Cox Hyper Viper *** And Chipmunk, now

Looks like a nice machine Pete. Is there a vacuum-table or an option for adding one? I used to run Gerber Scientific Sabre 408's with 53" x 102" tables. I'd love to have a bench-top machine.

Yea.. I'd love to have one too! (in reply to the Jealous Mark..)

Pete, keep an eye-out for film or "filmatic" tape" (double-sided) which may be similar to what Ian suggested. "Tesa" is a brand that that I have experience with. We used it extensively when I worked at the sign company.

link to comparable product

Tesa webpage

I have Tesa #4970 in 5/16", 1/2" and 3/4" width rolls. It's approx. .005" thickness. You can use it to tack-down common 3/16" foam-board to your machine's table, as your sacrificial "spoil-board" and tack your material to be cut, to the spoil-board.. including balsa sheet.

Once you get more proficient with the CAD/CAM software, you can write a program to mill a sheet-PVC spoil-board perfectly flat using a small-dia. fly-cutter/shell-miller. The spoil-board size (sq. in. area) and the diameter of the tool will dictate the amount of time and the "step-over" per-pass needed respectively, to mill the spoil-board. If you're careful when setting the spindle's "Z-axis" (vertical-travel) when running your jobs, your spoil-board will last quite a while. You can probably program the spindle for use with a gage-plate of a certain thickness. I use to use a small rectangular (3" x 6")  .125" thick piece of acrylic-sheet to initialize my cutter to the surface. The surface can be the spoil-board itself.. or the top surface of the material being cut. The material to be cut can vary in thickness though. A properly-milled spoil-board will be near perfectly level. Care must be exercised in programming your cutting depth-parameters; depending on where you set your Z-axis. You can practice initially by programming a single drill-point and setting your plunge feed-rate LOW.....(10-20 IPM) Use a test-block of 2" Styrofoam; assuming that you have at least 2" of travel in your Z-axis with a tool in the spindle. You're less likely to have a damaging Z-axis crash, if you set/initialize well above the spoil-board on your first trials. You'll also have more time to react and stop the machine if the plunge is going too deep.

Your Z-lift between cuts, must clear the work-piece. I used to set this parameter to .250" above the total thickness of the material to be cut, which saves time vs. the spindle completely retracting after every cut. There should be a parameter for setting.. and possibly a fail-safe point above the programmed total-depth.

I have cutters that may interest you. They fit a 1/8" collet. They are not new.. but most have good life left in them.




They're a single-flute hybrid up-spiral. I typically ran them at 20K rpm in Perske 7HP high-frequency spindles. We found this tool superior to Gerber's "Gold" (Titanium-Nitride coated) solid-carbide 2-flute up-spiral, particularly when cutting PVC. The hybrid tool cut cleaner and lasted longer. Cleaner meant less labor-time in sanding "fuzz" off the cut edges. All cutting was done dry. Feed-rates depend obviously on the material being cut and the depth of cut. These endmills will cut mild Aluminum, acrylic, MDF, plywood.. and many other materials. The key is in holding the material in place. Keeping your feed-rate low can prevent the work-piece from slipping out from under clamps. When using clamps; run a simulation/animation of the program before spooling the job to the router. This will show you were clamps can be placed so that the spindle safely clears them. The "home" and "park" positions of the spindle on your machine can be customized.. I would think.

A trick for securing material.. is cutting blocks the same thickness or less of your material.. and facing one side with the double-stick tape. Place the blocks around the perimeter of your work-piece and stick them down on the spoil-board snugly to prevent any movement. Set the depth of cut .005" or more above the spoil-board.. and your pieces won't move while cutting. This leaves a .005" web of retaining-material that easily breaks-free when you remove the work-piece from the table. This works particularly well with balsa. You don't want to have to pick/pry balsa parts off, that have been taped-down to a spoil-board.  

Vacuum-tables are nice. Making your own isn't out of the question. A pump, manifold-box and valve is about it. PVC spoil-pads for it, can be made on your machine with a simple drill/pocket grid-program. The valve controls the suction and is sized/adjusted to keep the pump from overheating during continued operation. I'll elaborate more if that interests you.

I hope this wasn't over-load..   I'm really psyched that you got this machine! PM me if you're interested in trying the cutters.

P.S. Cool Chipmunk!!!!!