X Axis Travel Accuracy

Pl7i92 has rosen a good point. Is the x axis independent from travel distance? I gues that happens.
If yes, you have to look for backlash. For this you should read
linuxcnc.org/docs/2.7/html/config/ini-config.html chapter 2.11.......
BACKLASH = 0.0000 - Backlash is in machine units. Backlash compensation can be used to make..........
If it is distance related then you have to do scaling. But sorry, I do only direct editing in the hal file.
SCALE = 1909.8 is your candidate to modify in [AXIS-0]
Good luck
Mike

Hi Mike,

The problem is distance related. If I manually tell the X axis to move 6" it only moves 5" and 31/32". It does that every time too.

I can't feel or see any backlash in this R&P system. With the machine powered up and a dial indicator on the axis the machine holds very solid when I attempt to move the X axis. I need to check the scale of the dial but I'm sure it only moves the needle +/- 0.001"

I'll have a play around with the scale but it does my head in a little why the Y axis is bang on in distance travelled with identical settings and R&P system.

Cheers,
Jason.

Could you have accidentally been shipped a metric unit?

5mm and 3/16 are close enough by eye but only get noticed with an indicator untill you get into long distances

They only have two options and both are imperial. 1/4" (20 Teeth pinion) and 3/8" (22 teeth pinion).

When I swapped the steppers it was just the motor and small pulley on the motor. Not the big pulley with pinion.

Cheers,
Jason.

Sometimes i'm very pragmatic...
And change scale..

Thanks Mike,

I’ll give it a go and see how she goes. Effectively I’ll be calibrating the axis. Must have been a fluke the Y axis came out right. The gantry axis was the one I expected to cause pain but it was the easiest...

Cheers,
Jason.