cnc crashes when cutting 2D profiles in wood

[magicniner]

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0.5in spindle:
having a larger collet will help vibrations as far as the advice I've been given goes... the chinese spindles i have seen only have a 0.5in n a 2.5Kw spindle. this is whole lot bigger than the 700w router I am using... but it would also be heavier and would just add to problems with the current machine.

The only thing a larger spindle can do for you is add mass, there is no magic in spindle capacity itself which can reduce vibration, only mass and rigidity will do that.
You can experiment with added mass with your existing spindle, there will be a sweet spot for each set of cutting conditions but more mass will always give some improvement as it's inertia will resist cutter deflection.

Looking at your video again your spindle mounting system could be massively improved by adding a second identical mounting ring and having the two as far apart as possible, your current mounting arrangement has almost no triangulation and will be a point of flex in the system.

[cropwell]

Have a look on t'interweb for 'toggle clamps'. Ebay sell shitloads from China. Also have a look at this kit from Chronos - Soba M6 Clamping Kit 36 pc (Ref: 120710).

I will have a look at your spindle mounting and get back to the thread. I have significantly bolstered up my spindle mounting, but it just shows everything else wobbles in my Dicey machine. Is there such a thing as engineering viagra? (Just to stiffen everything up).

OK back again : Your spindle mount has a couple of threaded holes doing nothing (is this the same on the other side?) You could probably put in some triangulation there to clamp to the Z axis plate.

Rob-T