Continuing on with the build, I've run into my first head scratcher. I'm suspecting one of the parts milled by Avid was done wrong, but I'm not entirely sure yet - very well could be user error. I'm building the first legs of the gantry and attaching the bearing block plates to the vertical 80x80mm riser. There are countersinks in the block plate and you're supposed to use M8x20mm socket head fasteners to their roll in nuts.
My problem is that the fasteners bottom out inside of the 80x80 extrusion well before the plate is attached to the extrusion. There's at least 2-3mm of wiggle room. Tightening the fasteners anymore is just going to deform the extrusion.
For those following along, I'm on step 2.1.1 - Riser plate assembly in the instructions -
https://www.avidcnc.com/support/inst...8/20.2/risers/ (Tightening is done in step 2.1.2.5).
I grabbed 2 pictures of the problem, one showing the obvious gap even with tight fasteners:
IMG_1959.jpg
And then a second showing the inside of the extrusion. You can see I'm already making marks due to the fasteners that are too long for this application.
IMG_1961.jpg
First thing I checked to see that I have the right fasteners and I do. They're M8x20's. Second I checked the roll in nuts and they're right as well (although I don't see how that could resolve this problem). I don't see any notes about shimming the risers and I imagine that would cause all kinds of rigidity issues.
My suspicion is that the riser plate had the counterbores for the screws drilled too deep. I've watched a bunch of videos of assembly and mine looks deeper than others - but it's really hard to tell from screen shots:
IMG_1962.jpg
Other than that - I'm not sure what else could be wrong. It's still very possibly user error.
My correction thoughts are:
Be impatient - go to ACE and get some M8x15 socket head cap screws. Avid includes 12.9 fasteners and I think my ACE has those as well (it's a great ACE).
Be impatient idea 2 - go to ACE and get washers to shim under the screw head - basically reduce the counterbore.
Wait and see what Avid says (I'm contacting them now).
Anybody see anything obvious that I'm doing wrong. Avid's not exactly the quickest to reply and they're open M-F, so I'm blocked until next weekend unless I'm doing something obviously wrong.