Gatton CNC?

[Ben Helmich]

Hello,
I'm thinking about doing a Gatton CNC machine. I like the idea of buying the parts as I go as to not affect the household budget too much. It is a plywood machine that looks like most use NEMA 23 motors on. I have some questions:

1) What kind of surface finish do CNC routers leave? Would there be a lot of sanding to do?

2) How fast would this thing cut with the NEMA 23 motors? Could the plywood frame even handle the bigger motors and feed rates?

3) What kind of accuracy would something like this produce? Would it cut as straight as my table saw?

4) What am I missing here? I'm obviously new to CNC. I envision using it for cabinet panels, 3D carving, signs, intricate curves, dadoes, etc. It seems like it handles some router table functions. I HATE routers. They are noisy and scary. It seems like a CNC with a spindle would be quieter. And safer because I wouldn't have to hold the machine with the spinning death bits in my hands. And maybe I could do something else while it works.

Looking for a less expensive way to learn something new and expand my capabilities.
Thanks!

[David Buchhauser]

Here is a video review of one of the Gatton machines. My takeaway is that the reviewer is satisfied with his purchase and build. There are other reviews that you might consider taking a look at if you are serious about building this machine.
David
https://www.youtube.com/watch?v=nQnPLv1az38

[Bill George]

Ben there is nothing scary about using a router motor on a CNC, lots of machines have them. I have a Hitachi 12 something on mine not that noisy. I built and just finishing up a made in China kit WorkBee and there is a Facebook group you can check out. I went with PMDX USB made in USA controller and its control software is Mach4. I will probably upgrade the stepper drivers to Leadshine also.

Before building a plywood CNC you might look at the used market. I just sold a steel framed machine in wonderful condition used for more than likely what its going to cost you to build a Gatton.

[David Buchhauser]

Just curious. Why did you sell such a nice machine?
David

[Richard Gonzalez]

There does seem to be a lot of satisfied users, but almost everyone likes what they are invested in, otherwise they would be fools to have invested (confirmation bias). My only issue with it is that the electronics kits he recommends seems to have poorly matched steppers/drivers. If you do a little homework and setup your own electronics you will get better performance. Buy low inductance steppers, and use a drive voltage close to V = 32 x sqrt(inductance). Low inductance steppers have less torque drop off as rpms increase. Hint: No available Nema23 steppers operate at peak efficiency at 24 or 36V.
Also, highly recommend against a Mach3 controller (even the company that developed Mach3 recommend not using it for new builds). Use Mach4, UCCNC, Acorn/Mosaic or Linuxcnc, all are more modern and supported. Mach3 has not been updated since 2012 and never will be in future.

[David Buchhauser]

Great advise, but probably "over the head" of the first time buyer.
David

[Ben Helmich]

So you size the power supply voltage to the stepper motor inductance? His reccomended have an inductance of 5mH. Using your formula yields 71V. Did I understand you correctly? What mH is considered low inductance? What would the lower inductance motors with a better matched driver do for me? I mean, what would that really mean when the machine is in operation? Speed? Smoothness? Accuracy? I'm sorry to be pestering you with questions, this is very new to me. If I can make it a little better to start with and save frustration later it would be better.
Thanks, Ben

[Bill George]

Ben that is for a professional use everyday machine and speed is king. For a hobby machine it will be just fine if its not perfect but it will still work. You can certainly do the research and find a low inductance motor in a NEMA 23, the Steppers Online drivers made by Leadshine are good stepper drivers. Steppers Online I think also sell motors.?

The formula above is for Max Voltage.