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Author Topic: Backlash Variation  (Read 1942 times)

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Backlash Variation
« on: September 15, 2013, 03:25:31 PM »
Guys im really banging my head trying to understand why I keep getting such a variation when setting up my backlash. I understand the process and I know Im doing it correctly.
Let me back up the other afternoon I was making a circle with my CNC. It cam out oval almost egg shaped.  Did some reading and most suggestions were that your backlash is off. That made allot of sense at the time. Ok I already did my backlash but I figured I would do it again.
So I proceed .run the table backwards set to 0 g0x.010 look at the dial and it says .007 I have 3 thousandth backlash do it again to verify I tried .300 cam back .296 on my dail then tried .800 comes back .7935 on my dial . Every time I put in a larger number a larger percentage of backlash comes back . Now that may not seem like much but over the distance of the whole table it will be.
BUT ..
This was the real kicker when I took all the back lash out of the table and proceeded to go forward it read a number higher than what I went . If I start at 0 enter in .010 I would get back .012 or .0115
Ive dissembled my whole mill tightened up my half nuts did everything I could think of even swapped From a DDI to a DI to a TDI all the me stuff .  

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Re: Backlash Variation
« Reply #1 on: September 15, 2013, 04:09:13 PM »
Are your steps per unit set correctly?
Disable backlash and check them and check for Backlash with Backlash disabled as well as trying with it eneabled will not work.
Re: Backlash Variation
« Reply #2 on: September 15, 2013, 07:57:05 PM »
I got it with in .0005
It involved stetting the mpg to .0001 and a mechanical stethoscope.
I guess you have to take into account the DI / TDI reputability .