I found running the "flat" surface of the focuser tube on a whetstone/sharpening stone improved the weight capabilities of my focuser. I generally followed this guide. It's a slow process but worthwhile:
https://agenaastro.com/optimizing-yo...d-focuser.html
and this is good for the general assembly of crayford focusers (screw number and placement seem to vary between manufacturers):
https://teleskop-austria.at/informat...rd_focuser.pdf