Summary

Replace two parts in X-axis extension thing 215294 to make use of the increased Y-axis travel of the Y-axis extension thing 229854. Includes built-in bed-leveling adjustment - without springs! (see instructions for details)

Instructions

PARTS REQUIRED

TOOLS

INSTRUCTIONS

NOTE - author has only tested models with KISSlicer

print parts - these parts will NOT print on the original simple in the 100x100 configuration. You can print on simple with original bed with X-axis extension thing 215294
finish parts by drilling out 8mm and 2.5mm holes. The 2.5mm is the top front hole and the only bottom hole

... following assume you have already installed x-axis thing....

lossen belt tensioner, remove bed, then remove all parts from rods - save right end
Slide the left end onto the rods. If it doesn't go use heat gun to warm it up enough to go on. Make sure rods are fully inserted.
Slide right support onto rods. Again warm to get it to go
replace original right end support
slide belt into left support. Again warm up and "open" clamp if you need clearance then warm up and squeeze shut with plyers to clamp the belt
Thread the front screw through the bed support (top) until it is resting on the rod support (bottom). Put the back screw through the top clearance hole and start in the thread on the bottom but do not tighten
cut the aluminum bar so you have two pieces that fit between the left end and the right support
notch the back corners of the aluminum sheet as shown in picture to give clearance for the screw heads. Note this thing does NOT print to the edge of the bed so this will not reduce print area
apply and trim the double-sided mounting tape to the parts and the bars as shown in the picture, remove top green tap
place sheet on parts without bars. The press the bars under the sheet at the edges

Leveling the bed

move the hotend over the front rod (not the front edge) on the left side of the bed. Set Z to be "just above the bed"
move to the back edge of the bed then adjust the front screw to lift the bed to be the same amount of "just above" as previous step. Once you have a position loosely tighten the back screw so that the bed doesn't lift if you push down on the front end
repeat for right side