Initial Design Check Please

[JAZZCNC]

Are these the right kind of thing? Only reason im asking is there seems to be different versions ie HGR MGN.

Sorry about all the questions.

Hi Trev,

No problem with questions that's why we are here to help each other and ask questions. Don't stop asking questions no mattter how daft they may feel, if your not sure ask.!!

Regards the rails and bearings then like eddy says 20mm tend to be a better size and not just for greasing, they make building the Z axis easier due to being taller and generally give better support with there larger bearings. The rails also sit on the profile better.
With the type then look on the Hi-win site and it will show the difference between the types, it's often very subtle differences like hole centres or bearing heights ratings etc.
Most use the HGH-CA for the slim type and the HGH-CW for the flanged wide type with standard pre-load Z0. If your wondering what pre-load means then it's the amount of pre-tensioning the bearings have when on the rails. Pre-loading removes any slop or play but at same time requires more force to make the bearings slide so we don't want it too high. Z0 is lower pre-load.
Those new to using profiled linear rails are often shocked to find that the bearings don't easily slide when on the rails but require a good shove and then stop quickly. This preload at work. Stand on the buggers and you'll end up on your arse as they work best under pressure and glide like on ice. .. Lol

If your buying from Ali express the look for Fred Lee. Personally I buy ballscrews and rails etc from from Chai at linear motion bearings but he doesn't sell Hi-win brand of rails, they are some other Taiwanese brand which can't think of at minute but they are very good quality do just the same job and a little cheaper.