When I bought the NM200 in 2010, I stupidly asked for the tall column version, thinking that I'd magically get more Z travel along with Z space. The result of this version is that the spindle can't get close to the table, or even to a vise on the table. Luckily I owned a 8" tilt table, and with access to surface grinder at school, I was able to grind the top and bottom flat and parallel. With this table mounted to the Novakon table and a Kurt vise on top, I've been able to get along nicely as long as the stock isn't too big. For stock much longer than the vise's 6", I've been using a pair of 12" soft jaws from Monster Jaws.
The spindle nose still can only get to about 2.5" above the tilt table, so today's project was to raise it by 2" using a pair of 2-4-6 blocks.
I intend to mount a vacuum chuck from Pierce Workholding in order to machine some sheet material. Which brings me to the point of this post.
While the items I'm cutting from the sheet need to be through cut eventually, I can't do so without releasing the vacuum. So I need a target depth just less than the material thickness. How little material can I leave without causing problems? Stock is aluminum from 1/8 to 1/8 thickness, and acrylic 1/8 and 1/4.