Our components are M10 and work compatibly with each other and with 10mm holes.
Shade hole: +10mm
For holes larger than 10mm use washers sandwiched together to hold the 10mm cable clamp.
We sell washers here.
Cable clamps come with all thread and a screw to secure it. Here.
Use extentions to fix the lampholder in place.
Use this method for unusual holes.
