How to identify climb milling?

[Chris TickTockParticipant @christicktock]

Hi Guys,

From my previous post I was helped to understand climb milling is feeding in the same direction as the end mill force. However you experienced guys see more than I am presently capable. with reference to the drawings attached which if any and more importantly why is climb milling. To me they all seem conventional, the idea is to mill a radius on the end half the diameter of the end mill.

Regards

Chris

[Chris TickTockParticipant @christicktock]

[Michael GilliganParticipant @michaelgilligan61133]

All should become clear if you put the direction of cutter rotation on those sketches, Chris

MichaelG.

[old martParticipant @oldmart]

I don't understand your diagram at all, but climb milling is when the cutter wants to roll along the work and conventional milling is when the cutter wants to roll back the way it came.

[Mick B1Participant @mickb1]

Assuming we're looking down in plan view, the climbing mill is in the left-hand one in A and the right-hand in B.

If the tooth or flute entering engagement is able to draw in the workpiece in the same direction as feed because the backlash in the approach has been taken up in the opposite direction, the tooth will have to cut the depth of the backlash plus its normal feed depth. Potential bang, if the backlash is significant.

[Colin HeseltineParticipant @colinheseltine48622]

Someone put up what I thought was quite a handy reminder of climb and conventional milling.

(may have been JasonB – but I'm not sure).

Hope this helps.

Colin

[SillyOldDufferModerator @sillyoldduffer]

My poor old brain has trouble grasping climb vs conventional diagrams without teeth, and it's what the teeth do that make the difference.

Climb milling is better in every way apart from one! Unfortunately it puts maximum stress on the machine. Bad things happen if the machine and work-holding aren't rigid. Conventional milling uses more power for the same volume of metal removed, is slower, and tends to leave an inferior finish, but it puts less force on the machine. So conventional milling is safer on worn and lightly built machines.

I do metal removing cuts conventionally but finish with light climb cuts. Even though they can't take it full throttle most well-adjusted small machines should manage shallow climb milling. Just don't overdo it!

Dave

[Chris TickTockParticipant @christicktock]

Posted by Michael Gilligan on 02/10/2020 15:38:21:

All should become clear if you put the direction of cutter rotation on those sketches, Chris

MichaelG.

Thanks Michael my error was putting the arrows in but not where they make contact. With the arrows in where they make contact all is easily understood. Thanks guys.

Chris

[JasonBModerator @jasonb]

When the direction of the cutter in contact is the same as the direction of the work they combine and become climb milling.

[Tony Pratt 1Participant @tonypratt1]

I'm the same as SOD, rough out conventionally & maybe a light climb cut to finish, this is with a Myford VME mill atm

Tony

[Martin ConnellyParticipant @martinconnelly55370]

There are good reasons for climb milling when the machine is suitable. In summary climb milling starts off cutting and ends up with a fine cut. Conventional milling starts off rubbing before cutting and at the end of the cut the sudden release of material from the cut can damage the cutting edge. This is more of a problem with large cuts than fine ones. This means that cutter life is reduced when conventional milling compared to climb milling but may be a marginal difference with home workshop machinery.

Martin C

[old martParticipant @oldmart]

SOD has the best diagram of the two types, it shows clearly the difference and why, if your bed has lots of backlash, why climb milling can grab the work and pull the lot suddenly with unfortunate results. I normally take smaller cuts/feed rates climb milling than with conventional milling.

[blowlampParticipant @blowlamp]

Also be aware that milling a pocket reverses the climb/conventional direction of travel when compared to milling the outside of a pocket.

Martin.

[Dave HalfordParticipant @davehalford22513]

None of those will give you an outside radius. The bar movement must be rotational as well. which is where the fun starts.

Hope you want an inside radius

[Bill PhinnParticipant @billphinn90025]

The most helpful and succint differentiation of the two I have seen is from 1 min 50s to 2 min 10s in the following vid.

The clockwise/anti-clockwise and internal/external basis for remembering the difference makes it much easier for me to orientate myself in the heat of an actual job.

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