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

So, what is better on a rear/front lathe - inverted or non-inverted tools?
In terms of cutting forces, for machines with the Turret at the rear and typical OD Turning and B/Bars machining towards the chuck, Left Hand Tools with the Insert facing up, Spindle running M04. For a machine with the Turret at the front, Right Hand Turning and B/Bars with the Insert facing up, Spindle running M03.

Regards,

Bill
 
Unless your cutting force (we'll ignore moment, though that is probably more important) is greater than the weight of the turret assembly, you're not "lifting" the turret from the ways.

For my small to tiny parts in copper and stainless, the cutting forces are never much, but chip control is a big issue. We run M3 and the tools upside down.
 
Hope all are well, haven't been hanging around much lately. Far too much going on in life lately.

Everyone has great points here. My opinion certainly doesn't matter. But IMHO, the direction of tools you select is mainly a personal preference. As mentioned there are case where one way does better than the other, but generally it doesn't make a difference. Most people don't know how or aren't willing to push their tooling and machines to their full potential. No, using every little bit of horsepower and thrust on a lathe to push a drill or turning tool is not "beating" on a machine. If you are using it in a way that could cause mechanical issues, such as lifting the slide off the ways, then yes this could be considered beating on it.

The only time that hand of tools really starts to become important is when you have a multistream environment, such as a multi-turret machine. Not properly setting up hand of tool, and generally only using RH tools, will cause lots of spindle reversals and will severly limit the opportunity to multitask thus lengthen the cycle times. Why bias toward, RH. So you can drill and turn at the same time. Simple as that. But if you think about it. One turret will be lifting, the other will be pushing. You can't "win" in these cases.
 
Based on the ongoing discussion, I understand that
1. if the tool is upside up, this will cause less damage to the slide system in case of accidents (including accidental heavy cuts), because the impact direction would be towards the slide.
2. If the tool is upside down, chip control is better. In the other type of arrangement, it may scatter all over the enclosure.
 
Hope all are well, haven't been hanging around much lately. Far too much going on in life lately.

Everyone has great points here. My opinion certainly doesn't matter. But IMHO, the direction of tools you select is mainly a personal preference. As mentioned there are case where one way does better than the other, but generally it doesn't make a difference. Most people don't know how or aren't willing to push their tooling and machines to their full potential. No, using every little bit of horsepower and thrust on a lathe to push a drill or turning tool is not "beating" on a machine. If you are using it in a way that could cause mechanical issues, such as lifting the slide off the ways, then yes this could be considered beating on it.

The only time that hand of tools really starts to become important is when you have a multistream environment, such as a multi-turret machine. Not properly setting up hand of tool, and generally only using RH tools, will cause lots of spindle reversals and will severly limit the opportunity to multitask thus lengthen the cycle times. Why bias toward, RH. So you can drill and turn at the same time. Simple as that. But if you think about it. One turret will be lifting, the other will be pushing. You can't "win" in these cases.
Good points!
 
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.
How far do you move away from your part before turret index, I keep mine pretty close.
 
'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!
Spindle runs in M4, tools have the inserts facing "up" so the machine is cutting "down" into the tool and into the machine, not up and away from it.
 








 
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