How to (easily) square the table?

I have the auxiliary tapped table for my Nomad3, and I’m trying to make sure it’s square to my axes. There’s a bit of play in the way it bolts to the main table, so it’s on me to ensure it’s square when those 5 bolts are tightened.

I’m using a dial indicator to watch the edge of the plate as I tram from -Y to +Y, and I’m seeing about 0.08mm of run out across the entire length of Y travel. So I obviously know that I need to nudge the plate a tiny bit to make everything square. It’s easy to do, but hard to get right.

Here’s my question: 0.08mm isn’t much “by hand” but it’s important for my double-sided milling purposes. I’m finding it really tedious to try to tap the plate over that small amount, and re-tighten the mounting screws without nudging it again. Has anyone found a slick means of doing this? For instance, some sort of screw-drive adjustment to nudge it in a controlled manner?

Follow-up Q: I’m assuming that by checking runout along the side of this plate, I’m also getting an accurate read on the position of the tapped holes in the plate? Those are what I’m really using for alignment.


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If the edges are square to the holes, how about a dowel in the spindle? Touch off to your first corner and snug the closest screw. then move to the next corner & touch the plate to the dowel & snug the closest screw to that corner. Go back & check the starting corner, adjust if necessary, and then tighten all the screws.

I like countersunk (tapered) screws for this as they tend to center themselves.

Another choice would be to machine dowel holes in the plates, and in the rails they mount to.

If your holes & edges were machined in the same setup, they should be as accurate as the machine is.

Thanks - this is helpful. I’m taking pretty good measurements with my dial indicator, and when aligning the dowel in the chuck to the holes in the plate, it seems to agree. But when I flip a part and mill the second side, I’m seeing a small offset - about 0.18mm or 0.007". Not much, but I’d like to get rid of it if possible, because it will make final finishing faster.

So with 0.007" offset, I have something like 0.0035" misalignment to go. Any idea of a practical way to take that out of the system? I suppose I can jog 3 mils and then re-zero, but that will move my entire X axis. If I have runout, I’ll need to nudge either the front or back that tiny amount.

Any ideas how to do that in a controlled manner?

If you flipped the part, and now the same edge is off, assuming you are certain you are flipping it and aligning it the same, It sounds like the machine is a little out of square.

To fine tune my machine (HDM) I first dialed in the steps per mm by cutting a large square (6" x 6") and measuring it and adjusting the GRBL $100-102.
Then I cut a diamond shape (A square rotated 45°) and checked the 2 diagonal dimensions and adjusted my left Y axis until they were the same.

Not sure mechanically how this is done on the Nomad compared to the HDM. I removed the stepper motor and turned the ball screw to align them. I placed an indicator on the carriage & calculated the distance I needed to move to square it up & turned the ballscrew to move the carriage that distance.
It took me a couple iterations to get it dialed in tight. I got it into about ± 0.003" over the entire work envelope.


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