Power tapping test results

[PixMan]

Well, I cut the piece to halfway through the tapped hole to see what it looked like inside. It was a sacrificial piece anyhow, no loss.

Here's a video of my machine face milling the 1018 CRS down. It's a .075" depth of cut (just shy of 2mm) and feeding at 20 inches per minute at nearly full width of the cutter. I probably could have gone a deeper depth of cut for fewer passes because the machine spindle didn't seem to mind the cut. I made a decent little pile of chips in about 10 minutes. I could have done it faster if I written a program, but that takes nearly as long as the "semi-manual" way of punching in a feed rate once and a distance to go for each pass. I ran in one direction to throw all the chips in one place.

This is the 2-1/2" 4-insert cutter after milling about 6-1/2 cubic inches of steel into little chips, some of it across an interrupted cut (the hole in the part.) I had the tougher, multi-purpose grade WSP45 inserts in the cutter, though if I had much more to do I would have switched to the steel & cast iron only grade WKP35S.



Here's the 1:16 video showing a few passes. Remember, this is a 2HP belt driven spindle running in high range @ 730 rpm and 20 inch per minute feed for a .0068" feed per tooth.




Now a look at the blind hole I tapped yesterday. The tap appears to have come to between 1/8" and 5/32" (3 to 4mm) of the bottom of the hole. With the 2 to 3 thread lead (at .100" lead), that's at least another 1/4" of hole not fully threaded. The thread calculates by hole size to be 71% thread, I think it's closer to 65%. Good looking quality to the thread though.




And my pile of chips from milling.  Note my new shop broom, a Weiler (brand) #44007 Palmyra fiber one. It doesn't get any chips sticking to it! $29.19 from Amazon, free shipping for stocking up on the WypAll X60 shop wipes at the same time.