# X Axis Jumps Back.Need Help!



## BrianSim (Sep 1, 2016)

Hello everyone, I could really use some help here. I received a CNC router after a dear family friend passed away. He built the router himself and unfortunately took most of his secrets with him. The original P.C. that was with it failed beyond repair so I had to find a new P.C. that was compatible to run with the control box he built. Looong story short I finally have all axis working in both directions. I'm using Mach 3 for my controller. The only problem I have left to solve is the X axis has two motors, one on each side of the gantry. It seems almost as if the left side motor is running faster than the right side motor and this causes the whole gantry to "jump" back after moving in + or - direction. It seems to be only "jumping" back on the left side. Like the left side is trying to pull that side faster and the right side is anchoring it in place so to say because its not moving at the same speed? I don't know if that's the problem or a better way to describe the issue but essentially that's my problem. It has been countless months getting this up and running again and I'm so close! Any help or input would be greatly appreciated! 

Thanks,
Brian


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## BrianSim (Sep 1, 2016)

Ok I just pulled both motors , put them side by side and confirmed the left side is spinning much faster than the right side. Anyone know how or where to adjust the settings for this??


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## difalkner (Jan 3, 2012)

I am just getting into the CNC world and building one but I believe the Y axis has two motors and X has but one. Are the two motors set the same way in Mach3? Are the motors identical? Do they connect to their own stepper driver and are those drivers the same with the same settings? 

That's where I would start my troubleshooting... 
David


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## bgriggs (Nov 26, 2008)

Briansim,

I would be glad to help you get your mach settings under control.

I suspect you have not properly slaved the motors together and/or one may be running in reverse. If not. Then it is probably just a matter of setting the acceleration and velocity for both motors to the same values.

I will send you a direct message with my Skype contact info if you like.

Bill


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## BrianSim (Sep 1, 2016)

David,

Thank you , 
I appreciate your thoughts on this. It almost appears that the X axis would have two motors and the Y one but indeed it is the opposite. When facing the machine as in the picture I posted the Y axis is actually the axis moving left to right. The users orientation/perspective is off 90 degrees when facing the machine this way. I've been doing CNC machining for 19 years now and believe me this drives me nuts being orientated this way but its just the way it was setup. The motors are all identical and they are all connected to their own stepper drivers. After reading thru many other post on here I got lucky and I found that if I went into the "Motor Tuning and Setup" and changed the Step Pulse from 0 to 5 it synced the two X axis motors to rotate at the same speed.


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## BrianSim (Sep 1, 2016)

Bill,

Thankyou! I could still absolutely use some more help on this. I believe I solved the original problem I had. After reading thru many other post on here I got lucky and I found that if I went into the "Motor Tuning and Setup" and changed the Step Pulse from 0 to 5 it synced the two X axis motors to rotate at the same speed. The two motors appear to be working in unison now. The problem I'm now having is the scale factor or "Steps Per" setting In "Motor tuning and setup" seems to be off. Ive found where I can try to calibrate each individual axis and tell it to move 2.00" per say and than key in how far it actually moved. Only problem is to precisely measure the distance it moves. I suppose I could bring home some dial indicators and whatnot but there must be formula to correctly figure out what the settings should be? Also it seems my Z axis is moving in the opposite direction I tell it to...Ugh, so close, yet so far.. lol

I'll set up a Skype account now, and reach out to you. Thank you for offering to help!

Brian


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## TwoSkies57 (Feb 23, 2009)

bgriggs said:


> Briansim,
> 
> I would be glad to help you get your mach settings under control.
> 
> ...


Always impressed with your willingness to assist other members Bill.... very cool indeed!!


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## honesttjohn (Feb 17, 2015)

Bill is good (and very busy) - so grab him when you got the chance.

HJ


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## bgriggs (Nov 26, 2008)

Thanks guys. We got Briansims sorted out. Let the dust Fly!

Bill


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## bgriggs (Nov 26, 2008)

Thanks John.


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## bgriggs (Nov 26, 2008)

Hey Brian. How did you make out? Problem solved or are you rewiring the axis?


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## BrianSim (Sep 1, 2016)

Bill,

Thanks again for spending your time on the phone with me to sort things out. It is truly appreciated and refreshing to find good people willing to help. I brought home some indicators and whatnot and calibrated all 3 axis in last night, I also added a variable speed control for the spindle. I tried to switch around where the wiring plugs in to the control box and slave the motors together how you showed me, but unfortunately it didn't work. It wanted to move 1 motor in X and 1 motor in Y at the same time. I'm guessing since it worked fine without having both motors slaved together that somewhere in the control box itself the hard wiring would need to be changed. I'm not sure I want to tackle that just yet and as much of a pain in the butt it is, I think I will just work with my axis being off 90 degrees (simply put) for now. I did manage to re assign my hot keys to work with the orientation of my table so that helps some. I will also most likely be ordering one of the 3 way edge finders we talked about. I see that as being an absolute must have considering my past working with these machines. Thanks again for everything! 

Brian


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## bgriggs (Nov 26, 2008)

Post some good quality pictures of the inside of your control box and I will take a look.

Bill


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## BrianSim (Sep 1, 2016)

Bill,
I just saw this post. Must have overlooked the email notification. I'll try an get some detailed pics up real soon here. 
Thanks again
Brian


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