3 Axis Foam Cutting Mill

3 - Axis Foam Cutting Mill - Part 14

Mill-Head Mount

I made these brackets to mount the home & limit sensors on the mill earlier in the week.

In the process of testing the home & limit lines, I found that I couldn't get them to work. The limit sensor, would cut the stepper speed in half, but not make it stop. The home sensors, did nothing and wouldn't zero the PC's position display.

The Printer Port terms and software config are setup properly, but I just didn't want to rip apart the controller since I just got it all assembled into it's metal box. After consulting with Dave @ Buildyouridea.com, I opted to just leave it for now, Once I get this cutting foam, I'm pretty sure it'll be quite a while before I get bored of watching the machine run.

This is a dremel tool on steriods, 3/4 HP and lots of goodies. I originally thought that I'd use this to be the milling head, but it's overkill on this little machine.

The spindle can run at either 20,000 or 30,000 RPM. I assume it's a Roto-Zip Rebel knock-off OEM'd to Canadian Tire under the MasterCraft label. Regardless it gets quite a bit of use for free hand foam shaping.

The Next Mill will be designed around this unit, the spindle accepts 1/8" and 1/4" collets and bits.

This is what I finally settled on to run the spindle, a 12VDC encoder motor from one of the oldest CiTOH printers I've ever seen.

It had a gummed front bearing, and the brushes and commutator needed a good cleaning.

The 4 magnets and spring loaded brushes place this motor well above the typical low current DC motors I encounter.

While the motor was apart, I threaded the shaft to 5/16ths 18 TPI, drilled out a 3/16ths collet chuck and tapped it as well to 5/16ths #18.

Here they are screwed together for fit.

As per usual the drill press bored an angled hole that has the tip of the spindle defecting 1/16th inch I'm really bummed about this drill press as I can drill holes by eye that are truer.

After being reduced to using the blunt force of a hammer on such an imprecise surface as a concrete floor, it's actually running pretty true.

The spindle runs smooth, but at 12VDC, seemed just a bit sluggish. I checked on the Spec label on the back of the PC power supply, and it had a -12VDC line that was rated at 600ma.

I doubt this motor draws much unless stalled, so I tested the motor between the + and - 12VDC lines (effectively 24VDC)and it just sang.

Though I'm not big on wood working, it did seem to be the best choice for this portion of the project as I had some nice pine scraps from some home renovations we just completed..

As always there was a liberal amount of sitting and just positioning different sized pieces of wood around until I had a sense of how things would sit.

I used a 2 1/8 " hole saw on the 2 boards clamped together to get the best alignment.

After some cutting and sanding everything was snugged in nicely.

Of note is that the grain should be horizontal in the uprights or it will break if Vertical when tightening the motor in place.

Also I labeled the front, back, tops and bottoms to ensure that the spindle would plunge along a vertical line.

Here is everything bolted together. The pine would look nice with a clear coat of varnish, or I may prime it and get more Industrial Blue.

In looking back on the progress over the last few months I'm glad I've remained on track. Each block of time I can squeeze in has moved this further along. I'm hoping to be ready to cut some foam before next weekend.

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