How much deflection to expect...

[Wal]

Hi all,

Yep, I know the right answer is zero, but with home-built machines I guess we need to be a little realistic.

I mounted my z-axis yesterday, here it is:



No doubt it'll be on and off a few times more for shimming etc, but while I was at it, I torqued it all up and out of interest measured the deflection at the nose of the spindle with the z near it's downward limit. Pulling hard on the plate that the spindle is mounted to, my dial gauge read 0.05mm. Is that any good?

Vid here:



It's on TBR20 supported rails, how big an improvement would I see with profile rails?

Cheers!

Wal.