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Still Confused with Conventional and Climb Milling

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oskar

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#1
Are the rules for conventional or climb milling the same when you work on a LATH or a MILL?

If the answer is yes, then the posts below are not correct unless I misunderstand something which is quite possible due to lack of experience.

The first link below (posts #8 and 10) which refers to LATHE work says the push the stock against the cutter for conventional milling and the second link below (post #15) which refers to MILL work says to pull the stock against the cutter for conventional milling.

After reading many documents my understanding is for conventional milling, which I prefer, is to push the stock against the cutter (cutter turns clockwise) but now I wonder if this is true.

Nicolas

https://www.hobby-machinist.com/threads/are-any-rules-how-to-feed-lock-axes.69149/#post-579034

Posts #8 and 10 says “Note that by my method, you'll be cutting "conventional" while moving the part away from you and "climb" cutting while moving the part toward you. Pay attention to the way those cuts are acting and adjust your depth of cut accordingly. Climb cutting is more risky depending on machine stiffness, condition and the particular set up.

Climb cutting can pull the part into the cut, often because of backlash clearance in the lead screw, with undesirable results. Leaving a little drag (lock) on the travel might help. You just have to get to know your equipment and process”.

https://www.hobby-machinist.com/threads/confused-with-headstock-rpm-settings.72942/

Post #15 says “First pass was climb milling, second pass was conventional”
 

Downunder Bob

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#3
Generally speaking climb milling is not a good idea especially on smaller lighter machines such as used by hobbyists.

Climb milling has a tendency to draw the work into the cutter, with subsequent damage to work and machine.

Conventional milling has the tendency to push the work away from the cutter, and will not damage either the work or the machine.

Conventional milling should always be used for all heavy cuts, like roughing work, It will allow rapid removal of material, without damage to machine or workpiece, but result in a slightly rougher surface finish.

The case for climb milling is made for an improved surface finish, but should be reserved for light finishing cuts only. I have seen too many good machines wrecked by climb milling.
 

4ssss

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#5
Climb milling gives off a better finish, so only use it to clean up and size your slot after it's been cut, if you're using an end mill. If using a circular cutter, it's not a good idea to climb mill. I've never had any luck doing it.
 

rwm

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#6
Imagine feeding a piece of wood into a table saw from the back!
Robert
 

oskar

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#10
Thanks to all for the help however I know in theory the difference between conventional and climb milling but my problem is how to apply the principles of these two techniques when I actually do work on a lathe or mill.

As I mentioned in my post, in conventional milling you feed the stock against the cutter and you do this regardless if you work on a lathe or mill

Nicolas
 

RJSakowski

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#11
I don't believe that the terms climb and conventional apply to a lathe. The cutter on a lathe is stationary so the only way to feed is to rotate the worki into the cutting edge. Rotating in the opposite direction would create a drag situation.

As to when to use climb vs. conventional milling, whether in a mill, a lathe with milling capability, or a drill press, it depends on a number of factors. As previously mentioned, a mill with any significant backlash should be operated with conventional cutting.

If the mill is tight enough so that the cutting forces don't exceed the frictional drag or cause flexing of the mill frame, and the backlash is minimal, climb milling can be used. Climb milling is preferred for modern machining as backlash is usually under .001" so there is no significant pull. It also results in less power required to make the cut, less tool wear, less chance of recutting chips, and a cleaner cut. Even so, on very heavy cuts, conventional cutting would be used because of tool flex.

Hobby class mills isually have a fairly light frame and are subject to flexing under load so climb cutting should be restricted to light cuts. Every machine has different characvteristics and cutter geometry adds another variable. The best way to determine what is best for you is to experiment for yourself.
 
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P. Waller

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#12
I don't believe that the terms climb and conventional apply to a lathe.
Milling in a lathe with the tool held in the spindle is no different the milling in a mill with the tool held in the spindle.
One may perform turning operations in a mill by holding the work in the spindle and the tool on the table.
Milling in a lathe
If a live tooled lathe.
 
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Cobra

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#13
Thanks to all for the help however I know in theory the difference between conventional and climb milling but my problem is how to apply the principles of these two techniques when I actually do work on a lathe or mill.

As I mentioned in my post, in conventional milling you feed the stock against the cutter and you do this regardless if you work on a lathe or mill

Nicolas
I am certainly not an expert but I use conventional milling to remove the bulk of the material, leaving about 5 thou or so that is removed at the end by climb milling. It is easier on my mill and yet gives me a much better finish on the cut.
 

oskar

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#14
Thank you RJ and P.Waller, very informative to me
 

Kenny G

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#15
If I understand your question you would be using a milling attachment on the late where the cutter is held in the chuck and the work is advanced by the cross slide. The chuck rotates in a counterclockwise direction on a lathe so ya it seems to me the push pull explanation for a mill would be just the opposite for the lathe. How the cutter would act as far as being pulled into the work or whatever I'll leave up to the experts. I'm pretty much a beginner too so I may be all wet.
 

RJSakowski

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#16
If I understand your question you would be using a milling attachment on the late where the cutter is held in the chuck and the work is advanced by the cross slide. The chuck rotates in a counterclockwise direction on a lathe so ya it seems to me the push pull explanation for a mill would be just the opposite for the lathe. How the cutter would act as far as being pulled into the work or whatever I'll leave up to the experts. I'm pretty much a beginner too so I may be all wet.
The chuck rotates in the same direction to the work as a mill does. Otherwise you would need to use left hand cutting tools.
 

oskar

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#17
If I understand your question you would be using a milling attachment on the late where the cutter is held in the chuck and the work is advanced by the cross slide. The chuck rotates in a counterclockwise direction on a lathe so ya it seems to me the push pull explanation for a mill would be just the opposite for the lathe. How the cutter would act as far as being pulled into the work or whatever I'll leave up to the experts. I'm pretty much a beginner too so I may be all wet.
My chuck rotates clockwise
 

Cadillac

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#18
If your work is feed into the face of the cutter “opposite spindle rotation”. That’s conventional.
Work feed in direction of spindle rotation that’s climb mill.
Grab yourself a rotary table. You’ll learn real quick which way to go. ;)
 

oskar

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#19
Not sure which is the right way for conventional milling in the attached pictures which one is for conventional milling?

Picture1 I will pull (X axis travels to my right) the stock towards the cutter
Picture2 I will push (X axis travels to my left) the stock against the cutter

I would say picture2 is conventional milling (stock pushed against the cutter)
Nicolas
 

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Cadillac

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#20
If milling on lathe. Cutter in headstock spinning normal counterclockwise. If wanting to open up a slot cutting with top of cutter you’d want to move the carriage away from you. Conventional
Cutting with bottom of cutter you’d want to be moving carriage toward operator. Conventional

Go opposite and that’s climbing. Think of the teeth on cutter. As spindle spins are the teeth climbing on the work piece or pushing away.
 

Cadillac

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#21
First picture if table moves to right that’s conventional. Second pic if table moved left it would be climbing.
 

Eddyde

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#22
My chuck rotates clockwise
Facing the front of the chuck, it turns counterclockwise in forward and clockwise in reverse.
 

magicniner

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#23
My manual milling machine has a very nice Italian made X-Y table which has very little backlash and doesn't cause problems when climb milling.
On a capable manual machine climb milling reduces the effort required to feed the cutter through the work as the cutter does some of the work.
 

oskar

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#25
First picture if table moves to right that’s conventional. Second pic if table moved left it would be climbing.
You are a "real" Cadillac mate, answers my question the best.

BTW my mill spindle turns clockwise when I look at it from the top of the mill and my lathe spindle also turns clockwise when I look at it from the front. I hope this does not change what you said about conventional milling.

When you say cutting with the bottom of cutter or top of cutter do you mean the bottom is the end (tip) of the cutter and the top of the cutter is where the flutes are?

Nicolas
 

WarrenP

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#26
Shouldn't the lathe be turning counter clockwise when looking at it from the tailstock normally?
 

atunguyd

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#27
I don't believe that the terms climb and conventional apply to a lathe. The cutter on a lathe is stationary so the only way to feed is to rotate the worki into the cutting edge. Rotating in the opposite direction would create a drag situation.
Thinking about it the closest thing I can think of with lathe work would be having your cutter above or below center height. Above center height, assuming the first doesn't rub, if the machine isn't rigid, the ford of the machine would force the cutter depth deeper resulting in problems. This would be a bit like climb milling.
Below or on centre height flex in the machine would cause the cutter to be moved out of the cut so this would be a bit like convectional milling.

I know it is not the same just closest I could come.



Sent from my SM-N950F using Tapatalk
 

P. Waller

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#28
Not sure which is the right way for conventional milling in the attached pictures which one is for conventional milling?



I would say picture2 is conventional milling (stock pushed against the cutter)
Nicolas
Both, the DIRECTION of spindle rotation determines climb or conventional, does your mill spindle not rotate in both directions (-:
 

higgite

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#29
Both, the DIRECTION of spindle rotation determines climb or conventional, does your mill spindle not rotate in both directions (-:
My mill spindle does reverse direction of rotation, but I'm having a devil of a time getting my end mills to cut in reverse. ;)

Tom
 

P. Waller

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#30
My mill spindle does reverse direction of rotation, but I'm having a devil of a time getting my end mills to cut in reverse. ;)

Tom
Turn them upside down, this should help.
 
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