Off .125"

[gibl5s]

After changing ALL of the gears on the motors and setting up a new spoil board , I ran a test run with a V bit and found out it is off around 1/8 where ever I send it and also when it returns to home. I have a 4x8 standard w/spindle. I need tighter tolerances!!
Anyone else experienced this?
Thanks so much

[dlcw]

X, Y and Z are all off by .125?

[gibl5s]

Thanks for your concern. Just the x&y are off. I simply cut a groove in the X & Y and put some Baltic birch in it to make a fence. Then to see how accurate the machine operates I took a board 8x8 and laid out 2" points ALL over it. After telling it to go to (Y2 X2) it would be off close to .125. Surely this is tighter than that.

[srwtlc]

Are the new gears the same tooth count as the old gears? After putting the new spoilboard on did you reset your offsets to the prox switches for the homing routine, in case the new spoilboard isn't in exactly the same location as before? Are the motors adjusted into the racks properly? Better measuring method would be to clamp a block up against one side of the gantry, zero out there and move 1,2, etc. and measure the now gap between the block and gantry.

[tlempicke]

Sounds suspiciously like you are measuring to one side of a quarter inch bit. Put an engraving bit or a very small sharp V bit in the spindle. Do a C3. Use the bit to engrave a .020 deep line in the X axis. Move the Y axis to +10 and do the same thing. When you measure the distance it will be off by 10X the distance of error per inch.
You should be abel to achieve .002 repeatability using the C3 move.

[jerry_stanek]

Try this file that Gary Campbell has to square the table it also tells how to change the distance

[bill.young]

I'm assuming this is a new behavior that has appeared since changing the pinions?

Is the error always 1/8"? For instance if you go 6" it's off by 1/8", and if you go 60" it's still only off by 1/8"? Or is it progressive..if you go twice the distance then the error is double?

If it's always the same error no matter the move length, then I would be suspicious of the pinions being loose. Maybe the set screws weren't quite on the flats when you tightened them, and they spin a little during direction changes?