Tramming the M3

[friolator]

Ok, so I have a 1" surfacing bit and surfaced my spoilboard this afternoon. Obviously from the picture below, the Z axis is slightly out of plumb, possibly in both directions (you can see a bit in the beginning of the Y cuts near the back of the photo. 




My questions are:

1) What's the best way to tram the M3? This is actually a lot better than it looked at first. I loosened the four screws that hold the X axis crossbar to the frame and slightly twisted it until things looked square (using a small woodworking square), but that doesn't seem like a very precise method. 

2) Does this level of imprecision matter that much if I'll mostly be cutting with 1/4" or smaller diameter bits? I'm mostly concerned about this with aluminum, when I get to that.

Thanks! 

[Derek the Admin]

It's best to make it as plum as you can. When the router is out of plum it will affect things like inlays a lot, for instance.

I'd suggest laying a machinist's square or speed square on the bed then comparing the vertical portion to the body of the router from a distance with one eye closed. Do that from the side, and then do that from the front. That ought to get you very close.

[friolator]

Hi Derek,

That's what I'm doing to check it, however, what is the correct way to adjust the position? Rotating the X-axis support? What about rotating the router on the Z-axis?

The adjustments I've made are obviously too crude, so I'm wondering if I'm missing some trick to hitting the sweet spot. It'd be great if the router could have some kind of fine-tuning adjustments using a screw or something, to rotate the Z-axis in both directions, and really dial it in. 

Thanks!

[Derek the Admin]

I see. There's unfortunately no adjustment like that. Having something like that would necessitate some other trade offs, but I digress.

Think about looking at the machine from the front. If the router is tilting forward or back then rotating the X rails is the way to adjust it. You can use the speed square to get it pretty close, where you put one side to the bed and the other side of the square to the X rail. That will get it pretty close, but I'd still use the method discussed earlier. If the router is tilted left or right then that adjustment is only on the router mount; as in how it's mounted to the Z plate).

[friolator]

Thanks. What actually worked best was putting a small level on the spindle mount. The bed is pretty much close to level (probably a bit off because of the floor or the work bench) so I matched what i saw there with the spindle mount and this is the result. Not bad:



Two other minor issues I hit: One is that the Y homing switch has a small screw on the switch body that was contacting a screw on the plates under the bed. This caused the whole bed to jump a bit at the end of the Y passes, which I think is what caused the scalloping at the back of the spoilboard:



That's actually much better than it was before that last pass. I'll need to go a bit deeper, but need to adjust my spoilboard size first in FreeCAD, because, oops:

[Derek the Admin]

Looks good though. You can push the Y switch bracket ever so slightly to get rid of that bumping.

I almost forgot to mention to you to check out the “training the spindle on the cheap” sticky. That’s a good one to reference.

[friolator]

Sept 8, 2018 3:38:51 GMT Derek the Admin said:

I almost forgot to mention to you to check out the “training the spindle on the cheap” sticky. That’s a good one to reference.

Thanks. Yeah I saw that and I think I'm going to make a bracket that holds my digital dial indicator at the far end from the spindle. May as well quantify things while I'm at it!

I'm pretty happy with this as it stands right now. Going in tomorrow morning to try to run the first project on it.