with turning
down rectangular stock. Now I need to turn to a round 3" of a 2" square
piece of Fortal aluminum. This requires riser blocks all the way around on
the Lathe (to clear the slide but decreasing stiffness) and work holding in
a 3.1" independant 4 jaw chuck with jaws reversed. The grip area for the
chuck in this configuration is quite small which adds to my discomfort (I
will be using a tailstock center). Can someone give me some general or
specific advice on such operations: Is this as hard on the equipment as it
sounds and feels? Best tool to use -- HSS, braised carbide, inserts, normal
rake, etc.? Speed, feed, cut, etc.? General advice or techniques?

Thanks in advance.

Greg



Bandsaw away most of the waste to start with, maybe you won't need risers ..

GWE

Interrupted lathe cuts -- Technique?
 

"Greg G" wrote in message
news:MQ1Pf.10284$Tf3.7897@dukeread09...
I'm using manual Sherline lathe and have never been comfortable with
turning
down rectangular stock. Now I need to turn to a round 3" of a 2" square
piece of Fortal aluminum. This requires riser blocks all the way around
on
the Lathe (to clear the slide but decreasing stiffness) and work holding
in
a 3.1" independant 4 jaw chuck with jaws reversed. The grip area for the
chuck in this configuration is quite small which adds to my discomfort (I
will be using a tailstock center). Can someone give me some general or
specific advice on such operations: Is this as hard on the equipment as
it
sounds and feels? Best tool to use -- HSS, braised carbide, inserts,
normal
rake, etc.? Speed, feed, cut, etc.? General advice or techniques?

Thanks in advance.

Greg

Grant had a good suggestion----but if you have no saw:

You'll enjoy the best success using HSS, with a generous chip breaker,
forming positive rake. If you're not familiar with what I'm talking about,
contact me on the side and I'll send you a pic or two of tools with chip
breakers to give you an idea. Stay away from carbide on your
machine------especially for something like this.

Interrupted cuts in aluminum aren't an issue, although on your light duty
machine, you could have trouble.
You'll likely be limited to depth of cut and feed rate, but, on a larger
machine, it would be a piece of cake.

By all means, do use the center, which will prevent the part from shifting
in your chuck. Don't expect it to help if you don't use the right
approach. The back side of the piece in question should be faced enough to
form a firm base, making contact appropriately with the chuck body, or the
jaws, then the opposite end faced, then the center applied. If you can't
center drill, face the part after pressing it well in the chuck, then apply
a small piece of stock that has been faced and center drilled, again, to
prevent the part from shifting in your chuck. Make sure the part seats
against something, otherwise you're wasting your time. You have to prevent
the part from starting to move.

Does any of this help? More questions?

Harold

Interrupted lathe cuts -- Technique?
 

Thanks Grant,

My finished diameter (1.97") will be greater than can swing over the slide
so I can't avoid the risers . However, I will keep the suggestion in mind
for future use as I hadn't thought of using my band saw that way -- only
thought of milling.

Greg

"Grant Erwin" wrote in message
...
Greg G wrote:

I'm using manual Sherline lathe and have never been comfortable with
turning
down rectangular stock. Now I need to turn to a round 3" of a 2" square
piece of Fortal aluminum. This requires riser blocks all the way
around on
the Lathe (to clear the slide but decreasing stiffness) and work holding
in
a 3.1" independant 4 jaw chuck with jaws reversed. The grip area for
the
chuck in this configuration is quite small which adds to my discomfort
(I
will be using a tailstock center). Can someone give me some general or
specific advice on such operations: Is this as hard on the equipment as
it
sounds and feels? Best tool to use -- HSS, braised carbide, inserts,
normal
rake, etc.? Speed, feed, cut, etc.? General advice or techniques?

Thanks in advance.

Greg



Bandsaw away most of the waste to start with, maybe you won't need risers
...

GWE

Interrupted lathe cuts -- Technique?
 

Thanks Harold,

Will be sending you an email.

Greg

"Harold and Susan Vordos" wrote in message
...

"Greg G" wrote in message
news:MQ1Pf.10284$Tf3.7897@dukeread09...
I'm using manual Sherline lathe and have never been comfortable with
turning
down rectangular stock. Now I need to turn to a round 3" of a 2" square
piece of Fortal aluminum. This requires riser blocks all the way
around
on
the Lathe (to clear the slide but decreasing stiffness) and work holding
in
a 3.1" independant 4 jaw chuck with jaws reversed. The grip area for
the
chuck in this configuration is quite small which adds to my discomfort
(I
will be using a tailstock center). Can someone give me some general or
specific advice on such operations: Is this as hard on the equipment as
it
sounds and feels? Best tool to use -- HSS, braised carbide, inserts,
normal
rake, etc.? Speed, feed, cut, etc.? General advice or techniques?

Thanks in advance.

Greg

Grant had a good suggestion----but if you have no saw:

You'll enjoy the best success using HSS, with a generous chip breaker,
forming positive rake. If you're not familiar with what I'm talking
about,
contact me on the side and I'll send you a pic or two of tools with chip
breakers to give you an idea. Stay away from carbide on your
machine------especially for something like this.

Interrupted cuts in aluminum aren't an issue, although on your light duty
machine, you could have trouble.
You'll likely be limited to depth of cut and feed rate, but, on a larger
machine, it would be a piece of cake.

By all means, do use the center, which will prevent the part from shifting
in your chuck. Don't expect it to help if you don't use the right
approach. The back side of the piece in question should be faced enough
to
form a firm base, making contact appropriately with the chuck body, or the
jaws, then the opposite end faced, then the center applied. If you
can't
center drill, face the part after pressing it well in the chuck, then
apply
a small piece of stock that has been faced and center drilled, again, to
prevent the part from shifting in your chuck. Make sure the part seats
against something, otherwise you're wasting your time. You have to
prevent
the part from starting to move.

Does any of this help? More questions?

Harold

Interrupted lathe cuts -- Technique?
 

Saw off as much as you can or it will ruin the bearings.
Soon after I bought my 6 inch Craftsman lathe I thought I could take a
Briggs Stratton mower engine and convert it to a 2 stroke. I chopped off
everything 4 stroke and went after it with various cutters, files and
hope.
Totally messed up the bearings but the end result was not bad.
I put new Timkens in there. Good as new.