Milling – Speed and depth advice

[Nick_GParticipant @nick_g]

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Hi guy's.

I have to mill out a piece from EN3.

I have a 3 fluted 6mm slot drill. (there is a reason it's 6mm) This is a carbide one so I realise it will be more brittle than a HSS one so will snap if I get too enthusiastic. It's a new one so will be sharp.

Question is what sort of depth cut would be reasonable to take on each pass and aprox speed for such a cutter into EN3

Cheers, Nick

[Nick_GParticipant @nick_g]

[David Clark 13Participant @davidclark13]

A lot will depend on the coolant available. Also if cutting a keyway it should be done in one pass. Speed about 3000 if available should be fine with lots of coolant. Probably about 25mm per minute feed.

[AjohnwParticipant @ajohnw51620]

With HSS I reckon on a max depth of cut of around the diameter of the cutter. Can't see why carbide should be any different really but have never used slot mills of that type.

Speed can be similar to what would be used in a lathe with the same type of tool and material being cut except its the tool that is rotating. Generally I run slower than suggested figures as I like my tool to stay sharp.

Feed in my case is by hand so I haven't a clue what it is in mm / min. I generally adjust that to get a decent finish and by looking at how it cuts. If a cutter is taking what for it is a deep cut it will bend somewhat on smaller sizes. Too much of that will spoil the finish. Much of that sort of thing depends on just how powerful a miller is.

John

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[KWILParticipant @kwil]

1mm deep, 3000rpm dry, any deeper with coolant or air to remove the swarf.

[Nick_GParticipant @nick_g]

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Cheers guy's

Nick

[Neil WyattModerator @neilwyatt]

I saw several similar sized keyways cut in one pass on a big 'bridgeport' yesterday, in stainless (I think)

The benefits of big solid machine were very obvious

Neil

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