im in the process of building a 500x500 sphinx with the use of mgn15 rails and the blue ox plate set im at the stage of the build of installing and aligning the y axis rails it consists of two rails and 4 bearing blocks i have reached out and a few people have helped but im still having trouble i used an indicator to get the top rail aligned and then loosely bolted the y axis plate and moved back and fourth tightening the bottom rail but as soon as i tighten the bearing blocks down it moves but is very "choppy" not smooth and the noise the bearings make isnt very good i did clean and grease all rails and bearing before install im guessing it needs to be shimmed maybe between the block and the y plate ive tried that and all types of configuration to no avail any help is greatly apreciated thank you
I may not be understanding correctly. Did you align one rail with the dial, put both sets of blocks on, slide the plate on both rails and tighten the second rail as you moved the plate? Or was one, or both set of blocks loose while you aligned the second rail. If they were loose then there is no way to tell if the rail was aligned because there is too much play in all components. I would put the blocks on the plate tight. Make sure the aligned rail is tight. Put the second rail on tight enough to hold it in place. Slide the plate on with both sets of blocks. Push it past the first rail screw of the non-aligned rail.. Tighten it. Then do the same all the way down the second rail. If you plate has accurately cut holes, then both rails should be aligned. Also, if those are cheaper Chinese blocks, you may have to completely disassemble them and rinse all bearings and components with ethanol or isopropyl to get all the sticky grease off them. I did that with mine and they slid beautifully after the cleaning. I then used the appropriate grease for their load. There are Youtube videos on how to do it.
Thank you for your response so i snugged up the blocks on the plate i didnt fully tighten them while i was sliding the plate back and fourth i will try it your way and see if that works the plates are from chris (blue ox) i havent heard anything but good things about his work they look good but i havent verified flatness i will try this and get back to you thanks
There is really no need for two rails on each side of the Y axis, and this is one of the reasons. The C-beam faces are not coplaner. Hold a straight edge against the two faces and you will see. I saw a pic recently where someone used a fly cutter to flatten the two faces, but really one rail per side is all you need. Gary
What kind, and how much grease did you use? Here is a guide with lubrication information: https://www.hiwin.com/wp-content/uploads/lubricating_instructions.pdf page 24. Mine made noise as well, but moved well and with grease they quieted down. I think i am using EP1.
Use your indicator to check the running heights of each of your 'cars' - The Chinese MGN12 that I used for the Y axis on my CNC were all different heights. I only got it to run smoothly by swapping the cars around (so that I had the two lowest on one rail, etc.). (Link) If they're all the same height then either your plate is bent or the beam isn't straight - both can be checked with a good straightedge. If you get it running well on one rail, but it binds when you add the second, then the faces of the beam are probably out of plane as @Gary Caruso says above.
