So - after a very long delay, I've finally finished my JGRO router, and have made some wood chips with some very good results.

I'm using:
* HobbyCnc Pro board with their 305 oz-in steppers
* 1/2" 10 TPI ACME screws/nuts - I'm using a little "liquid graphite" for lubrication.
* DumpsterCNC anti-backlash leadnuts
* HDPE – I used ¾” HDPE cutting board pieces for the adjustment blocks
* 1" Gas pipe for X & Y axis & 1/2 Gas pipe for Z. The plans called for 1” only on the Y axis
* 3 piece LoveJoy Couplers
* Barrel nuts etc. - NO tapping or screwing into any MDF parts.
* LinuxCNC Controller Software (was EMC2 when I started building...)
* VcarvePro - trial version
* Ryobi 1/4" laminate trimmer

After I finally got my head wrapped around the various stepper configs, coordinate systems and offsets, I was able to cut the "Bulls Head" demo from the VcarvePro SW.
Besides reminding me that I have to "surface" my bed surface, the V-carving showed some "chatter" - where it looked like the bit was bouncing a little as it went along.
I didn't loose any steps, and the areas that had a "final" pass performed (because they were deeper ?), came out very good.

I'm thinking that this might be one of the following potential problems:
* Even though I'm using the DumpsterCNC anti-backlash leadnuts - There still may be some in the system.
* The machine is not rigid enough, and really is bouncing...
* The laminate trimmer is underpowered, and the bit is being pushed through the material (3/4" MDF) faster than it is being cut.
* I'm trying to take off too much with each pass
* The router bit I'm using is not carbide - it is new, but I've used it in the CNC while I was adjusting it.

My first question is "what are your thoughts" on the cause of the chatter?
It seems from the build threads that regular (heavy) routers are being used by others - so I'd also like to know if the JGRO with the 305 oz-in steppers is capable of lifting a router.
Or - should I not even be having this problem... beacause the laminate trimmer should be adequate?

Thanks for any input...