Still Confused with Conventional and Climb Milling

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.
 
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.

Milling direction.PNG

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

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 :)
 
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 :)
Click to expand...

Great minds think alike!

Well, at least our minds can mimic reality anyway.
 
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.
Click to expand...

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.
Click to expand...

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