I’m cutting 9mm ply with a 4mm 3 flute end mill at 0.5mm depth steps. I’ve tried cutting slowly at 600mm/min and fast at 1600mm/min and in both cases the cutter starts to chatter. I’ve just tried a new cutter and that’s the same. It’s particularly bad on the X-axis. I’ve checked all the wheels and everything is tight with no play. I’ve checked the tension on the belts too and they’re fine.
Which spindle are you running?
If you are running the Dewalt try it on 1 and use 3657mm/min.
I went back and read some of your posts and some of the issues you have had, is it possible that you have the stock spindle running backwards?
1 Like
Embarrassingly, your detective work is right but I corrected that a few weeks ago - it makes an amazing difference when it set to spin in the right direction !
I’m using the stock spindle which I understand spins at 12000rpm. Is that fast enough or should I consider an upgrade. I use routers which spin at 20k +
I have never used the stock spindle, so I am sorry I can’t help with feedrates and depth of cuts. I personally use the Dewalt and I am very pleased with it.
Out of curiosity…how does one check that, and what is the solution? 
Thanks.
I believe it is simply a matter of reversing the wires.
Symptoms are burning material (melting plastic), ragged edges, dulling of bits and general bad quality cuts.
With the stock spindle and 9mm ply with a 4mm 3 flute end mill at 0.5mm depth steps try 2743mm/min.
I have not heard any complaints from folks that upgraded to the Dewalt 611.
I feel like im good… but it should spin clockwise… right??
Yes, Clockwise.
Just swap the wires if it’s going anti-clockwise.
The new versions of X-carve are supplied with DeWalt now aren’t they? Can the spindle stop/start still be gcode controlled?
Is the collet on the DeWalt an ER11 like the standard stock spindle?
The DeWalt D26200 I understand is the equivalent uk model to the 611
No, it is not a standard ER-11 collet. And you can start and stop the Dewalt in g-code with the use of a relay.
The collet is interchangeable though isn’t it so I can use various shank sizes?
Make sure that your point of reference is correct. 
It comes with a 1/4" collet, I purchased a 1/8", 4mm and 6mm collet for mine from Elaire corp.
@ErikJenkins can you explain this a bit I’m curious how it works with the Dewalt. The use of a relay. I’ve been turning the Dewalt in by the switch on top this whole time.
See this post where I explained it…