OK guys,

I'm going to take the risk. Absolute stone newbie here...

Recently got access to a lathe. I need to turn some 6061-T6 aluminum
pipe from 2.4" OD down to 2.128" OD. How deep a cut can I take in a pass?
Carbide or HSS tool? Lubed or dry? Rotational speed? Feed rate?

I've practiced on a spare piece, but have had zero luck, or
instruction, on the speed/feed/depth-of-cut thing. It doesn't have to win
any beauty contests, but I sure wouldn't mind if it came out looking decent.
I'll also need to cut some plugs to fit the ID from some solid bar. That has
to come out smooth and pretty. It will have an o-ring groove, and must be
removable with ease.

The only thing I've ever cut on a lathe was some graphite, and that
stuff is so soft I could cut it with a butter knife. Wasn't a challenge. But
this aluminum is another story.

Thanks for any and all help,

James
remove the obvious from email addy

James L. Marino wrote:

OK guys,

I'm going to take the risk. Absolute stone newbie here...

Recently got access to a lathe. I need to turn some 6061-T6 aluminum
pipe from 2.4" OD down to 2.128" OD. How deep a cut can I take in a pass?
Carbide or HSS tool? Lubed or dry? Rotational speed? Feed rate?

I've practiced on a spare piece, but have had zero luck, or
instruction, on the speed/feed/depth-of-cut thing. It doesn't have to win
any beauty contests, but I sure wouldn't mind if it came out looking decent.
I'll also need to cut some plugs to fit the ID from some solid bar. That has
to come out smooth and pretty. It will have an o-ring groove, and must be
removable with ease.

The only thing I've ever cut on a lathe was some graphite, and that
stuff is so soft I could cut it with a butter knife. Wasn't a challenge. But
this aluminum is another story.

Thanks for any and all help,

James
remove the obvious from email addy

I'm not exactly a pro, but:

You can take as deep a cut as your lathe can handle. If you have
coolant running onto it, and it's a nice rigid lathe, and your pipe is
firmly mounted then you could almost do it in one whack. But the only
reason not to take light cuts is speed.

When you're almost there you'll want to take light cuts. You'll also
want to use a tool with a more rounded tip and feed slowly -- this will
reduce the amount that the tool marks stand out. If you use an 80-mil
diameter tip and feed dead slow then you will almost have a mirror finish.

At least use oil -- I don't care about speed, so I go no more than 1/2
the "usual" recommended speed and I just use a bit of motor oil rather
than fancy coolant.

It would be nice if there were shop manuals for the amateur machinist --
all the manuals and handbooks that I can find assume that you'll be in a
shop with an expert there to help you, so they leave out the really
essential stuff. I only get time on the lathe at night when my kids are
asleep so I'm pretty much fully self-taught.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

On Mon, 29 Nov 2004 20:05:26 -0800, Tim Wescott
wrote:

James L. Marino wrote:

OK guys,

I'm going to take the risk. Absolute stone newbie here...

Recently got access to a lathe. I need to turn some 6061-T6 aluminum
pipe from 2.4" OD down to 2.128" OD. How deep a cut can I take in a pass?
Carbide or HSS tool? Lubed or dry? Rotational speed? Feed rate?

I've practiced on a spare piece, but have had zero luck, or
instruction, on the speed/feed/depth-of-cut thing. It doesn't have to win
any beauty contests, but I sure wouldn't mind if it came out looking decent.
I'll also need to cut some plugs to fit the ID from some solid bar. That has
to come out smooth and pretty. It will have an o-ring groove, and must be
removable with ease.

The only thing I've ever cut on a lathe was some graphite, and that
stuff is so soft I could cut it with a butter knife. Wasn't a challenge. But
this aluminum is another story.

Thanks for any and all help,

James
remove the obvious from email addy

I'm not exactly a pro, but:

You can take as deep a cut as your lathe can handle. If you have
coolant running onto it, and it's a nice rigid lathe, and your pipe is
firmly mounted then you could almost do it in one whack. But the only
reason not to take light cuts is speed.

When you're almost there you'll want to take light cuts. You'll also
want to use a tool with a more rounded tip and feed slowly -- this will
reduce the amount that the tool marks stand out. If you use an 80-mil
diameter tip and feed dead slow then you will almost have a mirror finish.

At least use oil -- I don't care about speed, so I go no more than 1/2
the "usual" recommended speed and I just use a bit of motor oil rather
than fancy coolant.

Kerosene or WD-40 works well with aluminium

It would be nice if there were shop manuals for the amateur machinist --
all the manuals and handbooks that I can find assume that you'll be in a
shop with an expert there to help you, so they leave out the really
essential stuff. I only get time on the lathe at night when my kids are
asleep so I'm pretty much fully self-taught.
"How to run a lathe" from South Bend is well worth ten times what I
paid for my desk copy - $0.25. I think Atlas also had a similar book.
Gerry :-)}
London, Canada

Gerald Miller wrote:
On Mon, 29 Nov 2004 20:05:26 -0800, Tim Wescott
wrote:


James L. Marino wrote:


OK guys,

I'm going to take the risk. Absolute stone newbie here...

Recently got access to a lathe. I need to turn some 6061-T6 aluminum
pipe from 2.4" OD down to 2.128" OD. How deep a cut can I take in a pass?
Carbide or HSS tool? Lubed or dry? Rotational speed? Feed rate?

I've practiced on a spare piece, but have had zero luck, or
instruction, on the speed/feed/depth-of-cut thing. It doesn't have to win
any beauty contests, but I sure wouldn't mind if it came out looking decent.
I'll also need to cut some plugs to fit the ID from some solid bar. That has
to come out smooth and pretty. It will have an o-ring groove, and must be
removable with ease.

The only thing I've ever cut on a lathe was some graphite, and that
stuff is so soft I could cut it with a butter knife. Wasn't a challenge. But
this aluminum is another story.

Thanks for any and all help,

James
remove the obvious from email addy

I'm not exactly a pro, but:

You can take as deep a cut as your lathe can handle. If you have
coolant running onto it, and it's a nice rigid lathe, and your pipe is
firmly mounted then you could almost do it in one whack. But the only
reason not to take light cuts is speed.

When you're almost there you'll want to take light cuts. You'll also
want to use a tool with a more rounded tip and feed slowly -- this will
reduce the amount that the tool marks stand out. If you use an 80-mil
diameter tip and feed dead slow then you will almost have a mirror finish.

At least use oil -- I don't care about speed, so I go no more than 1/2
the "usual" recommended speed and I just use a bit of motor oil rather
than fancy coolant.


Kerosene or WD-40 works well with aluminium


It would be nice if there were shop manuals for the amateur machinist --
all the manuals and handbooks that I can find assume that you'll be in a
shop with an expert there to help you, so they leave out the really
essential stuff. I only get time on the lathe at night when my kids are
asleep so I'm pretty much fully self-taught.

"How to run a lathe" from South Bend is well worth ten times what I
paid for my desk copy - $0.25. I think Atlas also had a similar book.
Gerry :-)}
London, Canada

Not only does the local used bookstore have it, but they _also_ had a
1948 ARRL handbook -- I've been looking for one of the "war years"
handbooks to replace my worn-out 1945 copy, this at least gets me closer.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

"James L. Marino" wrote in
om:

OK guys,

I'm going to take the risk. Absolute stone newbie here...

Recently got access to a lathe. I need to turn some 6061-T6
aluminum
pipe from 2.4" OD down to 2.128" OD. How deep a cut can I take in a
pass? Carbide or HSS tool? Lubed or dry? Rotational speed? Feed rate?

I've practiced on a spare piece, but have had zero luck, or
instruction, on the speed/feed/depth-of-cut thing. It doesn't have to
win any beauty contests, but I sure wouldn't mind if it came out
looking decent. I'll also need to cut some plugs to fit the ID from
some solid bar. That has to come out smooth and pretty. It will have
an o-ring groove, and must be removable with ease.

The only thing I've ever cut on a lathe was some graphite, and
that
stuff is so soft I could cut it with a butter knife. Wasn't a
challenge. But this aluminum is another story.

Thanks for any and all help,

James
remove the obvious from email addy






Tooling preference:
1. PCD (polycrystalline diamond) - if available, by and far the best
choice for aluminum.
2. Polished carbide, with ~8-12° backrake, generous clearance angles.
3. Polished HSS, also with the backrake and clearance angles.

Speeds in order with tools above:
1. Maximum RPM of the lathe.
2. 60% of Max RPM
3. 40% of Max RPM

Feeds:
1. Up to ~0.03"/rev (depending on ridgity)
2. Up to ~0.02"/rev (depending on ridgity)
3. Up to ~0.01"/rev (depending on ridgity)

Depth of cut:
1. Take all but 0.005 in one pass (provided the lathe has the horsepower,
and you have a good setup and that that depth does not exceed the length
of the PCD.
2. Would probably take that in 3 rough passes, with a 4th finish pass
using carbide.
3. Same as carbide

Use coolant, plenty of it. You must remove all the heat you can from the
cutting process. Diamond tooling will not build up aluminum at the
cutting edge, carbide and HSS will.



--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

Remove sp to reply via email

good advice on the other posts, for the background books pick up some of
these oldies but goodies: (well worth the small $$)
http://www.lindsaybks.com/bks/lathebk/index.html

James L. Marino wrote:

OK guys,

I'm going to take the risk. Absolute stone newbie here...

Recently got access to a lathe. I need to turn some 6061-T6 aluminum
pipe from 2.4" OD down to 2.128" OD. How deep a cut can I take in a pass?
Carbide or HSS tool? Lubed or dry? Rotational speed? Feed rate?

I've practiced on a spare piece, but have had zero luck, or
instruction, on the speed/feed/depth-of-cut thing. It doesn't have to win
any beauty contests, but I sure wouldn't mind if it came out looking decent.
I'll also need to cut some plugs to fit the ID from some solid bar. That has
to come out smooth and pretty. It will have an o-ring groove, and must be
removable with ease.

The only thing I've ever cut on a lathe was some graphite, and that
stuff is so soft I could cut it with a butter knife. Wasn't a challenge. But
this aluminum is another story.

Thanks for any and all help,

James
remove the obvious from email addy

Thank you to all that responded. I appreciate the help, and hope to
become a contributing member of this forum in the future.

James

"James L. Marino" wrote in message
om...
OK guys,

I'm going to take the risk. Absolute stone newbie here...

Recently got access to a lathe. I need to turn some 6061-T6
aluminum
pipe from 2.4" OD down to 2.128" OD. How deep a cut can I take in a pass?
Carbide or HSS tool? Lubed or dry? Rotational speed? Feed rate?

I've practiced on a spare piece, but have had zero luck, or
instruction, on the speed/feed/depth-of-cut thing. It doesn't have to win
any beauty contests, but I sure wouldn't mind if it came out looking
decent.
I'll also need to cut some plugs to fit the ID from some solid bar. That
has
to come out smooth and pretty. It will have an o-ring groove, and must be
removable with ease.

The only thing I've ever cut on a lathe was some graphite, and
that
stuff is so soft I could cut it with a butter knife. Wasn't a challenge.
But
this aluminum is another story.

Thanks for any and all help,

James
remove the obvious from email addy

"James L. Marino" wrote in message . com...
OK guys,

I'm going to take the risk. Absolute stone newbie here...

Recently got access to a lathe. I need to turn some 6061-T6 aluminum
pipe from 2.4" OD down to 2.128" OD. How deep a cut can I take in a pass?
Carbide or HSS tool? Lubed or dry? Rotational speed? Feed rate?

I've practiced on a spare piece, but have had zero luck, or
instruction, on the speed/feed/depth-of-cut thing. It doesn't have to win
any beauty contests, but I sure wouldn't mind if it came out looking decent.
I'll also need to cut some plugs to fit the ID from some solid bar. That has
to come out smooth and pretty. It will have an o-ring groove, and must be
removable with ease.

The only thing I've ever cut on a lathe was some graphite, and that
stuff is so soft I could cut it with a butter knife. Wasn't a challenge. But
this aluminum is another story.

Thanks for any and all help,

James
remove the obvious from email addy

We turn 6061-T6 six days a week, two shifts a day.
3.25 dia. Roughing depth of cut .150, .02 in/rev, 1800 rpm. Finish cut
of .02 at 3000 rpm and feed .0025. Waterbased coolant.