Bed leveling looking for some feedback.

[Mrclaybo]

Looking for some feedback. Been having a hell of a time trying to level the bed. Originally did it the steps as described and never could get a good bed level. After reading several post on this forum ( all of them..lol) I decided to do a little more measuring. I removed the onyx board and snow flake. The snow flake measures flat with a straight edge. But the onyx has a rise in the middle even cooled. I know it can flex when hot but it looks like I’m starting at a slight disadvantage.

I then measured the Borosilicate glass. It too has a slight wave in it on one edge. just sitting not clamped down. ( I think I need to call SEEmeCNC and see if this is expected or maybe i got a dud..lol )

Next i used calipers and measured every spacer and all 6 spacers were different thicknesses ranging from 3.85 to 4.2. Luckily the guys at SeemeCNC sent plenty. I measured everyone and got 6 of the exactly 4mm and 6 at 3.85. the other had no more than 3 that were the same thickness.

So I put the machine back together with the glass on the onyx board clipped in three spaces evenly apart. Heated bed to 90c and head to 225c. I don't really like the paper method since I have a hard time feeling if the paper is close to the same on all three test points. My solution I pulled out feeler gages and my smallest is.2mm

Since I has the bed somewhat level to before I decided to start at the X tower and test. With the new spacers in height was off. So i moved the height till the .2mm gage would just slide under ( .25mm will not). Then I measured and adjusted the other 2 towers the same. All are exactly .2mm. I checked these 3 times each and all measured right.

Moved to the middle and middle measured out at .33mm. So started to mess with the offset. kept adjusting but the middle did not move After offsetting +5mm I decided to check a tower and oops , head was resting on the glass so I reset offset to 0 and checked all towers again. Still at .2mm. ( didn't mention before but I home between each measurement. )

As I adjusted -1 I noticed the middle did not lower but the towers rose up but higher than .33mm. So I made a quick chart with XYZC down the left and offsets across the chart as I changed them. With the height measurements under each offset, for each point. Dialed into -.57. Now all 4 points measure out at exactly .3mm.

It was 1am so I will pick up this evening and run the Rostock Onyx Bed leveling Aid from thingiverse to see if I still have the flattened spots in the same place or not.


But to this point does my 1am logic sound good for leveling?

[Jimustanguitar]

I did this adjustment dance over the weekend. You need to get your build platform straight first. After that, my advice would be to create a custom G-Code script to test the 3 towers (it gets tedious to manually position the thing over and over). But don't worry about the center yet. Get the 3 towers perfectly level with each other first. Check your center height only after the outside 3 points are repeatably accurate. If the center is high or low compared to the 3 outside points, you need to adjust your delta-radius/smooth-rod-offset in the firmware until you get all 4 to be exactly the same.

After tweaking this a handful of times, I had all 4 points dragging very evenly on the same piece of paper and I updated my script to run all 4 points for future checks.

It sounds like you're measuring in the right ballpark for accuracy here. The bed leveling doesn't need to be accurate to the hundredth or thousandth because, after the first layer it's all up to the arms and steppers to make it accurate