Success! I finally tested this 40mm APKT mill. I first had to make a MT2 shell mill holder with threaded drawbar (a long story for another posting). The 40mm, 4-flute, APKT major brand face mill was designed to be mounted on a 19mm shell mill holder with two driving lugs.
Conditions: BMS. 1mm depth of cut. 6mm width of cut at 600 rpm. For pacing the feed I counted at 1 turn of the handwheel in six seconds. The handwheel is marked with .100" per turn, so my maths put that at 1" per minute, (25mm per minute) which seemed very slow and difficult to maintain The work was to the front of the spindle, moving left to right. The spindle with facemill was behind the work cutting conventionally and the chips flying away from me.
Not knowing how best to proceed, I approached this test as if this were a HSS 4-flute endmill, right down to the width and depth of cut, sans cutting oil (I am not prepared to use coolant in a domestic setting).
The chips were small "c" shape and 1.5mm diameter, bright silver color. But, the chips sprayed horizontally, even into my toolbox one meter distant. I will have to set up a chip barrier to avoid this "chips ahoy".
The finish was good, but there was too much hammering for my sensibilities, which no doubt reflects on my inability to know how to use this carbide facemill. (I did try 900 rpm and double the feed, but the noise/hammering was louder). Hard to measure without a Db meter.
Does anyone know how best to use a positive-rake carbide facemill? All suggestions are welcome and appreciated.
Paul