Hi All -

About 3 years ago I started building a CNC router. Used it for just a little while and quickly embarked on an upgrade. The upgraded version turned out pretty well. Very accurate. Not perfect but good enough to learn on as I have no machining experience. Its rack and pinion drive on the X and Y and a ballscrew linear actuator for the Z and NEMA 23 steppers all around . I used a lot of parts from CNC Routerparts.com, NEMA 23 motors, their PRO motor mounts, rack mounts for the rack and pinion gear and a few other things. I used off the shelf parts in critical areas where I felt that my skills were only marginal and the better solution already existed. Just had to pay the man. I built the homing and limit switches for it from the thread on here and that turned out well.

I've done a few things for people now and one of those was for the local Boy Scout troupe. They were building kayaks and each kayak had about 12 frames for the structure. I think there were about 12 kayaks in total so this involved a lot of parts but a lot of repetition. Perfect for a CNC router. The job went very well and I was glad I could contribute.

So my friend is a incredibly talented woodworker and his son was one of the Scouts and he liked my router. About a year later, his wife approached me discretely and asked if I could build one for him for his 50th birthday. I had learned a lot since building my first one and I wanted to build another one but I didnt need one or have room for it. But I would love to build one for a friend I jumped at the chance. So this will be the chronicle of my 2nd build. I'm open to suggestions so share them if you have them.

Design goals:

1 - Reliability. This is going to get turned over to someone else. It has to be user friendly and it has to be stone cold reliable.

2 - Speed. Time is money. The faster it works, the more time it can be used. My friend is a busy guy.

3 - Precision. I would like it to be able to hold +/- .005" when machining hardwoods. Not sure if this is unrealistic but I think I can get it rigid enough to achieve this.


General design information:


I want the cutting envelope to be 6ft in the Y and 4 ft X, with 6" of travel for the Z.

The Z will be able to travel outside of the cutting envelope in the X plane. Mostly for touch reference probing off the bed.

No sidewalls on the cutting bed. Nothing for the tool collide with and this makes the workpiece more accessible and easy to fixture.

Motivation will be NEMA 34 ClearPath Servo drives on the X and Y and a NEMA 23 on the Z. Sevo's over steppers so no lost steps.

Machine base will be welded steel.

Machine frame 8020 T-slot extrusion.

Profile linear rails and Hiwin or THK bearings on the X and Y.
Rack and pinion drive for the X and Y

UCCNC for motion control as this is what I'm using now and MACH 4 seems to be unrefined(?). UCCNC works fairly well. And I can explain how to use it to my friend when this is delivered.

For a BOB Lots of options. Was considering the Leadshine drive from CNC router parts but the Clearpath Servo's only need step and direction commands. Not sure yet. Any suggestions??

More to follow

Pic is of my first CNC router after upgrade cutting out the kayak parts.