Billy Bookcase 4mm Extension

If you're like me and annoyed that the BILLY bookcase (and extension unit) is 4mm too narrow to fit exactly three full-width modular houses side-by-side… be frustrated no more!

This is a set of parts forming a 5mm extension to widen the bookcase just enough that you can fit those models for display!

Most parts should be printed twice as I split the design in half for smaller printers like the Mini, and you will use two for each side (see photos).  PETG recommended, PLA will deform and crack under stress over time. 

There are multiple parts:

• Extender_Top_Bottom - For the top and bottom of the BILLY and the extension top. Two per “position” and side, so print EIGHT for one BILLY, or FOUR of the pre-sliced G-code as it contains two already. 
• Extender_Extension - For the back panel of the extension unit. Two per side, so FOUR total. Sliced g-code has two on a plate already. Not required for base unit.
• Extender_Toekick - For the lower front of the bookcase. One per side, two total. G-code has two. 
• Extender_Shelf - Small spacers so the shelf holders are spaced correctly. Slip them over the shelf holder and then install it in the side of the cabinet. Four per shelf, pre-sliced g-code has four. 
• Replacement Shelf Brackets (Courtesy of @invaderzim_1535382). These are all-in-one brackets that do not rely on the original shelf pegs, since apparently there are different versions of BILLY with different hole sizes. Of course, you should evaluate the suitability of a fully plastic 3D printed shelf bracket for your usage and take care not to put on too much weight :) 

Disassemble your bookcase, and remove those tall screws and insert under the screw as shown. Reassemble. 

(Note - As this alters the structure of the bookcase, I would not recommend putting anything heavier than LEGO models on it. The usual disclaimers apply, modify your unit at your own risk and evaluate suitability of this mod for your application before using. I am not liable for any damages resulting from the use of these printed parts or modification. )