Progress on the CNC Wood Lathe Project
I’m not happy with the way the initial rails turned out for my CNC wood lathe-mill project. The long rails are held to the short cross-rails with screws and nuts and small L-brackets. I just can’t seem to get them to hold together as tightly as I would like, and I am afraid the vibration of the final machine will shake the screw/nut combinations apart too quickly.
So, I’ve scrapped the original design and I’ve begun making a new design for the side pieces of the railbed using plywood. I laminated the hardwood-plywood up to 1" thick, and then I used the hollow-chisel mortiser to cut 1" square openings for the long square rails. Seems like it will work, but we’ll see tonight. I’m still working out the best way to secure the rails to the plywood ends with the adjustable-accuracy and a minimum of movement that I want. I’m over-building the rails a bit because my plan is to modify John Kleinbauer’s design (after I have it working as John did) to allow for several different tools to ride on the tool-sled. Also, I intend to install a 3rd stepper motor on the lathe’s axis through the lathe’s hollow handwheel to allow for rotary motion. Will it work??? Maybe…I am sure it can be done, the question is whether "I" can do it. I’m a woodworker, not a machinist. Software to operate the rotary motion may be the hard part. Rube Goldberg, watch out!
I also made the anti-backlash nut according to John K’s instructions, and I really like his design. It is simple, sturdy and I think it will work very well. I made it out of the plastic from an old router table insert that I had laying around that doesn’t fit my current router table. The antibacklash-nut is ready to be mounted to the rail assembly as soon as I complete the new rails.
The stepper motors and Economy FET-3 controller board arrived from Stepperworld.com over the weekend and the parts look good. Now I need to get the old computer that I have stored somewhere in the basement functional again to drive it. According to all I have read, any old computer will do, no real computing power needed. This is good, because the old computer that I intend to use is at least 8 years old, maybe more. It hasn’t even been turned on in at least 3 years.
To keep them straight in my head, I’m calling the CNC Lathe attachment that I am currently making the "Mark 2" as the "Mark 1" was the machine that I built last year with unsatisfactory results (too much vibration and wiggle in the cutter head). The "Mark 1" was not CNC, it used a fixed template for guidance. The "Mark 2" is largely a clone of John K’s Wood Turtle CNC. After I have the Mark 2 operational to the point that John K took it, I will build a new tool sled for it of my own design. This will be the "Mark 3" and is my ultimate goal.