Based on Spool Spacer for M3D by Loswave (http://www.thingiverse.com/thing:753630). Thanks @Loswave! Description by Loswave: "This is a spacer for http://www.thingiverse.com/thing:705345. Print 2 and put one in either side of the spool. It acts as a bushing and gains a little more clearance between the spool and printer. It also prevents the spool from cocking to one side or another." I broke the above-mentioned spacer twice when removing from a spool, so I made a more robust version. The radius is also increased a little, so it has a tighter fit. I noticed the spools have differing inner radii, so please let me know if you encounter a case where the spacer sits too tight and can't be removed without breaking it. Downside: it prints a little longer than Loswaves spacer. Can be used with the excellent "M3D Mounted Spool Holder" (http://www.thingiverse.com/thing:705345). This can be seen in one of the photos. EDIT: just uploaded spacer_v4.stl. It has a thicker upper rim. EDIT2: removed ...v3.stl since v4 is better EDIT3: just uploaded spacer_v4_final_r1.585 and spacer_v4_final_r1.59 with larger diameter. (Radius ~ 1.585 cm and 1.59 cm respectively). I test-printed the 1.585 version and it fits tightly in my larger spools. Printing with PLA on the M3D Micro, I needed no raft and no wave bonding. Used "ultra low quality" and "medium fill". Another print with low fill was also good enough, maybe not as robust. (EDIT: I might have used "low quality" for the prints in the photo. Just printed on with "ultra low" and the base was constructed differently: not using concentric circles, but 2 circles with diagonal filling) Tip when removing from a spool: if the spacer sits pretty tight, turn it slightly while pulling. This reduces the danger of breakage (happened to me once, although with an earlier version).