MakerGear Forum

I'm using a dial indicator and I get all corners equal, but when the dial indicator is at the middle of the bed the number is different. I'm kind of new to this any help or just point me in the right direction it will be appreciated greatly.

I suspect you have a slight bow in your x-axis rail. I don't know what causes this. I would not expect it to be actually bent, but just the combination of the off-center belt tension and the length of the top plates is just enough to create a slight bow in the structure. I had this on my printer. I measured across the plate at every bolt location, extrapolated the curve up to the bolts I could not reach, and added shims at each bolt location across the length of the x-axis rail. I can now get a consistent first layer edge-to-edge.

You have a shim-set recommendation?

insta wrote:You have a shim-set recommendation?

I bought plastic sheet shim stock from McMaster - .001" & .005" thicknesses.
I used a paper cutter to make a bunch of itty-bitty pieces 12mm (or is it 10mm - the width of the rail) x 2mm, if I recall. I put equal stacks on each side of every screw. I oiled the top of the plate a bit so the shims would stay put.

Huh ... no concerns the plastic will creep over time? I know Jim shimmed his with brass.

insta wrote:Huh ... no concerns the plastic will creep over time? I know Jim shimmed his with brass.

It's rated at 200F - and clamped between metal bits that won't get any hotter than the ambient - even in a hot box it should be fine, IMHO.

At work (where I use the M2), we have a couple of $$$ Zeiss Prismo CMMs. They're basically built out of granite blocks - the table, the Y axis - and ceramic - the X and Z axes. When you pull off a cover on the base you'll find a giant iron triangle supporting it all.....

Which leads me to pose this about the M2: 3 points define a plane, not 4. So why 4 adjustments on the bed? I can certainly bend the glass with the adjusters. There ought to be two in front and one in the back, in the middle.

peterbrown77 wrote:Which leads me to pose this about the M2: 3 points define a plane, not 4. So why 4 adjustments on the bed? I can certainly bend the glass with the adjusters. There ought to be two in front and one in the back, in the middle.

If the bed were as rigid and guaranteed flat as a block of granite, that would work well. The older M2 models had a 3-point bed support. Having used both, I'll take 4 screws.

Noticed how you can bend each corner up enough with the slight touch of the corner adjustment tool to tighten your hold on adjustment shim? I suspect your dial indicator is putting pressure on the corners enough to throw off your measurements. Mine did.

Put the dial indicator away and use a .005" .127mm feeler gauge. No need to get that technical and precise. Been there, done that. Level it once without the corner glass holders putting much if any pressure on the glass. When you remove your prints, remove the glass.

I reset my level about 10 prints ago and it still adheres and prints first layer just fine. Set it and forget it.

86bg wrote:Put the dial indicator away and use a .005" .127mm feeler gauge. No need to get that technical and precise. Been there, done that.

Glad that works for you, but i had a .012" bow on my X rail. It was not possible to get the first layer consistent from edge to edge of the bed.