I picked up an IKEA Grundtal knife holder at Goodwill. Got it home and promptly dropped one of the spacers from the package. It went bounding off in some non-eculidean direction never to be seen again. But hey, what have I got a 3d printer for? After determining that the spacer was non-ferrous, I grabbed my calipers, opened OpenSCAD, and I'm good to go again.I wrote the openSCAD file for the "perfect printer," which is to say, if your printer prints slightly large or small, you'll have to account for that yourself. Not that it should matter, this thing is not a precision part. Make it about 15mm across and about 10mm high and nothing else matters.