Bee Frame spacer - 22mm wide frames, gives a 11.75mm space between frames

thingiverse

This is a spacer that fits over a wooden bee frame, which means straight National frames typically used with castellated spacers then have Hoffman spacing - very nearly 1 and 3/8 inches. Precisely, these added to 22mm (Straight National) frames give 33.8mm spacing where Hoffman is 34.9mm (Hoffman 34.9 does not include clearance which you will need). These spacers have four holes at 1.2mm down each side for conveniently adding pins to hold the plastic to the frame. The chamfer version has two millimeter holes plus a chamfer to bring the heads of some pins inside the plastic so they don't catch on neighboring frames.