What direction should I set up a lathe to turn in?

[PegroProX440]

I am brand new to the CNC lathe, and programming in Esprit as well. Our lathe here is an Okuma LB3000 EXII and it is tooled up so the main spindle turns counterclockwise. So all of the lathe tools are upside down when I look at them from the door. Is there an advantage to this, is this the normal way to do things?

Our machine was set up originally by Gossinger as a turn key deal to produce a specific part. This is how they did it. The guy teaching me how to run the machine is not a lathe guy eather so he doesnt know as well.

 

[Mtndew]

It doesn't matter. How you have it is how the majority of us here in the states do it using RH tooling.
If you want to spin it the other way with the tools right side up, then just buy LH tools.
Legend has it that if you spin it CW with LH tools, it puts the cutting forces into the lathe bed making things more rigid.

 

[boosted]

That is normal. Gravity assist.

Was a head scratcher for me at first too. I learned CNC on toolroom machines that didn't run "upside-down".

 

[Philabuster]

I run left handed tooling as much as I can. I do not like standing on my head to change inserts.

LH tooling also puts the cutting force down into the ways vs trying to lift the turret. This is especially helpful for not so rigid machines.

Threading tools are still right handed of course for 99% of the jobs I run.

 

[FamilyTradition]

I've seen it before as well, its common to run the tools like that. As previously mentioned, if your tools are "upside down", you have the advantage of gravity helping with chip control.

 

[michiganbuck]

RE Philabuster:
Tools direction pushing down towards the greatest support. You don't want the cutting tool direction to lift the work off the machine's greatest support.
Chatter and rapid dulling of Cutters often is the result of lacking ridgity.

 

[DouglasJRizzo]

I am brand new to the CNC lathe, and programming in Esprit as well. Our lathe here is an Okuma LB3000 EXII and it is tooled up so the main spindle turns counterclockwise. So all of the lathe tools are upside down when I look at them from the door. Is there an advantage to this, is this the normal way to do things?

Our machine was set up originally by Gossinger as a turn key deal to produce a specific part. This is how they did it. The guy teaching me how to run the machine is not a lathe guy eather so he doesnt know as well.

I run my Okuma lathe M4 as well with the tools upside down. This way, the cutting forces are going into the machine, rather than away from it. When I need a drill or other RH tool I switch direction as the turret is indexing.

 

[PegroProX440]

Im sure I will have a lot of lathe questions. We are 99% a mill shop but have a few lathe parts all of a sudden.
Thanks for all your feedback so far, it makes sense.

Also on a side note....The speed and clearance of everything is going to take some getting use to.

 

[Philabuster]

Im sure I will have a lot of lathe questions. We are 99% a mill shop but have a few lathe parts all of a sudden.
Thanks for all your feedback so far, it makes sense.

Also on a side note....The speed and clearance of everything is going to take some getting use to.

G50 (max spindle speed clamp) is your friend.

 

[CarbideBob]

Lathes are not what they used to be in layout of slides.
Ideally I would always want to put the cutting tool load into the bigger or more solid side.
Upside down is popular. This maybe a chip and gravity deal.
A stinger up top seems nowhere to go but up, flip the holder and down.
Mean ole mister gravity helps and it it breaks faster and gets it out of the way.

I have never seen a real reason to ever do this but many will have lots of it worked like magic.

 

[SeymourDumore]

I run my Okuma lathe M4 as well with the tools upside down.

'Splain yourself there Lucy!
M4 is counter clockwise, and tool upside down means inserts are down ... I don't see that working out too good!

 

[Mtndew]

'Splain yourself there Lucy!
M4 is counter clockwise, and tool upside down means inserts are down ... I don't see that working out too good!

Maybe he's in Australia.

 

[Johnhudson]

Problem with starting and stopping to reverse spindle is the energy ( And time)it takes specially on a production run. My lathe loves electricity. I prefer to run CCW.

 

[Philabuster]

Problem with starting and stopping to reverse spindle is the energy ( And time)it takes specially on a production run. My lathe loves electricity. I prefer to run CCW.

Valid point. Some lathes like my Mazak are always running in constant surface speed control. As the tool moves away from the chuck, the RPMs slow way down. Reversing the chuck direction is a non issue because the spindle is only turning a few hundred RPM at that time. Time to reverse the spindle is also taken up with the tool change and machine move rapid towards the chuck.

 

[sinha]

'Splain yourself there Lucy!
M4 is counter clockwise, and tool upside down means inserts are down ... I don't see that working out too good!

There are front-type lathes also.

 

[angelw]

There are front-type lathes also.

Hello Sinha,
I think the point is, Douglas's comment doesn't make sense.
Douglas Wrote:
I run my Okuma lathe M4 as well with the tools upside down. This way, the cutting forces are going into the machine, rather than away from it. When I need a drill or other RH tool I switch direction as the turret is indexing.

If the tools were at the back of the machine and Up Side Down, the Spindle would have to run M3 and the tendency would be for the Turret and Carriage to be lifted off the slide ways; so, no directing the cutting forces into the machine there and running the spindle M4 with the tools upside down at the back of the machine is not going to make for very favorable cutting conditions.

If the tools are at the Front of the machine and the Tools Up Side Down, in that case you would run the Spindle M04, but again the cutting forces are contra to what Douglas is suggesting. The tendency would be for the Turret and Carriage to be lifted off the slide ways, so, no directing the cutting forces into the machine there.

Regards,

Bill

 

[sinha]

It is a bit ambiguous when we say that the cutting force is going into the machine or away from it. It is an internal force. If the turret is subjected to an upward force, the spindle is subjected to a downward force of the same magnitude, at the same moment.
I believe the guide ways are designed to take care of the maximum possible cutting forces. The inverted tools have to do mainly with chip disposal.

 

[Philabuster]

It is a bit ambiguous when we say that the cutting force is going into the machine or away from it. It is an internal force. If the turret is subjected to an upward force, the spindle is subjected to a downward force of the same magnitude, at the same moment.
I believe the guide ways are designed to take care of the maximum possible cutting forces. The inverted tools have to do mainly with chip disposal.

There is a difference in cutting forces when hogging off material in a old worn out machine. Cutting with LH tooling produces less chatter on my machine vs RH tooling. Your mileage may vary.

 

[angelw]

It is a bit ambiguous when we say that the cutting force is going into the machine or away from it. It is an internal force. If the turret is subjected to an upward force, the spindle is subjected to a downward force of the same magnitude, at the same moment.
I believe the guide ways are designed to take care of the maximum possible cutting forces. The inverted tools have to do mainly with chip disposal.

If you examine the construction of a typical Box Way lathe, with cutting tools at the rear of the machine with cutting tools upside down, the force being applied to the tools is to lift the two axes off the slide ways. The main restraint are the keeper plates attached to the underside of the slide ways and have a very narrow bearing area compared to the top side of the slideway. Clearly the construction of the machines will cope with the force generated through the cutting action, which is relatively small, but I very much doubt that such machines had their slideways designed in this manner, with upside down orientated tool as the main design criteria.

The keeper plates are normally held on with a number bolts and although able to manage normal cutting forces, in some severe crash situation, I've seen these bolts broken and the underside of the slideway, where the keeper plates interface with the slide, imprinted with the shape of the keeper plate. Conversely, with machines where the tooling is arranged so that the cutting force forces the X and Z carriages down onto their respective slide ways, I've never seen the slideways damaged due to downward force being applied via a crash. There is no question as to which way the cutting forces are better directed.

I believe its more a case born out of convenience that tools are used upside down on machines with tooling at the rear. If "The inverted tools have to do mainly with chip disposal" was the main criteria in determining the orientation of the cutting tool, wouldn't it logically follow that turning tools for lathes with the turret at the front of the machine, use LH tools upside down to also aid in chip disposal? There are plenty of CNC lathes around with front turrets and they handle chips disposal with the tools arranged Top Side Up, quite OK.

Regards,

Bill

 

[sinha]

So, what is better on a rear/front lathe - inverted or non-inverted tools?