The vertical stand was salvaged from a Sheffield comparator, obtained from an auction long ago. The extra weight is shown removed. It adds a couple of pounds to provide more stability. The head can slide up and down, and has a very fine adjustment if desired. The assembly is very stable, especially with the added weight.
Here the head assembly is removed, to show a better view of the linear slide. There is zero "slop" in any axis, at least that I can measure. The 200 step motor and 10-32 leadscrew result in a very smooth burn. I still have to "play" with the voltage window pots however, to obtain minimum up and down movement when burning.
The 1/2" drill rod on the back of the assembly will fasten either to the toolpost, or I can insert it in a drill chuck on the vertical mill. Then the accuracy of the X - Y movement afforded by the mill table provide a very accurate positioning mechanism.
Here are a couple of examples of just playing around. The left shows a couple of 1/16" holes burned through a high speed steel lathe bit. Also is a piece of file with holes burned through. The file holes took about 5 minutes. The HSS toolbit took between 10 and 15 minutes.
On the right is a 3/8" HSS toolbit, with a 1/4" square hole burned through. That burn took about 1 hr and 20 minutes. I used Kerosene on the pieces on the left, and well water for the piece on the right. I plan on trying distilled water (collected from my shop dehumidifier) for some future tests.
