The first one ordered worked 1 time, probably 30 minutes while I was familiarizing myself with the unit. Then he froze. The second seemed DOA. But. I've tried a few things and it turns out that the mount I'm using isn't conductive. I placed a piece of scrap aluminum between the milling machine table and the workpiece. And voila! It works out. So review correction: 1 star to 4 stars, no refund. Still -1 star because I can't be the first to encounter this issue and I'm wondering if there haveβ¦