How much slop is acceptable on carriages.
February 06, 2019 02:27AM
Assembling my first printer, a Tevo Tarantula.

The rolling assemblies have these wheels with eccentric nuts that you turn
to move the wheels in and out to adjust closeness to the extrusions.

A few of mine don't seem to get close enough (snug enough) and I can actually
take the moving assembly and wiggle it a bit.

Is there any wiggle allowed .. or should it be pretty wiggle free, and if there should be
none, any suggestions on how to tighten mine up a bit.
Re: How much slop is acceptable on carriages.
February 06, 2019 06:48AM
Watch this video

[www.youtube.com]


Electronics Technician / Computer Programmer
Re: How much slop is acceptable on carriages.
February 06, 2019 07:13AM
It should be firm, but not no so hard as to damage the wheels.
Re: How much slop is acceptable on carriages.
February 06, 2019 08:23AM
You should not be able to wiggle it by hand. Anything tighter than that will deform the wheels though.


[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]
Re: How much slop is acceptable on carriages.
February 06, 2019 01:39PM
zero


Son of MegaMax 3D printer: [www.instructables.com]
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: How much slop is acceptable on carriages.
February 06, 2019 01:40PM
That video was the cat's meow ...

Thanks for the help everyone.

Mike
Re: How much slop is acceptable on carriages.
February 08, 2019 01:52PM
Just to finish the thread with what happened, I have a small home machine shop. I elongated the holes and
put spacers in. The one I did for the X carriage came out nice, but the ones I did for the bed carriage I messed
up and actually made it worse.

So, am awaiting the aluminum bed support from ebay.

Mike
Re: How much slop is acceptable on carriages.
February 08, 2019 04:44PM
I'm not sure the problem was there before your modifications. What I ran into with a cnc router was that the eccentric nuts were not formed well, it wasn't eccentric enough for many of the nuts so it would not be tight enough or too tight in some cases.
I ordered some proper ones and that resolved it for me.

As for tightness, the purpose of the 2020 slot and wheel system is to constrain movement in all axes except one. Ideally that means no movement in all other axes and in the axis it should move it should be able to as smooth and freely as possible. This is to ensure that no compliance/backlash occcurs due to belt stretching and other kinds of mechanical springiness.

It's also important that tge bearings in the wheels run very smoothly. If you feel any kind of slop or grinding you should replace them with better quality ones.

Edited 1 time(s). Last edit at 02/08/2019 04:45PM by imqqmi.


--
Kind regards
Imqqmi

NFAN CoreXY printer:
[reprap.org]
Re: How much slop is acceptable on carriages.
November 10, 2019 11:20AM
Some acrylic pieces may not have been cut with correct hole distances. On the Tarantula's X carriage, I added a new hole for an eccentric spacer center of the two original ones, but slightly closer to the rail. In order to do this, I gradually increased bit size from smallest such as to not crack the plate, then finished it with a needle file until the eccentric spacer fit. I was able to properly tighten the axis, now in a 3-wheel configuration.

Now to replace the terrible acrylic Y bed support plate...
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