Kossel 2020 foot

Feet to put on the bottom of the towers of a 2020 Kossel 3D printer, to keep the horizontal extrusions off the bench and ensure that the weight is taken by the corners. They also provide clearance to attach a metal sheet to the underside of the extrusions, which I use to support the power supply, heated bed SSR and mains distribution terminal block (see https://miscsolutions.wordpress.com/2015/06/01/building-a-large-delta-printer/). They attach to the underside of the vertical extrusion using an