hand held controllers vs computer key board etc.

1) hand held controllers often directly connect to the motor controller to allow manual motion. This is handy if you have a large, say 4×8, CNC. You can walk to the end and manually tweak your origin points, etc. A PC keyboard cord usually won’t stretch 8’ and you can sometime mis-hit a control key with unexpected results. The pendant is normally in addition to rather in place of the PC keyboard.

2) depends on how tight your vertical positioning needs to be. If you’re running a laser or thru cutting vertical accuracy isn’t required. If you’re doing variable depth cutting the Z-axis ball screw is required.

3) water cooled needs cooling water. To save on water most shops use a recirculating chiller – an extra cost not normally included with the base CNC.

Now I have a 24×36 3500mw laser now. Used to have (for work) a similar sized wood cutting CNC that used a porter cable 693 power head with a solid carbide single spur spiral upcut bit cutting 6061 aircraft aluminum. We used a slow feed rate and a water misting coolant/cutting lube system. It cut alum like cheese.

-- The hump with the stump and the pump!

Pendants are used for manual control of the CNC, not for programming. They’re nice to have but not a necessity. We use wireless keyboards on our CNC routers rather than spend money on pendants. The operator can bring the keyboard to the machine, set the bit position then return the the PC to set the axis to zero. This works because our controller software is Kmotion and it allows us to set hotkeys for important functions.

Ballscrew vs rack and pinion will be a never-ending debate. Ballscrews have less backlash but cost more. They’re also prone to flexing and whipping if they’re too long and are spinning fast. That’s why a lot of manufacturers use rack and pinion on the X. Other companies will increase the diameter of the ballscrew to prevent whipping (more cost) or fix the screw and rotate the nut (Shop Sabre does this).

All of our routers have rack and pinion for the X. It kept cost down and they work fine as long as they are kept clean and greased. Backlash is minor enough that we still get plus or minus .005” without doing any compensation. For the rare job that requires extreme precision we’ll run a test cut, measure, then make manual adjustments to the cutting file.

Water-cooled spindles cost less and they require a water pump to circulate water through them. Some people use aquarium pumps. We use air-cooled spindles for convenience. The fans make a lot of noise but that doesn’t matter once the bit starts cutting wood. That’s much louder.

In my opinion, the biggest difference in entry level machines lies in the controller software. See if you can find a way to try test the software interface for the machine you want to buy.

-- See my work at http://altaredesign.com

So what machines are folks using here? CAmaster seems to be popular on the Creek.

-- BontzSawWorks.net

We run custom or retrofitted routers. One was built in a CNC-building class at Marc Adams School. It’s been rebuilt with a new vacuum bed and gantry and will be used as a vinyl cutter as soon as we make a new plenum for it. That one runs on Mach3.

Second is a 2000 era AXYZ 4008 with the motors and controller replaced with a Kmotion and encoded stepper setup from Carl Bruce. It has a cheap, Chinese air-cooled spindle that needs replacing every 18 months or so.

Third one is a 3×10 built from scratch by Carl Bruce. That uses ballscrews for the Y and Z and helical racks for the X and has a 5HP air-cooled spindle with auto toolchange. It runs on a Kmotion controller which works well paired with encoded steppers. The encoders track the position of the machine and correct errors on the fly if a motor loses steps and starts to get out of position.

Kmotion is a great controller for our shop because almost every aspect of the CNC can be customized in C programs and I know how to code.

If I were in the market for a small machine in the 7-14k range, I’d buy one from Carl Bruce if he’s still making them. Encoded steppers are nice to have if you don’t have the budget for servos and I don’t know of any manufacturers using them. Dollar for dollar, his 3×10 machine packed more features than anything else we could get for the same money. Biggest downside was a longer waiting period.

Does Powermatic make CNC routers or do they buy them and paint them yellow? I’m not sure on that but whichever route you go, I’d recommend buying from a company that makes the machines and isn’t just importing and rebranding.

A client of ours has a Shop Sabre and he’s happy with it.

-- See my work at http://altaredesign.com

Thank you. The thought process and debate continues. :):)

-- BontzSawWorks.net

You can narrow down the choices a lot by starting with the work you’re doing and going backwards to find a machine that is optimized for that work.

For example:

I’m guessing cutting saw handle blanks from 1” thick solid wood is a major reason for wanting CNC? The fine points on saw handles are prone to chipping if cut in multiple passes so single pass cutting is a big plus. 3HP minimum spindle for that with 5HP being recommended. A lot of people recommend more than 5HP for solid wood but that runs up the cost for any shop that’s not wired for 3phase so 5HP is a good compromise.

Bleed-through vacuum tables won’t hold small, solid wood parts very well. Vacuum pods might not work either for small parts like saw handles. So a T-slot table with slots aligned along the Y would be more useful to hold down boards while parts are cut with tabs to keep them in place. Most manufacturers align slots with the X for some reason. We glued and screwed slatwall panel to our solid wood machine to create the Y-aligned t slots. Strips of 1/4” MDF glued to the top of the slat panel act as sacrificial boards.

-- See my work at http://altaredesign.com