Thread: X3 backlash videos

I'm very much a newbie at this, so I'm looking forward to any feedback which moves me forwards along the learning path...

I've been playing with getting my mill to draw circles - (pencil in chuck), because I found it easier to spot any bumps or niggles where the axes change direction.

So far, I've found:

1) the Y-axis nut was a bit loose, because the mounting bolts were just a tad too long (or the X3 casting was of variable depth).

2) if you lock the Z-axis gib, and have the mill hanging most of its weight from an engine hoist, the head doesn't move down properly - that was a "Yikes!!!" moment!

3) stepper motors drive the axes back and forth quite merrily, even when the gibs are tight enough to make it a drama to move them by hand. (I was experimenting, and have slackened the gibs a touch)

4) common hardware washers are stamped out, and so have a raised edge on one side. These aren't even all the way around, and when you have a few stacked up, the height of the stack can vary depending on the rotation of individual washers. Fixed that with a few minutes rubbing the washers on a diamond plate.

Anyway, now that my circles were looking good, I did some tests using a dial indicator.

I zeroed the dial indicator touching a clamp on the table, then jogged away, and used G0 to move back to the zero position. When X and Y were looking OK individually, I used G02 and G03 to do a 3/4 circle away and back.

Videos are at:
https://picasaweb.google.com/arose62...eat=directlink

As a beginner, I *think* this is looking good, but have I missed anything significant?
Is there any standard procedure for measuring backlash?

Other pics and videos of my beginner CNC playing are at:
https://picasaweb.google.com/arose62...eat=directlink

Cheers,
Andrew