Printer: Creality Eccentric

The stock Creality extruder side v-slot wheel eccentric is an eccentric only on one side and just a regular spacer on the other. This not only means the wheel move in a cone shape instead of just in/out, it also means the two outside wheels ALSO slightly move in a cone shape. So you end up with the wheels riding slightly cocked to one side in the extrusion.

 

Stock setup.

So I drilled out plate with a 9/32" drill bit and added a second eccentric in place of the spacer. If you don't use a drill press or mill, a step drill bit should do a good job of keeping it centered. I marked the spacers with one divot on the short side and two divots on the long side, so I can easily see which direction they're facing. I now need to manually keep the two eccentrics synced up, but that's not really a problem, and it's much better than stock setup. The adjustment is much more predictable now, and I can get all the play out with the wheels still relatively loose. 

 

Dual marked eccentrics.

 

Printer: Applying PEI Sheet

Almost all PEI sheets use 3M 486MP adhesive (transfer tape) to glue them to the bed. Most methods involve a dry application where you roll the adhesive on while slowly squeezing bubbles out. Regardless of how well you do it, you'll still end up with tiny bubbles. If you get a bigger bubble it will bulge up when the bed is heated. Plus, 486MP is incredibly tenacious stuff, and if you apply it even a little wrong there's no way to recover from it.

The solution is doing a wet install. 3M doesn't officially recommend it, but it works well. You want to mix 1 litter of water with 3 drops of liquid dish soap and put it in a sprayer. Clean the bed well, then liberally spray it down with the water. Peel the back off the 486MP and liberally spray it down with water as well. Then roll it onto the bed, and squeegeeing the water out from under as you go; I usually use a credit card. Then put it between two flat surfaces, put some weight on top, and let it sit for two days.

If the 486MP didn't come pre-applied on the PEI sheet,  repeat the previous steps to glue the PEI to the adhesive installed on the bed, and sandwich it again for two days.