SK137 NIXIE TUBE SOCKET 3d PRINTABLE FILES DOWNLOAD HERE :-

heres where i got the socket pins :- https://www.pvelectronics.co.uk/index.php?main_page=index&cPath=4_11

the fit with a tiny bit of glue and a good squeeze, maybe carefully using a vice to push them in. once they are in. they aint coming out! and the spacing for the holes are perfect for the tube.