Drilling feed rates

[Beardy MikeParticipant @beardymike]

My mill is a kx3, which has no quill – the only way to drill is to set a feed and let the motors do the work. While I’m very happy on a drill press adjusting feed by feel and the look of the chips, I’m having trouble putting a number to it (and am too slow to react on feed override when I can see it’s wrong).

I typically use the little machine shop calculator for milling feeds and speeds with good results, but when I take its numbers for drilling I just toast the drill and ruin things. Does anyone have a calculator that works better for hss drills in steel, aluminium, stainless etc.?

[JasonBModerator @jasonb]

As I use F360 for my CAM I tend to take their speeds ( subject to 5000rpm max) but use around 40% of the feed rate per rev. The feed rates per rev are fairly constant for all the materials they list and only change when you look at them as mm/min when the speed comes into play

So a 3mm drill will typically feed at 0.02mm/rev and a 6mm drill feed at 0.03 to 0.04. I don’t have flood cooling so that is one reason to reduce it and once more than about 1 x diameter deep will use “full retract” which is what they call peck drilling to reduce risk of swarf buildup in the hole and allow brush or fogbuster to get some cutting fluid on the drill.

Not cooked any drills yet. Tend to use Dormer A022 Stub length most of the time

Typical F360 chart and what I run

 

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