Chattering on super sized x-cave

Anyone got an idea what might be causing this chattering, wheels and belts are both tight nothing is loose, has me stumped

Is that a Microcarve Z axis? If so I had the same kind of behaviour before I replaced the oilite bushings.

Not really, although mine were held in with epoxy which was a surprise. I got what I could out/softened with a heat gun and then “pressed” them out using a long M10 socket cap bolt (the head was a perfect size to press the bushings out but still fit in the hole for the bushings) and a socket with washers and a nut on the back.

I cleaned out all of the old epoxy and found the new bushings were a very loose fit in the bushing/spindle mounting block (I had expected to have to press the new ones in as well before I started all of this).
So, I slid the bushings onto the linear shafts and put the z axis back together. I then applied epoxy to the bushings and pushed them into the bushing block. I oiled the shafts well beforehand to avoid any epoxy sticking to them.
Then I added a little more epoxy into the four holes on the back of the bushing block (on mine these were covered with some strange black stuff almost like melted plastic, and filled with epoxy). I had the bushing block mounted in reverse for this so I could fill the holes from the front and lie it on its back to cure.

As far as the actual size of the bushings, I’m afraid I don’t know the dimensions. I gave them to an engineer friend as he had loads of various sizes, and he gave me four replacements.

My Z axis has been fine since being rebuilt, but I was very disappointed when I discovered a bucket load of epoxy was involved. I guess that is why the guy that made them told other users the bushings were not replaceable.
I certainly would not buy another one from him

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not a microcarve (i think) but very similar, bushing seems fine. problem only showed up recently

  1. check gear belt gear on the x-axis to see if it is slipping just a bit.

  2. clean the rail for dust buildup…

  3. also looks like there is a power issue … are you using to Arduino with motor shield. if the potentiometers are not adjusted right they can sometimes do that… as well as overheating of the board.

nothings slipping, have cleaned dust made no difference, have turned down the power doesn’t seem to have made a difference, will turn it down more and see ho it goes

I am still running a first generation machine with the old style x axis rail with a stiffening mod and a linear z very similar to yours.
I had some y travel chatter that was all but eliminated with a short strut made from some flat stock and placed between the back top “lip” of the x carriage and angled at about 45 deg. up to a point near the top of the linear z. I can get some pics if that helps and I think Phil has done this as well, perhaps he’ll chime in.

The chatter in x travel suggests to me v-wheel adjustment but I could be wrong.

chatter is on both x and y but is a lot more evident on the x axis, v wheels have been adjusted many times with no change at all, oh a photo would be good thanks

If you get hold of the collet or the bottom of the router can you wiggle it slightly? This is where I discovered the source of my chatter and ultimately that my bushings needed replaced.
I’m not talking about loads of slop either, just not rock solid

yeah they have a lot more play there then I would like, but I haven’t got a clue where to even begin looking for replacements so I may end up replacing the entire z axis instead

thing is the chatter exists even when carving air so I think the main problem lies else wheres

nothing i do seems to have any positive affect, it now keeps losing steps and nothing I do even stops that now

losing steps seems to be caused by the the stepper motors being able to move to easily when they should have a strong resistance to being pushed in the wrong direction no matter how much power i give it it just doesn’t seem to have enough to over come the resistance of the timber and when not cutting I can push the x axis back and forth way to easily, anyone know how to solve this

What are you using to drive the system? Have you measured the voltage drop across your cables to see if there’s a problem? It should be minimal but that could indicate a wiring issue.

v wheels seem fine pots are turned to max

using x controller voltage seems fine

If you have the pots turned to max, it may be your issue.
My thought is that even when simply holding things in place the g shield (assuming it’s a gshield) is going in and out of thermal overload/shut down.

Try backing the pots off to about 60% of max or check out the vids here on the forum on how to set them and run it again. Your problem may go away.

have set the pots to many different power levels nothing has made any difference so far

It was worth a shot…