For the CNC router to act on a part in the rotary axis, the lathe would have to sit far too low for manual use. To use my lathe as a rotary axis and for manual turning, I would need a stand with built-in height adjustment. This became a major hold up in my upgrade plan. I thought of several ways to adjust the height but none were really practical or cost effective.
I discovered the website woodgears.ca which has some really interesting and well engineered projects. One of the items I found there was a wooden gear generator program. Actually there are two different programs, one is free and is used for creating paper gear templates. The other is a reasonably priced program that can export files to be used in CAM software for CNC. I finally had a solution for my lift system. I purchased the gear generator program and went to work.
The first set of gears was cut from 1/2-inch birch plywood from a home center. Later I cut a second set of gears from Baltic birch after one of the small ones began to fail because of an internal void. The rest appeared to be holding up pretty well.
I also cut four racks to match.
I used 1/2-inch cold rolled rod for the shafts then cross drilled for roll pins. I used the CNC in manual mode to make the slots in each gear.
The base and the top are torsion boxes so there will be minimum sag over the five-foot length. I used the router table as a reference surface to assemble the boxes and make sure they were flat.
This stand was built like the router stand on a slightly smaller scale. I also used the same four-inch dual locking casters.
Business end of the lift system.
And now, some video.
Some of the parts after a couple coats of urethane.
I used two 6-inch carriage bolts along with turnbuckles to hold the lathe on the cabinet.
I bent the hook on the turnbuckles to catch the cross bracing under the lathe bed.
The turnbuckle hooked over the cross member under the lathe bed.
Threaded rod to pull the two cabinets together and lock them into a single unit.
The plywood spacer block is needed to allow the wooden wing nut to spin without hitting the cabinet until I add the final trim to the front of the torsion box.
The fourth-axis stand and lathe, fastened to the router stand. The lathe stand is in the lowered position.
Here you can see that the router can travel beyond the center-line of the lathe. This could be handy if I ever get a spindle that will run slow enough for a flap sander.