Level in corners ... but not in middle, where most gets printed

[terrypin]

I spend a lot of time on bed leveling the glass bed of my Ender 3 V2, using a piece of inkjet printer paper so that there's some friction at each corner. But there always remains a slightly larger gap in the middle. It's also visible if I place a steel ruler across, with a light behind. Not much, about the paper's thickness, gradually decreasing on each side, but presumably enough to cause trouble?

I eventually persuaded Creality to ship me a replacement but after a couple of months I've concluded that's the same, so must be a general problem?

Q1: Do others (with any bed) have same issue?

Q2: Why are most leveling instructions focused on the corners, where very little filament gets placed?

Q3: Given that all my prints are quite small ( typically a footprint of under 100mm square, and often half that), should I always shift the model in the slicer (Cura in my case) from its central default to near the front left corner?

To get as much feedback as possible on this long standing vexation I've also posted in Reddit's Ender 3 category. I hope that's OK?

https://www.reddit.com/r/ender3/comments/oqn70i/level_in_corners_but_not_in_middle_where_most/

Terry

 

[terrypin]

Thanks for all the helpful replies.

For now, I'm trying kitchen foil. bltouch sounds a bit too complicated, and one more thing to maintain. If I ever treat myself to a second 3D printer I will be in the market for a ready-to-run model with fully automatic leveling. Is there one yet on sale at a hobbyist price?