Tiddy CNC.

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Originally Posted by TonyD

[...] thoroughly cleaned the rest of the rail with degreasant and elbow grease. The rail came out really clean, the bearing I had removed ran rock solid and smooth over the rail and once bolted back in the gantry is noticeably smoother. I'll do the other side next day or so. I have already got the right type of grease for future lubrication

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Just to be sure, did you put any grease or oil in the bearing before testing again and finding it to be 'smooth'? If not, then (at risk of stating the obvious) do put some in before going further as running without any lubricant (which is presumably the case if you've cleaned it thoroughly) even for a short time will reduce the life of the bearing. Hard to say by how much, but there's no need to risk it.

Edit: You might want to check the ballnuts for debris whilst you're at it.

Thanks Jonathan, I havent moved it much at all but now the other side is done too I am much happier with how smoothly it moves. Thankfully I didnt oil the ball screws at the time so the residue isnt on them. I'll grease it all up again soon. Tony.

Move to Go. Do not pass Go.
OK, so I'm about back to where I was before, when I was racking the machine and trying to bend the ball screw out of true. I've got the machine moving smoothly and I'm setting up homing prior to figuring out the limits and setting the soft limits and I've hit a snag, done some reading to avoid wasting the time of people and I'm not confident yet.

Problem is dual X axis homing, Z homes OK, Y homes OK, when I select X home, (thankfully at 2% speed) the maching starts to rack as one X axis motor is turning, the other isnt. The weird thing is that under jog movement they both move together, so now I'm into the Mach ports/pins and homing screens. Ports and pins I have X and B axis configured correctly I believe, they move on jog so I'm OK with that, Z,Y,X Home I have values and the diagnostics page in Mach confirms they work and Y and Z home OK anyway. I *do not* have a home input signal for the B Axis as I assumed that as its slaved to my X axis that would be OK, clearly its not so I suspect I need to add input signal values for the B Axis and copy the X Axis home port and pin setting to fool mach into seeing the same switch? Is that the answer? as always advice appreciated, thanks.

Tony. I am off to bed now and had a small drink. But in the morning if nobody has responded I will check my Mach3 and let you know the settings for it. You need two homing switches as the way it works is that both motors should drive the axis back to the home position then one switch trips and backs off then the other does the same. Its also important to have exactly the same setup in motor tuning for both the motors. When it works it will work fine. ..Clive

Thanks Clive, for now I only have one homing switch, can I/do I have to use the inputs for one home switch for both home inputs?

Tony you MUST have 2 switches on separate inputs for homing to work with slaved motors. The first switch can be wired in series with Y & Z but the second must be on it's own input.

Also in General Config you must UNCHECK "home slave with master axis"

Thanks. I guess I need to figure out a way to mount the switches on both sides with enough adjustment they both connect at the same time.

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Originally Posted by TonyD

Thanks. I guess I need to figure out a way to mount the switches on both sides with enough adjustment they both connect at the same time.

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Tony Jazzcnc hit the nail on the head I could not think straight last night. If you pm me your number I will run through the settings with you.
If you are worried about racking when testing take the belts or motors off both sides then you can see what is happening. ..Clive

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Originally Posted by Clive S

Tony Jazzcnc hit the nail on the head I could not think straight last night.

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Alcholic Pisshead syndrome. . .:very_drunk:

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Originally Posted by TonyD

Thanks. I guess I need to figure out a way to mount the switches on both sides with enough adjustment they both connect at the same time.

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Tony if you use the bullet type proximity switches they have a threaded body which you can use for adjustment. Also if using proximity switches you can use the sensing distance as kind of fine tuning which is handy for setting slaved motors.

Finally, auto home on all axis - thanks for the help. For the help of others, although as Jazz says the dual input was required and I didnt have that to start with, once I wired that up I still didnt have the dual X axis home working. I was about to write a detailed post here with all my Mach config settings when I noticed a discrepancy between the various B or A axis settings, once they were all pointing to the same B axis it worked. Happy days :)