After leveling my K1 build plate with Bed Shims designed by @NeedItMakeIt, I wondered if I could improve the sags between the front and side corners of the build plate. I realize its a potentially small improvement, but it may help with printing larger models.

The additional parts needed are a 4-40 x ¾" pan head screw, a 4mm OD, 0.4mm wire size, 10mm free length compression spring, and a 4-40 tap and tap handle. All of these are available on our favorite jungle web site. 

One of the tricky parts of assembly is turning the small threaded collar into the recess in the bed leveler body. A picture shows this being done with the tip of an Exacto knife. The other tricky step is applying a droplet of CA glue between the screw threads and the collar. The collar must rotate in place with the knob threads and should not be glued to the bed leveler body. The function of the collar is to keep the adjusting knob from moving in or out of the bed leveler body.

The slider block with give about 1mm total upward travel of the top of the bed leveler. (Up is counter clockwise rotation of the knob). It does not need to be adjusted beyond snug to have a very noticeable affect on bed leveling. Typically you would need at least 3 bed levelers to get the result I show - one in front and one on each side.