I finally made it out onto the shop floor, running some machines. below are a few samples of the most recent chip-breaking agenda:
this is a practice piece for the radial arm drill press, just a series if holes, the largest of which was 1.375", an enormous bit. thats a quarter to the right for scale. The pilot hole for a bit of this size is still only around 0.25", as the web is no thicker than that across the point. If i remember right, the spindle speed was less than 200 RPM and a feed of around 0.008"/rev. When the cutting face hit the work a shitstorm of smoke and chips curled out from the flutes and the floor shook. pure horsepower, it was impressive. here's one of the chips, a nice copper-red color from the heat:
as a cutting tool is fed into a workpiece, under the right conditions (good rigidity and cutting tool geometry, proper spindle speed and feed rate, etc.) a uniform chip is produced by the shearing forces as the crystalline structure of the metal is continually compressed and sheared, forming peaks, over and over again. under power feed, those peaks can be seen on the chip form as serrations, resulting in a coil like this:
next: bigger chips, heavier cuts, and tapers...
