# Still Confused with Conventional and Climb Milling



## oskar (Oct 15, 2018)

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”


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## P. Waller (Oct 15, 2018)

If milling in a lathe the same principles apply.

https://www.harveyperformance.com/in-the-loupe/conventional-vs-climb-milling/


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## Downunder Bob (Oct 15, 2018)

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.


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## Eddyde (Oct 15, 2018)




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## 4ssss (Oct 15, 2018)

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.


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## rwm (Oct 15, 2018)

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


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## 4ssss (Oct 15, 2018)

rwm said:


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



Good description.


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## oskar (Oct 15, 2018)

P. Waller said:


> If milling in a lathe the same principles apply.
> https://www.harveyperformance.com/in-the-loupe/conventional-vs-climb-milling/



And when I mill on a mill the same principles apply?

Nicolas


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## Cobra (Oct 15, 2018)

oskar said:


> And when I mill on a mill the same principles apply?
> 
> Nicolas


Yes


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## oskar (Oct 15, 2018)

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


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## RJSakowski (Oct 15, 2018)

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 (Oct 15, 2018)

RJSakowski said:


> 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 (Oct 15, 2018)

oskar said:


> 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.


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## oskar (Oct 15, 2018)

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


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## Kenny G (Oct 15, 2018)

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.


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## RJSakowski (Oct 15, 2018)

Kenny G said:


> 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.


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## oskar (Oct 15, 2018)

Kenny G said:


> 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


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## Cadillac (Oct 15, 2018)

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.


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## oskar (Oct 15, 2018)

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 (Oct 15, 2018)

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.


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## Cadillac (Oct 15, 2018)

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


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## Eddyde (Oct 15, 2018)

oskar said:


> My chuck rotates clockwise


Facing the front of the chuck, it turns counterclockwise in forward and clockwise in reverse.


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## magicniner (Oct 15, 2018)

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.


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## Old Rivers (Oct 15, 2018)

P. Waller said:


> If milling in a lathe the same principles apply.
> 
> https://www.harveyperformance.com/in-the-loupe/conventional-vs-climb-milling/



Very good explanation, thanks for posting. The bit about the role of backlash makes perfect sense, something I hadn't thought about.

Bill


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## oskar (Oct 15, 2018)

Cadillac said:


> 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


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## WarrenP (Oct 15, 2018)

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


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## atunguyd (Oct 15, 2018)

RJSakowski said:


> 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


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## P. Waller (Oct 15, 2018)

oskar said:


> Not sure which is the right way for conventional milling in the attached pictures which one is for conventional milling?
> 
> 
> 
> ...



Both, the DIRECTION of spindle rotation determines climb or conventional, does your mill spindle not rotate in both directions (-:


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## higgite (Oct 15, 2018)

P. Waller said:


> 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


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## P. Waller (Oct 15, 2018)

higgite said:


> 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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## oskar (Oct 15, 2018)

To add to my confusion now we added the headstock rotation, LOL.

I’m glad though because I never paid attention to this critical task. I use a Sherline VS 90VDC motor with a KBIC controller for both my lathe and mill. I only have to remove two 10-32 SHCS to switch the motor from the lathe to the mill. The KBIC controller does not have a reverse switch; it only has an ON/OFF switch and a VS knob for the speed.

Right now the Taig lathe turns clockwise when viewed from the tailstock and the Taig mill also turns clockwise when viewed from the top. But it looks like I have the rotation wrong and I have to verify this before proceeding to reverse the wiring and have both the mill and lathe turn CCW.

The Sherline motor is supplied with 120VAC and to switch the rotation I guess I have to switch the black and white wires. Now they are connected black to black and white to white. Any one knows how to change the wires to reverse the rotation?

I completed the V-Groove in several passes and I made a YouTube video from one of the passes






Nicolas


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## higgite (Oct 15, 2018)

P. Waller said:


> Turn them upside down, this should help.


Ha! Nice try, but I ain't falling for that old trick. I'll just mount the work piece backwards in the vise.

Tom


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## Winegrower (Oct 15, 2018)

All this push or pull stuff is silly.   Look at the cutting edge of the tool.   As it turns, where a chip is coming off, if the tool edge is moving opposite the way the part is moving, it’s conventional.  If the tool edge is moving in the same direction as the work, it’s climb milling.   Same on lathe, mill table saw, router, etc.


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## oskar (Oct 16, 2018)

Very nicely said Winegrower, thanks

Nicolas


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## Highsider (Oct 19, 2018)

oskar said:


> 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.
> 
> ...


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## Highsider (Oct 19, 2018)

Even the best conventional vs climb milling illustrations can be confusing.  Trust me tho, after you have had your workpiece gobbled by your machine tool once, they will make perfect sense!   Sorry not to be of more help than this.


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## P. Waller (Oct 19, 2018)

Bloody Hell, this is the one of the most simple decisions made in a machine shop.
The question with a manual machine is not climb or conventional mill, it is can I climb mill at all without breaking anything.
If you can make the machine climb then do so at all times as you will save time and tooling costs.
If it will not climb then you are stuck with conventional milling, this applies to lathe milling or milling machine work equally.

Single point lathe work has no climb/conventional option, the tools only have 1 cutting direction that will work.


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## BaronJ (Oct 19, 2018)

Basically if your work is moving in the same direction as the cutter then you are climb milling !


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## epanzella (Oct 20, 2018)

Maybe I'm oversimplifying this but as I see it when convention milling if your pushing for the feed the teeth of the cutter should be pushing back the opposite way, resisting the feed and keeping backlash at bay.  If you're pulling for the feed, the teeth of the cutter should be pulling the opposite way, again resisting the feed and eliminating backlash. So trying to determine the type of milling by wether the feed is pushing or pulling doesn't really work. Now I assume plunging a center cutting end mill into the work essentially drilling a hole is called plunge milling but is it still called plunge milling when you extend the hole to make a slot? It seems if you're cutting a slot the full width of the end mill you're climb milling and conventional milling simultaneously. I never knew what to call that.


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## oskar (Oct 20, 2018)

epanzella said:


> ........So trying to determine the type of milling by wether the feed is pushing or pulling doesn't really work. Now I assume plunging a center cutting end mill into the work essentially drilling a hole is called plunge milling but is it still called plunge milling when you extend the hole to make a slot? It seems if you're cutting a slot the full width of the end mill you're climb milling and conventional milling simultaneously. I never knew what to call that.



That's a good question for someone with experience to answer


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## mikey (Oct 20, 2018)

Plunging with a center cutting end mill is a plunge cut. Plunging with a non-center cutting end mill requires you to drill a hole to clear the center of the hole before plunging with the end mill, in which case it is still called a plunge cut.

A slotting cut is called a slotting cut, whether you plunge the end mill in first or drop it into a pre-drilled hole to start the slot. If you are cutting the slot with both sides of the end mill at the same time then you are cutting "conventionally" on one side and "climb cutting" on the other side at the same time, and it doesn't have a name other than slot cutting. 

If you are using an end mill to widen an existing slot then typically you would either climb or conventional cut each side, your choice. In a slot it is probably better to conventional mill it to reduce vibration if you have a light spindle or thin end mill or if the slot is deep for the diameter of the cutter.


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## mikey (Oct 21, 2018)

Nic, this conventional vs climb thing is confusing as hell at first, and all of us go through this conceptual confusion in the beginning so don't feel like the Lone Ranger. The thing that might clarify this for you is to think about it in terms of the *direction of feed *of the part you're cutting relative to the point of contact and rotation of the cutter.

When conventional milling, the direction of feed is always opposite the direction of rotation of the cutter.
When climb cutting, the direction of feed is always the same as the direction of the cutter.
What gets you is that the point of contact of the end mill with the part varies with where you are on your part so maybe this might help.




Here, (EDIT: you're looking down on the part in the above view) the end mill is red and the rotation of the end mill is always CW, right? Depending on which edge of the part you're cutting on (cuts on the edges are called Profiling cuts), table feed direction varies. The arrows show you which direction the table feed is going in when Conventional cutting. A climb cut will require the table to move in the opposite direction.

Because your mill is very light, it is best to conventional mill whenever you can. You can make a conventional cut until you're almost at size, then dial in a few thou and take a climb cut to produce a nice finish.

Hope this helps.


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## oskar (Oct 21, 2018)

Can go wrong with that Mike, thanks

You are right, the problem was that I always had to think which side of the work the endmill is to interpret the cut and although I had made some sketches of my own, I was not sure.

Now with your explanation and your sketch, milling will be easier.

Regarding the plunge cut I also had the same question and you answer clears this question too.

Thanks again


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## mikey (Oct 21, 2018)

Yup, from one previously confused person to another, you're welcome.


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## P. Waller (Oct 23, 2018)

epanzella said:


> Maybe I'm oversimplifying this but as I see it when convention milling if your pushing for the feed the teeth of the cutter should be pushing back the opposite way, resisting the feed and keeping backlash at bay.  If you're pulling for the feed, the teeth of the cutter should be pulling the opposite way, again resisting the feed and eliminating backlash. So trying to determine the type of milling by wether the feed is pushing or pulling doesn't really work. Now I assume plunging a center cutting end mill into the work essentially drilling a hole is called plunge milling but is it still called plunge milling when you extend the hole to make a slot? It seems if you're cutting a slot the full width of the end mill you're climb milling and conventional milling simultaneously. I never knew what to call that.


You are correct, if you use an endmill to make a slot that is the diameter of the tool one side is climb milling and one side is conventional milling.
You simply do not do that if you require a nice finish and an accurate width slot.
In the year 2018, rough it small then climb the final cut all the way around including the radii at each end with a smaller tool.
This year is not 1947 after all, technology has improved a a bit, embrace it.


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## ThinWoodsman (Oct 24, 2018)

mikey said:


> Here, (EDIT: you're looking down on the part in the above view) the end mill is red and the rotation of the end mill is always CW, right? Depending on which edge of the part you're cutting on (cuts on the edges are called Profiling cuts), table feed direction varies. The arrows show you which direction the table feed is going in when Conventional cutting. A climb cut will require the table to move in the opposite direction.



That's exactly the diagram I hand-drew and taped up next to the Taig mill I bought when I got started in all this


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## oskar (Oct 24, 2018)

ThinWoodsman said:


> That's exactly the diagram I hand-drew and taped up next to the Taig mill I bought when I got started in all this



I did the same, a BIG thanks to Mike


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## mikey (Oct 24, 2018)

ThinWoodsman said:


> That's exactly the diagram I hand-drew and taped up next to the Taig mill I bought when I got started in all this



Great minds think alike!

Well, at least our minds can mimic reality anyway.


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## BaronJ (Oct 24, 2018)

P. Waller said:


> You are correct, if you use an endmill to make a slot that is the diameter of the tool one side is climb milling and one side is conventional milling.



Not strictly true !  It is conventional milling.  The cutting is taking place in the direction that the cutter is moving, in the arc formed by the diameter of the cutter.  



> You simply do not do that if you require a nice finish and an accurate width slot.
> In the year 2018, rough it small then climb the final cut all the way around including the radii at each end with a smaller tool.
> This year is not 1947 after all, technology has improved a a bit, embrace it.



I agree that if you want an accurate width slot then clean up the sides with a smaller cutter.


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## PCT (Oct 24, 2018)

rwm said:


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


Which would be an example of conventional milling.


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## mikey (Oct 24, 2018)

PCT said:


> Which would be an example of conventional milling.



No, it would be a climb cut if fed from the back. Actually, it would be a climb throw when the blade bit in.


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## higgite (Oct 24, 2018)

BaronJ said:


> Not strictly true !  It is conventional milling.  The cutting is taking place in the direction that the cutter is moving, in the arc formed by the diameter of the cutter.
> 
> 
> 
> I agree that if you want an accurate width slot then clean up the sides with a smaller cutter.


True that all of the cutting is in the 180 degree arc on the leading half of the end mill. but it seems to me that the cutter is conventional milling as the cutting edge enters the arc and climb milling as it exits the arc with a transition in the middle. Maybe that’s why it’s called slotting instead of conventional or climbing? Those terms do apply when  the sides of the slot are being cleaned up or the slot is being enlarged with an end mill smaller than slot width. 

But, I could be wrong. I was once. 

Tom


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## WarrenP (Oct 24, 2018)

mikey said:


> No, it would be a climb cut if fed from the back. Actually, it would be a climb throw when the blade bit in.



Haha , it sure would be climb THROW.


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## P. Waller (Oct 24, 2018)

BaronJ said:


> Not strictly true !  It is conventional milling.  The cutting is taking place in the direction that the cutter is moving, in the arc formed by the diameter of the cutter.
> 
> 
> 
> I agree that if you want an accurate width slot then clean up the sides with a smaller cutter.






If you are milling a slot at the cutter diameter with a round tool in one pass one side will always be climbing and the other conventional.
This is unavoidable in such an operation using a rotating tool.
If you have ever done this you will notice that the side of the slot that was climbing has a noticeably better finish then the other side.


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## rwm (Oct 24, 2018)

I the diagram above, when you say "feed direction" are you feeding the stock or feeding the tool?
This page discusses it well and also discusses the importance of the application.
https://www.harveyperformance.com/in-the-loupe/conventional-vs-climb-milling/
Robert


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## P. Waller (Oct 24, 2018)

rwm said:


> I the diagram above, when you say "feed direction" are you feeding the stock or feeding the tool?
> This page discusses it well and also discusses the importance of the application.
> https://www.harveyperformance.com/in-the-loupe/conventional-vs-climb-milling/
> Robert


The tool, in this scenario that is unimportant as one side will be climbing and one side conventional milling at all times regardless of feed direction.
The Harvey tool illustrations pretty much explain the entire concept. What could be more simple to understand?


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## higgite (Oct 24, 2018)

Original message deleted. Never mind. Didn't intend to start a shouting match.

Tom


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## P. Waller (Oct 24, 2018)

This is unimportant when milling BOTH SIDES OF A SLOT in one pass with a ROUND tool held at a RIGHT ANGLE to the work.
The feed direction is has no effect on the work aside from machine and tooling deflection.


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## T Bredehoft (Oct 24, 2018)

One point not yet covered,

When conventional milling, the cutter is sneaking into the cut, just barely scraping the material as it enters the work. 

When climb milling, the cutter takes a big bite as it enters the work and leaves, scapeing the thin  surface.

I suppose this just confuses those who haven't experienced it.


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## BaronJ (Oct 25, 2018)

P. Waller said:


> The tool, in this scenario that is unimportant as one side will be climbing and one side conventional milling at all times regardless of feed direction.
> The Harvey tool illustrations pretty much explain the entire concept. What could be more simple to understand?



How can you climb mill when there is little or no material to cut when slotting !  Yes the tool will rub and the trailing side will get polished.
The Harvey tool post explains it well, but unfortunately doesn't deal with slotting.


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## higgite (Oct 25, 2018)

Deleted. Sorry. 
Note to self: Never type before coffee kicks in.

Tom


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## RJSakowski (Oct 25, 2018)

I think one of the confusing issues is what is the direction of feed.  The Harvey paper shows the direction of feed as the direction the cutter is moving relative to the work.  When we feed with a mill, the cutter is stationary and we feed the work into it.  The two are opposites.  It doesn't help that in some of the illustrations, it isn't clear which is being referred to.


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## WarrenP (Oct 25, 2018)

BaronJ said:


> How can you climb mill when there is little or no material to cut when slotting !  Yes the tool will rub and the trailing side will get polished.
> The Harvey tool post explains it well, but unfortunately doesn't deal with slotting.



It seems to me that when cutting a slot by the illustration above you can see that the conventional cutting side is only cutting one side of the slot and the climb cutting side is cutting the other side of the slot. How else would the "climb" side be cut to size without that side cutting also? The "conventional" side doesn't touch the other side.


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## BaronJ (Oct 25, 2018)

Hi Warrren,

Get a lump of material and try it for yourself.  Start cutting a slot.  There is no climb milling at all !  Now back out of the slot you have just cut,  ignoring spring, no material will be removed.  When you back out you will be moving your cutter in the climb milling direction !

Now if you have a machine with a worn spindle or a worn table, there might be enough slap to cause the cutter to rub more heavily than it might.


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## higgite (Oct 25, 2018)

That illustration is a little misleading when we're talking about slotting because the cutter is shown in the middle of the slot lengthwise. That's not how a slot gets cut. When slotting, regardless of direction of feed, each flute/cutting edge will enter the cut as conventional milling and exit the cut as climb milling. You have no choice like you do when you're cleaning up a slot or widening it with a smaller end mill.

Tom


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## ThinWoodsman (Oct 25, 2018)

Just a quick thought experiment.

Let's say you're conventional-milling the edge of a plate. You decide to use the entire diameter of the cutter (instead of 1/3 or 1/2 or whatever your personal rule of thumb is) in order to remove more metal in fewer passes, despite all the noise. Unfortunately you move the cutter too far inwards and have left a web of maybe 0.05" on the outer edge of the plate. You are now, in fact, cutting a slot.

At what point does it stop being conventional milling? Maybe when 1/2 the diameter of the end mill is cutting?


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## BaronJ (Oct 25, 2018)

Hi ThinWoodsman,

It doesn't !  Cutting sideways into a surface is always conventional milling.  
Cutting an edge traveling in the same direction as the cutter is turning is climb milling.

Using your example:
Once you start to move the cutter into the workpiece, the area of the cut increases until the full tool diameter is reached !
Once that happens you are right, you are now cutting a slot.  The whole diameter of the cutter is now removing material, there is no material left to climb mill.


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## mikey (Oct 25, 2018)

higgite said:


> True that *all of the cutting is in the 180 degree arc on the leading half of the end mill. but it seems to me that the cutter is conventional milling as the cutting edge enters the arc and climb milling as it exits the arc with a transition in the middle.* Maybe that’s why it’s called slotting instead of conventional or climbing? Those terms do apply when  the sides of the slot are being cleaned up or the slot is being enlarged with an end mill smaller than slot width.
> 
> But, I could be wrong. I was once.
> 
> Tom



I'm with Tom and @P. Waller here. It makes no difference what you call it. When cutting a slot with the end mill fully engaged, the end mill is cutting in both conventional and climb modes at the same time and it cannot do anything else. 

Most of us rarely do a full width cut unless we just need a slot. If it has to be an accurate slot with decent finishes then we will use an undersized end mill to rough it and come back with a finishing end mill to climb or conventional cut the sides and ends.


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## ThinWoodsman (Oct 25, 2018)

BaronJ said:


> Hi ThinWoodsman,
> It doesn't !  Cutting sideways into a surface is always conventional milling.
> Cutting an edge traveling in the same direction as the cutter is turning is climb milling.



That was my thinking too. But that scenario helped me put the problem in perspective


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## higgite (Oct 25, 2018)

I’m going to go out on a limb here and say that the terms conventional milling and climb milling only apply to side milling and that slotting is neither conventional nor climb. It’s slotting. And that's what I'm going to call it. 

Now that that’s settled for all time. What is plunge milling, conventional or climb? 

Tom


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## P. Waller (Oct 25, 2018)

RJSakowski said:


> I think one of the confusing issues is what is the direction of feed.  The Harvey paper shows the direction of feed as the direction the cutter is moving relative to the work.  When we feed with a mill, the cutter is stationary and we feed the work into it.  The two are opposites.  It doesn't help that in some of the illustrations, it isn't clear which is being referred to.


The direction of cut is the direction that the tool moves relative to the work, this does not change if the tool moves or the work moves.
Let me explain this again. If someone finds this terribly difficult to understand then they will probably never get the principle.


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## P. Waller (Oct 25, 2018)

higgite said:


> I’m going to go out on a limb here and say that the terms conventional milling and climb milling only apply to side milling and that slotting is neither conventional nor climb. It’s slotting. And that's what I'm going to call it.
> 
> Now that that’s settled for all time. What is plunge milling, conventional or climb?
> 
> Tom


A side milling cutter can either climb or conventional cut depending on the feed direction, you may also plunge a side mill.
https://www.travers.com/side-milling-cutters/c/297777/
https://www.mscdirect.com/browse/tn...archterm=side+milling+cutter&navid=4287922886


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## mikey (Oct 25, 2018)

higgite said:


> I’m going to go out on a limb here and say that the terms conventional milling and climb milling only apply to side milling and that slotting is neither conventional nor climb. It’s slotting. And that's what I'm going to call it.
> 
> Now that that’s settled for all time. What is plunge milling, conventional or climb?
> 
> Tom



It's neither; it's plunging.


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## higgite (Oct 26, 2018)

mikey said:


> It's neither; it's plunging.


Aw, Mike, now you done gone and spoiled it. I figured that had to be worth 3 more pages. 

Tom


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## WarrenP (Oct 26, 2018)

mikey said:


> I'm with Tom and @P. Waller here. It makes no difference what you call it. When cutting a slot with the end mill fully engaged, the end mill is cutting in both conventional and climb modes at the same time and it cannot do anything else.
> 
> Most of us rarely do a full width cut unless we just need a slot. If it has to be an accurate slot with decent finishes then we will use an undersized end mill to rough it and come back with a finishing end mill to climb or conventional cut the sides and ends.




+1 with Mikey, I have to agree it has to be both. Once the  cutter gets to 180 degrees, or the other side it is cutting oppposite of the first 180 degrees, which means it is cutting both conventional and climb depending on which side is doing the cutting. The other side has to be cut too and then the  cutter is turning opposite of the first side.


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## BaronJ (Oct 26, 2018)

Hi Guys,

You can only plunge a center cutting slot drill or end mill.


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## mikey (Oct 26, 2018)

Actually, if you drill a hole first you can plunge with a non-center cutting end mill.


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## T Bredehoft (Oct 26, 2018)

I think we're obsessing about something that needs to be experienced. Slotting is a whole 'nother kettle of fish. Generally there is enough load on the  end mill to pull it sideways as it cuts, so we generally use a smaller mill cutter and rough it in one pass and finish by Climb milling both sides. one at a time. 

Lets all step back, take a deep breath, put some stokc in the mill and make some chips, paying strict attention to what we and the cutter are doing. 

Then lets come back here and admit that we now know what we're doing.


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