This is an adaption of LeandraChristine´s spool holder (http://www.thingiverse.com/thing:572674) which does not use screws to hold the two halfs of the sliding tray together. Instead, you glue two of the 4mm thick cutouts that are the same shape as the ends of the tray together and sandwich them between the two sides of the tray. The bearings just slide right in. To be made out of 4mm material. Note: The picture does not use the cutout pieces, instead i used some scrap wood as spacers. I will make another one next week or so using the lasercut pieces.