Small 4in1 Spool Holder

thingiverse

Here is what i think would be good sizes for 1/4-28 nuts: Human beings tend to like precision when it comes to their things. Hence, four measurements seem ideal - 52mm, 48mm, and also 38mm & 32mm could work quite well indeed. Feel free to print one set that has just 608 bearings on them since these are often preferred, or even the flanged kind if you happen to have those as well. Adding more options later is not entirely ruled out though. It depends really how it goes or whether someone else actually asks for specific spools in particular sizes, which hasn't happened so far.