## Re: [atlas_craftsman] Cutting speeds

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• attached is a spreadsheet to calculate required RPM to get desired SFPM for a selected work piece diameter. I don t know how to pass this on to chase0073 in
Message 1 of 11 , May 31, 2013
attached is a spreadsheet to calculate required RPM to get desired SFPM for a selected work piece diameter.

I don't know how to pass this on to chase0073 in this group

so- if you can please check my math and if it is right - pass it on to chase 0073

if not- contact me so I can correct any mistakes

thanks

Omsrof

On Fri, May 31, 2013 at 9:06 PM, wrote:

Plain cold-rolled steel, about 70 to 100 feet per minute (usually called
"SFM")
Aluminum, double that
Tool steel, half that.

To get the "SFM", work diameter(inches) times 3, divided by 12. multiply
that by rpm. Some people use times 4. The idea is to see how fast the
tool is moving through the workpiece. Works just as well for the cutter
diameter on a mill as for the work diameter on a lathe.

Depth of cut has little to do with it, unless the cut is a large fraction of
the diameter deep. But a deep cut takes more force, and lightweight hobby
machines like Atlas 6" either shouldn't be forced to do that, or should be
backed off on cutting speed to reduce stress.

JT

----- Original Message -----
From: "chase0073" <chase0073@...>
To: <atlas_craftsman@yahoogroups.com>
Sent: Friday, May 31, 2013 4:18 PM
Subject: [atlas_craftsman] Cutting speeds

> So I'm new to the atlas 618 lathe and was curious what is a good speed for
> rough cut and fine cut for aluminum and steel. I am just getting
> comfortable changing the different gears and have never actually threaded
> on a lathe. But I want to learn. I just want to get the basic feed rates
> down then move on. Any help?
>
>
>
> ------------------------------------

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• chase0073, Buy a copy of the Atlas Manual of Lathe Operations (the ones with Craftsman covers are the same as those with Atlas covers). Among many other
Message 2 of 11 , May 31, 2013
chase0073,

Buy a copy of the Atlas Manual of Lathe Operations (the ones with Craftsman covers are the same as those with Atlas covers).  Among many other things, it explains the concept of surface speed and has recommended cutting speed charts for various materials.  Both Atlas and Sears shipped a copy with every lathe that they sold.  Although pretty much any edition will have about the same generic information, the 618 was made from about 1939 to about 1972.  Editions printed after about 1973 won't have any 618 photos in them.  So look for one printed earlier than that.  I don't know why, given that they know that a lot of the older machines are still in service, Clausing never thought to offer reprints of selected older editions.

One thing I will mention as no one else tonight has is that although optimum feed rate and DOC (Depth Of Cut) is independant of workpiece diameter, spindle RPM is not.  If you calculate or look up the approximate recommended RPM for say mild steel of 1" diameter but you part is 1/2" diameter, you need to double the RPM as work piece surface speed is directly proportional to diameter.  Double the diameter for a given RPM and you double the surface speed.

Also, in most materials and with most cutters, the optimum surface feet per minute (SFM) is the same or about the same for roughing and finish cuts.  What you usually vary is DOC and feed.

Robert D.

In a message dated 5/31/2013 4:18:11 PM Central Daylight Time, chase0073@... writes:
So I'm new to the atlas 618 lathe and was curious what is a good speed for rough cut and fine cut for aluminum and steel. I am just getting comfortable changing the different gears and have never actually threaded on a lathe. But I want to learn. I just want to get the basic feed rates down then move on. Any help?

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480
• Wow thanks for the info....gonna have to go back to math class to understand it all(lol). I do have the atlas manual(actually 2) and did go over all. But going
Message 3 of 11 , Jun 1 7:47 AM
Wow thanks for the info....gonna have to go back to math class to understand it all(lol). I do have the atlas manual(actually 2) and did go over all. But going back to it this morning I somewhat figured it out. I didn't know what the .0087, .015, .0035, etc were used for. Now the only thing I'm not seeing is where those gears should be placed on the gear stud assembly?

Sent from my iPhone

On Jun 1, 2013, at 1:19 AM, wa5cab@... wrote:

chase0073,

Buy a copy of the Atlas Manual of Lathe Operations (the ones with Craftsman covers are the same as those with Atlas covers).  Among many other things, it explains the concept of surface speed and has recommended cutting speed charts for various materials.  Both Atlas and Sears shipped a copy with every lathe that they sold.  Although pretty much any edition will have about the same generic information, the 618 was made from about 1939 to about 1972.  Editions printed after about 1973 won't have any 618 photos in them.  So look for one printed earlier than that.  I don't know why, given that they know that a lot of the older machines are still in service, Clausing never thought to offer reprints of selected older editions.

One thing I will mention as no one else tonight has is that although optimum feed rate and DOC (Depth Of Cut) is independant of workpiece diameter, spindle RPM is not.  If you calculate or look up the approximate recommended RPM for say mild steel of 1" diameter but you part is 1/2" diameter, you need to double the RPM as work piece surface speed is directly proportional to diameter.  Double the diameter for a given RPM and you double the surface speed.

Also, in most materials and with most cutters, the optimum surface feet per minute (SFM) is the same or about the same for roughing and finish cuts.  What you usually vary is DOC and feed.

Robert D.

In a message dated 5/31/2013 4:18:11 PM Central Daylight Time, chase0073@... writes:

So I'm new to the atlas 618 lathe and was curious what is a good speed for rough cut and fine cut for aluminum and steel. I am just getting comfortable changing the different gears and have never actually threaded on a lathe. But I want to learn. I just want to get the basic feed rates down then move on. Any help?

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480

• Look for a setup chart n the group file. I have one for a 10F. if you cant find it i am sure Robert will help   GP ________________________________ From:
Message 4 of 11 , Jun 1 7:56 AM
Look for a setup chart n the group file. I have one for a 10F. if you cant find it i am sure Robert will help

GP

From: Shawn Chase <chase0073@...>
To: "atlas_craftsman@yahoogroups.com" <atlas_craftsman@yahoogroups.com>
Sent: Sat, June 1, 2013 10:49:45 AM
Subject: Re: [atlas_craftsman] Cutting speeds

Wow thanks for the info....gonna have to go back to math class to understand it all(lol). I do have the atlas manual(actually 2) and did go over all. But going back to it this morning I somewhat figured it out. I didn't know what the .0087, .015, .0035, etc were used for. Now the only thing I'm not seeing is where those gears should be placed on the gear stud assembly?

Sent from my iPhone

On Jun 1, 2013, at 1:19 AM, wa5cab@... wrote:

chase0073,

Buy a copy of the Atlas Manual of Lathe Operations (the ones with Craftsman covers are the same as those with Atlas covers).  Among many other things, it explains the concept of surface speed and has recommended cutting speed charts for various materials.  Both Atlas and Sears shipped a copy with every lathe that they sold.  Although pretty much any edition will have about the same generic information, the 618 was made from about 1939 to about 1972.  Editions printed after about 1973 won't have any 618 photos in them.  So look for one printed earlier than that.  I don't know why, given that they know that a lot of the older machines are still in service, Clausing never thought to offer reprints of selected older editions.

One thing I will mention as no one else tonight has is that although optimum feed rate and DOC (Depth Of Cut) is independant of workpiece diameter, spindle RPM is not.  If you calculate or look up the approximate recommended RPM for say mild steel of 1" diameter but you part is 1/2" diameter, you need to double the RPM as work piece surface speed is directly proportional to diameter.  Double the diameter for a given RPM and you double the surface speed.

Also, in most materials and with most cutters, the optimum surface feet per minute (SFM) is the same or about the same for roughing and finish cuts.  What you usually vary is DOC and feed.

Robert D.

In a message dated 5/31/2013 4:18:11 PM Central Daylight Time, chase0073@... writes:

So I'm new to the atlas 618 lathe and was curious what is a good speed for rough cut and fine cut for aluminum and steel. I am just getting comfortable changing the different gears and have never actually threaded on a lathe. But I want to learn. I just want to get the basic feed rates down then move on. Any help?

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480

• chase0073, If you log in to the A_C group on Yahoo and go to Files and then to Manuals, Atlas and Atlas-Craftsman Lathes, you will find a manual on the 612 and
Message 5 of 11 , Jun 1 8:26 AM
chase0073,

If you log in to the A_C group on Yahoo and go to Files and then to Manuals, Atlas and Atlas-Craftsman Lathes, you will find a manual on the 612 and 618.  Among other things, it contains a spindle speed chart (twice,  actually - I need to fix that), an illustrated parts list and at the back a Threading Chart.  The latter has drawings showing the approximate location of all of the gears that normally get changed for the various feeds.

Generally, finish cuts are taken with the smallest feed available.  Roughing cuts can be taken with a coarser feed to save time.  But they don't actually have to be, especially if you don't have much metal to remove.  An additional pass or three may take less time than changing the gears.

Robert D.

In a message dated 6/1/2013 9:47:58 AM Central Daylight Time, chase0073@... writes:
Wow thanks for the info....gonna have to go back to math class to understand it all(lol). I do have the atlas manual(actually 2) and did go over all. But going back to it this morning I somewhat figured it out. I didn't know what the .0087, .015, .0035, etc were used for. Now the only thing I'm not seeing is where those gears should be placed on the gear stud assembly?

Sent from my iPhone

On Jun 1, 2013, at 1:19 AM, wa5cab@... wrote:

chase0073,

Buy a copy of the Atlas Manual of Lathe Operations (the ones with Craftsman covers are the same as those with Atlas covers).  Among many other things, it explains the concept of surface speed and has recommended cutting speed charts for various materials.  Both Atlas and Sears shipped a copy with every lathe that they sold.  Although pretty much any edition will have about the same generic information, the 618 was made from about 1939 to about 1972.  Editions printed after about 1973 won't have any 618 photos in them.  So look for one printed earlier than that.  I don't know why, given that they know that a lot of the older machines are still in service, Clausing never thought to offer reprints of selected older editions.

One thing I will mention as no one else tonight has is that although optimum feed rate and DOC (Depth Of Cut) is independant of workpiece diameter, spindle RPM is not.  If you calculate or look up the approximate recommended RPM for say mild steel of 1" diameter but you part is 1/2" diameter, you need to double the RPM as work piece surface speed is directly proportional to diameter.  Double the diameter for a given RPM and you double the surface speed.

Also, in most materials and with most cutters, the optimum surface feet per minute (SFM) is the same or about the same for roughing and finish cuts.  What you usually vary is DOC and feed.

Robert D.

In a message dated 5/31/2013 4:18:11 PM Central Daylight Time, chase0073@... writes:

So I'm new to the atlas 618 lathe and was curious what is a good speed for rough cut and fine cut for aluminum and steel. I am just getting comfortable changing the different gears and have never actually threaded on a lathe. But I want to learn. I just want to get the basic feed rates down then move on. Any help?

Robert &Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480
• So I didn t actually notice the thread chart actually had the other feed rates on it also. Great now I got a much better understanding. Time for me to go makes
Message 6 of 11 , Jun 1 8:52 AM
So I didn't actually notice the thread chart actually had the other feed rates on it also. Great now I got a much better understanding. Time for me to go makes some chips!! Oh one more question...What is the best cleaner to remove the old wax and dried up lube on the gears?

--- In atlas_craftsman@yahoogroups.com, wa5cab@... wrote:
>
> chase0073,
>
> If you log in to the A_C group on Yahoo and go to Files and then to
> Manuals, Atlas and Atlas-Craftsman Lathes, you will find a manual on the 612 and
> 618. Among other things, it contains a spindle speed chart (twice, actually
> - I need to fix that), an illustrated parts list and at the back a Threading
> Chart. The latter has drawings showing the approximate location of all of
> the gears that normally get changed for the various feeds.
>
> Generally, finish cuts are taken with the smallest feed available.
> Roughing cuts can be taken with a coarser feed to save time. But they don't
> actually have to be, especially if you don't have much metal to remove. An
> additional pass or three may take less time than changing the gears.
>
> Robert D.
>
> In a message dated 6/1/2013 9:47:58 AM Central Daylight Time,
> chase0073@... writes:
> > Wow thanks for the info....gonna have to go back to math class to
> > understand it all(lol). I do have the atlas manual(actually 2) and did go over
> > all. But going back to it this morning I somewhat figured it out. I didn't
> > know what the .0087, .015, .0035, etc were used for. Now the only thing I'm
> > not seeing is where those gears should be placed on the gear stud assembly?
> >
> > Sent from my iPhone
> >
> > On Jun 1, 2013, at 1:19 AM, wa5cab@... wrote:
> >
> >
> > >> chase0073,
> >>
> >> Buy a copy of the Atlas Manual of Lathe Operations (the ones with
> >> Craftsman covers are the same as those with Atlas covers). Among many other
> >> things, it explains the concept of surface speed and has recommended cutting
> >> speed charts for various materials. Both Atlas and Sears shipped a copy
> >> with every lathe that they sold. Although pretty much any edition will have
> >> about 1972. Editions printed after about 1973 won't have any 618 photos in
> >> them. So look for one printed earlier than that. I don't know why,
> >> given that they know that a lot of the older machines are still in service,
> >> Clausing never thought to offer reprints of selected older editions.
> >>
> >> One thing I will mention as no one else tonight has is that although
> >> optimum feed rate and DOC (Depth Of Cut) is independant of workpiece diameter,
> >> spindle RPM is not. If you calculate or look up the approximate
> >> recommended RPM for say mild steel of 1" diameter but you part is 1/2" diameter,
> >> you need to double the RPM as work piece surface speed is directly
> >> proportional to diameter. Double the diameter for a given RPM and you double the
> >> surface speed.
> >>
> >> Also, in most materials and with most cutters, the optimum surface feet
> >> per minute (SFM) is the same or about the same for roughing and finish
> >> cuts. What you usually vary is DOC and feed.
> >>
> >> Robert D.
> >>
> >> In a message dated 5/31/2013 4:18:11 PM Central Daylight Time,
> >> chase0073@... writes:
> >>
> >>
> >> >>> So I'm new to the atlas 618 lathe and was curious what is a good
> >>> speed for rough cut and fine cut for aluminum and steel. I am just getting
> >>> comfortable changing the different gears and have never actually threaded
> >>> on a lathe. But I want to learn. I just want to get the basic feed rates
> >>> down then move on. Any help?
> >>>
> >>
> >>
> >> Robert &Susan Downs - Houston
> >> wa5cab dot com (Web Store)
> >> MVPA 9480
> >>
> >>
> >>
> >
>
> Robert & Susan Downs - Houston
> wa5cab dot com (Web Store)
> MVPA 9480
>
• what the .0087, .015, .0035, etc were used for. Now the FWIW ..recommend setting feed gears for ..0035 fro normal work AND feeding the carriage manually
Message 7 of 11 , Jun 1 10:18 AM
what the .0087, .015, .0035, etc were used for. Now the

FWIW ..recommend  setting feed  gears for ..0035 fro  normal  work  AND feeding the  carriage  manually for  short  length of  cuts ....atlas crftsmn &south  bend 9 "C" lathes, light , 10  & some 10 in   Logans  use the 1/2 nuts  &  lead screw  for feed as  well as  threads ...by manually  feeding , you save  the  1/2 nuts  & lead screw  wear   , retaining   them  for  more  accurate  threading ....AND by  manually  feeding the  carriage , you will get a  feel  of  what  the  machine can  do &  where it "likes  to  be...you also go fast or  slo dependant on  need......finish   quality  is  more dependant on tool bit  grind / setting   than  feed ......i can  get  a  smooth  non ridged  finish at .007( slowest  belt  feed) feed on  my antique 14 in  Reed  lathe by bit &  tool  selection ......the  ridges  left  by  a  pointed finish  tool are  simply VERY  fine  threads ...
FWIW ..in  my  experience .a 1/32 flat point  gives  a  better  finish  than a  rounded  point &  a  shear grind bit , taking out  the  ridges  on an  angle   even better...( w/ a  finish  cut of  say 5 thou depth , a small rounded  point  does not penetrate   enuf to allow the  width to take out  the  feed marks , & a  very  broad  round point   induces  chatter ...)again  recommend machine  tool  operation by  burghardt vol1on  abe  books  or  ebay  shud be around \$10 ...almost  50 yrs  later , i still refer back at  times

best  wishes......
doc
-----Original Message-----
From: Shawn Chase <chase0073@...>
To: atlas_craftsman <atlas_craftsman@yahoogroups.com>
Sent: Sat, Jun 1, 2013 11:32 am
Subject: Re: [atlas_craftsman] Cutting speeds

Wow thanks for the info....gonna have to go back to math class to understand it all(lol). I do have the atlas manual(actually 2) and did go over all. But going back to it this morning I somewhat figured it out. I didn't know what the .0087, .015, .0035, etc were used for. Now the only thing I'm not seeing is where those gears should be placed on the gear stud assembly?

Sent from my iPhone

On Jun 1, 2013, at 1:19 AM, wa5cab@... wrote:

chase0073,

Buy a copy of the Atlas Manual of Lathe Operations (the ones with Craftsman covers are the same as those with Atlas covers).  Among many other things, it explains the concept of surface speed and has recommended cutting speed charts for various materials.  Both Atlas and Sears shipped a copy with every lathe that they sold.  Although pretty much any edition will have about the same generic information, the 618 was made from about 1939 to about 1972.  Editions printed after about 1973 won't have any 618 photos in them.  So look for one printed earlier than that.  I don't know why, given that they know that a lot of the older machines are still in service, Clausing never thought to offer reprints of selected older editions.

One thing I will mention as no one else tonight has is that although optimum feed rate and DOC (Depth Of Cut) is independant of workpiece diameter, spindle RPM is not.  If you calculate or look up the approximate recommended RPM for say mild steel of 1" diameter but you part is 1/2" diameter, you need to double the RPM as work piece surface speed is directly proportional to diameter.  Double the diameter for a given RPM and you double the surface speed.

Also, in most materials and with most cutters, the optimum surface feet per minute (SFM) is the same or about the same for roughing and finish cuts.  What you usually vary is DOC and feed.

Robert D.

In a message dated 5/31/2013 4:18:11 PM Central Daylight Time, chase0073@... writes:
So I'm new to the atlas 618 lathe and was curious what is a good speed for rough cut and fine cut for aluminum and steel. I am just getting comfortable changing the different gears and have never actually threaded on a lathe. But I want to learn. I just want to get the basic feed rates down then move on. Any help?

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480
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