Toe in problem?

Hello again.

Just had a situation where the stepper motor on the Z axis started hopping/chattering.

Went and had a look closely at the side of the table and the thing looks like it has either come undone/moved or I have not done it properly and it may be rubbing.

See these photos.

The black plastic is touching the Z axis stainless pipe in some of them.

I have fiddled around tightening/and loosening things but it seems to me that if I pull out on the bottom of the Z MDF piece ie put my fingers on bottom and pull out it all lines up better.

So, does that sort of imply that the X axis should be loosened ie the outermost top nuts and bolts and push the tops closer in towards the center or am I totally lost here…?

I also see the MDF has bent when I put a ruler to it? See last photo…

Puzzed Rob

You’re missing bearings on the top piece. There should be a third bearing on the long bolt where your finger is on the first photo.

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So funny… I wondered why they were left over… Groan.
Back to the drawing board.

Thank you so much

R

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Ok, fixed that. Took a bit of fiddling but my other question remains.

The MDF pieces are clearly bending. We have had a lot of humidity here of late, ie heavy rain and I wonder if that is not the problem.

Should I recut them out of marine ply or even ply and aluminium as a sort of sandwich?

R

Yep. Not necessarily humidity related it’s super dry here and I have the same issue.
I recut mine out of 1/2" baltic birch but I’m thinking 3/4" would be even better.

OK, will do the same.

Thanks mate

R

I would say try just turning them around. Without that third bearing you put a lot more torque on them then normal. Flipping them should clear you up.

Thanks for the tip.
How does this sound for an idea?
1.take them off and lay them flat under a weight for a day or so.
2. epoxy a layer of fibreglass cloth on one side ie add about 1.5mm to thickness.
3.tidy edges
4.light sand
5. turn around and reassemble?

I do feel an idiot for staring at the leftover bearings and wondering why they were there.

R

I would try just turning them around. Worst case you put it together and cut a new set.

There is some tendency to flex a little even with the bearing so if you turn them around it might cancel out and give you something perfectly level!

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Well as we are now under lock and key here in the colonies and are looking for activities I have redone the Y Plates from a piece of marine ply with 4 layers of glass cloth epoxied to it.


New photos at the end.
I have reassembled it pretty much and will finish it off tonight. It is now sooooo stiff it is not funny.
Hope you all stay safe from this virus.
Thanks for the help again.

Rob

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