Board Measuring Accuracy

[Rbacak]

I'm getting ready to carve a jig that will hold 4 copies of the same project. I'm using 3/4 MDF and I checked to make sure it is square. I was going to let the machine measure the board and use those measurements in Designer for maximum accuracy. BUT...... I'm getting slightly different measurements and not sure if it's enough to worry about:

1st Attempt: W=10.018 L=17.051
2nd Attempt: W=10.017 L=17.057
3rd Attempt: W=10.018 L=17.044

Machine has about 35hrs, rubber belts and dust collection, about 86lbs head pressure. I did clean the board sensor before measuring.
I did recently replace the X-Gear assembly due to my own stupidity but I'm pretty sure I got that right.

Am I being overly critical?

Roger

[FWMiller]

I rarely get any better than that on mine.

[SteveNelson46]

Your measurements are normal tolerances of the machine.

[Digitalwoodshop]

Picture in your mind using a flashlight to measure the edge of a board and that is what the board sensor is doing... Shining LED Light on the board and when it goes off the edge of the board the reflected energy goes away.... Like shining a flashilght into the dark sky at night, you don't see any reflected light... Unless you place your hand out and shine the light on it... Same theory.... And that turns on a bit in the computer and a snapshot of where the encoder is at that moment gives you the measurement... So there is some "Fudge Factor"....

[FWMiller]

Plus, when the right end of the board gets to the board sensor it is off the brass roller. So for the last few inches of travel the machine has to make an "educated guess" on how far the board traveled before the edge sensor detects the edge.

[Rbacak]

Thanks for all the responses.... I figured it was just me being critical. I made the jig and it turned out perfect.. Now to cut some blanks to fit the jig and get back to having fun!

[Chip]

Roger,

To give you a reference for the differences that your machine came up with, an average hair is .003 inches in diameter. The width measurement did not vary but .001" - 1/3 the width of an average human hair! The length varied a little more, however the .013" difference between the second and third measurement is the width of only 4 human hairs. The machine is doing a fantastic job in my opinion.

Chip

[Rbacak]

Well when you put it like that I do feel overly critical! LOL!! I knew the differences wasn't that much but just wasn't sure if it might be indicating an issue or not. Of course I didn't think of it in hair perspective.