The Sieg X2 mini mill is known by many names. Grizzly G8689, Harbor freight 44991, little machine shop 3900, Micro mark 84630 as well as models formerly offered by Central tool, Homier and Cummins. They are all the same mill with a few small variations. The most important of which is whether it comes equiped with a R-8 or MT-3 spindle. The R-8 is the preferred spindle due to the fact that there is more and cheaper tooling available for it.
These are nice little mills for small work, right out of the box, but there is still a lot of room for improvement. The purpose of this thread is to discuss these mods. Searching the net I have found many great threads dedicated to hotrodding these mills. One of the best sites is Tooling, parts, and accessories for bench top machinists - LittleMachineShop.com
This site is all about mini mills and lathes. They offer a ton of reference material as well as stock and upgraded parts.
Reference - LittleMachineShop.com
I have ordered from them several times. great service and same day shipping