Four Row Linear Bearing Rail

This is a 3D printed square rail linear bearing that utilizes four rows of standard .177 cal BB's as bearings. It is similar to the two groove bearing rail I have already published but this rail has four rows of bearings instead of two. This allows for far greater load capabilities and heaver preloads as the balls are easier to recirculate with this design because each row is only making contact with the rail at one point. There is also less slop as the two rows on each side are trapping the rail.

The rail is 220mm long and there are four M4 mounting holes on the rail every 60mm. I also designed some stops that fit into the mounting holes on the rail to retain the bearing on the rail to keep the balls from falling out.

The two row version of this bearing had two screws for adjusting the preload. Since I wanted this version to carry heavier loads I did not include this adjustment so instead I made three different versions of the carriages; light(zero preload), standard.(.002" preload), and heavy (.004" preload).

Capacity

I’ll post a video on my YouTube channel once I test their load capability but it it can handle my 185 lbs and still slide freely no problem. I wouldn’t be surprised if it could handle 500-1000 lbs. I plan on finding out shortly.

Required

• .177 cal BB's
• M3 SHCS x 16mm lg.(4x)
• M3 Nut (4x)

Assembly Video
https://youtu.be/cF8fXATjccQ

I designed a 3D printer that uses these bearing! Take a look!
https://youtu.be/XZXadrjIm_4