This is my first post. I've just joined and I've been wanting for some time to build a router lathe.

I believe starting with a actual woodturning lathe is a bit overkill. I'm thinking that the need to accurately control angle is probably the most important thing if you want to do something that is not a solid of revolution. Consider the problem of carving a totem pole.

I like Trend's router lathe but it pretty much make spiral cuts from what I can tell looking at pictures of it on the web. Still, I'd like to have one. Perhaps that's the kind of lathe you could start with. What do you guys think?

Does anyone have good source of gear motors preferably with an encoder on the motor shaft? Do the ones with encoders tend to have them on the geared down output or on the motor output? I'd like to find one that has the encoder on the back of the motor drive shaft. It would give me more precision for controlling angle.

I was looking at adding this as an xtra axis on my table.

Basically, you want to step the rotation as a router passes up/down the length. That way you can carve any pattern into the piece. So it's a three axis machine, rotation, position and depth.

First, I'd better finish my table.

That reminds me of this 3-d router duplicator machine.
http://www.terrco.com/index.php?page_name=duplicarver
It looks like 5 degrees of freedom.

What kind of motor are you looking for? Stepper? Servo?

If you do not want the turning feature (spindle) but just the C axis, then you can pick up a Bayside or Alpha Gear planetary, low backlash gearbox off ebay, Often with motor/encoder included.
Al.

Here is my 4 axis indexer that will do up to 24" by 10'. Probably a lot larger than you want. I have 6K invested in it.
http://www.turningaround.org/4_axis_mill.htm