Wednesday, March 8, 2017


The work on my CNC mill enclosure is idling a few days because of finding I was missing a couple of screws.  These aren't called out on the DVD I bought; the entire enclosure project isn't on the DVD.  There has been some discussion on the CNCZone forum about it, where I got most of the hardware list, and a handful of videos on YouTube.  While watching a couple of those videos for the third or fourth time, I noticed a couple of screws I had missed.  After spending half an hour at Lowe's looking for #6 pan head wood screws, I didn't think I'd find M3 x0.5 screws in the oddball length I need, so it was off to Bolt Depot where I got everything I thought I could possibly need, and some spares.  Like most of my Bolt Depot orders, the hardware I ordered was about half the price of shipping: $2.24 for the hardware and $4.95 for the shipping.   The hardware should be here tomorrow.

It's also idling because while cutting the clear acrylic for the front doors, I broke two pieces.  It's a comedy of errors thing.  Such comedies aren't usually funny for a while when they happen to you.  

On the positive side, the other three panels are all up and the basic enclosure is built.
The structure uses latches to hold the sides to the back, one is visible at the top of the right corner, and also uses latches to hold the sides to the chip tray.  The picture below is a detail zoom of the right side top and bottom latches, along with another L bracket with two screws in it which attaches the side to the back.  To take this apart, I remove one screw from that L bracket and one from a matching bracket on the left side, then pop latches open. 
If you look behind the mill, you'll see a PVC pipe sticking up with two 90 degree elbows on it.  Those feed the wires from outside the enclosure up into the chip tray and the tube is sealed to keep coolant from getting out of the tray. 

Once this is done, the rest of the "To Do" list becomes smaller projects.  In no particular order:
  • Get oil for oiler and get it working. 
  • Get coolant system running.
  • Edge finder using electrical contact. 
  • Limit switches
  • Get rotary axis working
  • Spindle speed & on/off control
It's usable for projects now, maybe like this one...  Those upgrades are primarily to increase friendliness and usability. 


  1. Acrylic is brittle. We cut a lot of 2mm thick and use a negative hook triple chip blade on the table saw. Sometimes we use a straightedge and score it with a laminate knife and break it, but it has to be supported on an edge, along the break, and have a piece on top, to lever it over all along the score mark. Risky though. One wrong snap and a couple hundred bucks down the hole.

    1. The first sheet I cut came out excellently. I scored it several times, then cut it with a jig saw. The second one I cut without scoring it at all and it cracked near the edge - but not too badly. These were last week.

      I figured a lesson there was to score it even if I cut it with the jigsaw. I had swapped the blade for a coarser one to cut the PVC pipe with, and when I went back to a finer tooth blade, I made two mistakes. The first was not to notice I was working with two sheets stuck together, so twice the thickness. To compound that, I think I went to a finer blade. The result of a too fine blade on too thick piece of plastic was a lot of melting on the edges. I'd complete the cut with the jig saw, and move the saw off the edge, only to find the previously cut edges melted together. The crack happened as I tried to break off some of the melted plastic. It got worse when I realized it was two sheets melted onto each other.

  2. Rueful experience teaches that the fiddly bits take much longer than planned.
    We cut some acrylic sheets by scoring and then snapping like glass, but still ran into the cracking problem on some cuts.
    My experience with using a hole saw to cut a disk from Lexan ended up with a hole saw seized about halfway through the cut, and the saw was welded so thoroughly into the hole by the melted plastic that I had a rough time getting it free.
    The bandsaw cut the plastics very well, but the throat depth limited the sizes. Maybe because the blade's length minimizes overheating, and the speed removes the material without as much friction heating of the plastic.

  3. SiG, I'm impressed that you would admit you were missing a couple of screws. I'm missing more than a couple, but I've tried to be discreet about it. :-)