Resonating spindle gallery

I’m cutting a 430mm circle from 24mm ply using 1/8" end mill with 0.25mm passes and feed speed of 2000mm. I use the stock spindle running at 12000rpm
The problem I’m experiencing is the motor and the gantry it’s attached to begin to resonate when it’s cutting in the -Y direction. It does resonate a bit in the -X direction too but not as much. When I say resonate, I mean I can actually see the whole thing vibrating.
I’ve tried changing depth and speed but it doesn’t really help much.
I’ve checked the whole machine over in great detail and as far as I can see everything is adjusted correctly. I adjusted the voltage to the Y steppers yesterday to make sure the motors aren’t cutting out under load - they seem fine.

I’m really at a loss to why this is happening.
Any suggested would be greatly appreciated.

Have you done the x axis stiffening mod?

I was experiencing something similar when i first got my machine. As the bit would travel in the y axis the bit would encounter variations in the wood grain and the x axis maker slide would torque or twist and release in time with the grain density.

After I did the stiffy mod, (a bit intimidating but not difficult) this was resolved.

I am not sure what the spindle may or may not have on what you are experiencing but my stock spindle crapped the bed about the same time as when I did the mod and I went to a 48 volt quiet cut and again no more issue with twist or torquing.

Thanks, I’m glad I’m not alone. I’ve not done the stiffening mod, the x-carve is just as standard.
Where can I find details of the stiffening mod?
Also, the quiet cut spindle. Is that the Inventables one?

I would suggest starting here for one of at least two stiffening mods:

That one is totally reversible with no drilling required.

The other option is this one:

Requires drilling and more expensive hardware.

What’s a 800W GMT spindle?
I’m getting the unbearable chatter from the stock spindle too - it’s horrible!

Just looked up GMT spindle on Google. They look very nice but only available is USA? I doubt they’re available in the UK - can’t buy anything in the UK.

Carried out the stiffening mod and it’s got rid of 90% or the resonating. Just need to upgrade the spindle and I think I’m there.

Good to hear that. Which mod did you end up going with?

I used the simple one. The bolts in the gap between the maker slides. A quick visit to the hardware shop, 10 mins of fitting and it’s a lot better. Just got to get rid of the screeching stock spindle now.
Looking at this one.

You’ve got the GMT spindle which looks great but I can’t find one in the UK. I assume you control the speed manually through the VFD rather than through G-Code so your GMT is the same principle as this eBay model. Not the same build quality I would guess but it may do the job. Any views on this one on eBay?

I remember reading some people buying the ones of Ebay, and I don’t recall hearing anything negative about them. Hopefully someone who has one will chime in and give you some feedback. I’ve been looking for an air cooled spindle and VFD for a while now…just waiting on saving up enough $$ to buy one.

Ive got the inventables quiet cut spindle. I also had to go witha 48 volt power supply to run it and added a speed controller as well. I run the 24 v supply to feed the steppers and control the on/off of the spindle manually.

Ordered the eBay spindle today. I’ll report back next week when I’ve got it installed.

I have the spindle shown above… so far no problems at all!

I love mine and I have put it through some serious work in the last few weeks.

Fingers crossed you should have the same experience.


Mine arrived Monday and I tried it for the first time last night. I think it’s great too. Only thing I have to sort out is to redirect the downdraft away from the work so it doesn’t blow dust everywhere. I little job for my 3D printer.
How did you mount the spindle?

If it’s the 65mm spindle, you can purchase the dewalt 611 mount from inventables and put a shim between the mount and spindle (I think some people used thin sheet of styrene or even aluminum). That’s the route I am going to go whenever I purchase a new spindle/vfd.

I printed one. It works OK but there is a little bit of flex in the mounting plate so I think the final version will be a combination of an aluminium back plate and a 3D printed spindle holder.

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That looks nice! Is your new spindle a lot heavier than your old one?

Yes. I only had the 300W stock spindle before which was just a tiny motor. The old spindle weighs 0.5kg and the new one 2.3kg

Simon. Have you done anything clever with the control of it? I notice on the VFD that it has various connections so that it can be controlled remotely rather than using the buttons on the control panel.

Clinton, the only thing I have done so far is wire up a potentiometer to the vfd to adjust the rpm easier… although it is not that hard with the original faceplate controls. I have also toyed with the idea of installing a switch away from the vfd. Are you planning to operate it remotely via your software… I’d be interested in hearing about it!

I mounted mine use the inventables Dewalt mount (shimmed with some 3mm adhesive foam), works like a treat. I’ve attached a pic below.