I would like to know what people do to level Z across X.
I have found that I can be off several mm across the 4’ of my x axis.
I always park my lowrider on some cradles between jobs and then try to pre-tension the z lead screws on both sides before powering on but it is really hit and miss.
I have started dialing in level by turning the z lead screw on both sides and lifting the wheels off the table and then turning them back till the wheels just touch. Then I power on the machine.
Is there a better way to do this?
I’m wondering if it is worth rewiring my z motors so I can get separate control and then learning how to dial them in through the controller individually which is another can of worms.
I do the opposite. I turn the lead screws so the gantry lifts up a little, and let it settle back down before I turn on the motors. The lead screw and the motor shaft are touching inside the coupler, so forcing them to settle back down to touching seems to me to be the best way to get a consistent Z height.
I started doing it that way as well but it was hit or miss based on where the lead screw would stick. The left side of my x axis has more weight on it with the controller and vac hose.
Good to know that this is the standard procedure though.
Is is hard to get independent z motor control? I was reading about dual end stops and z probes and I looks like a lot.
If I just wired my z motors into both ports of the miniRambo ports does Marlin let me adjust them separately?
Nope. That is essentially wiring them in parallel, which you don’t want to do (it won’t break or anything, but it’s not as good as your serial wiring).
It’s a little tricky for the Low Rider, because you want to travel all the way down, and even rest the weight of the gantry on the bottom when it’s not running. So you can’t easily put the endstops on the bottom. So you need to set it up to home the Z up, which just adds a little bit of non-obvious configuration. What worked (I haven’t tried, but I worked with someone who did) was to wire one Zmax endstop to the Zmax port, and the other to the Ymax port, and then configure it to use those (and dual motors and dual endstops). There isn’t a preconfigured solution, so you’d be getting your hands dirty, but I can help if you want to try that.
I think this is another good place to focus. I wonder of something isn’t aligning right. Mine will gladly drop all the way to the bottom on both sides, even if the gantry is all the way in the middle. There’s no way I’m getting 4mm of slop in in coupler or lead screw. When the gantry is lifted, do you think the lead screw and motor shaft are touching? They should be. There are also several counts of putting the top part of the LR2 on backward, so the Z pipes don’t line up parallel. Something like that might be making it hard to sit all the way down.
Actually, you said you could turn the screws to lift the wheels. Does the 611 plate touch the spoil board when it’s all the way down? Maybe that’s the issue. Mine has enough clearance to still be floating and the gantry comes all the way down on both sides. If that’s the problem, then there are two simple solutions. First, you can move your rails up, if that’s possible. Second, there is a user created part to add a cradle for the gantry just above the spoil board. Just something to park each side on. I don’t know where the files are, but I know they were shared, I would just have to find them.
My lead screws are touching and the couplers are solid. I am using the cradle you are referring to (you can see it in the picture from my first post). I believe my z pipes are resting against the top notches as they should on all four points.
Mine drops all the way down without binding, it has just proved inconsistent to preload the z screws moving the gantry up when it comes to z level across x.
Since I changed to rotating the lead screws the opposite way to lift the wheel momentarily of the bed (gantry resting on cradel), the two sides have been much closer. I will probably just keep doing it this way for now.
Thanks for the thorough response and all your time!
I made some C shaped shims and clipped them around the Z pipes until the Z was level side to side across the whole table when disengaged. Then I just made my startup script run some gcode to move to a spot on the table where I drilled a hole and disengage the motors so it drops onto the shims and levels itself.
I got my table as level as possible by running a leveling program on the LR2. Each time I start it I zero my end mill on the table, check it in minimum X, then maximum X. I adjust the Z axis motors by hand as needed. I haven’t had any issues with that method. Where possible, I try to keep the machine on (Steppers engaged) while I swap out jobs.
