My Linear Bearing Plan

I have been thinking about this a long time. I don't like a lot of the linear bearing systems that are available. The nicest ones, are too expensive and generally too heavy for what I want for this machine. At the other end of the spectrum, the cheap and simple V-bearings, I really don't think are robust enough for long term use. I think that they make too small of a contact point, and will start eating up the rails with nicks over time. I wanted to design something that you could just go down to your local big box store and without many specialized woodworking or metalworking tools or skills, put together in an afternoon. I also wanted to leave the option for adjustment to keep them aligned and to be able to add bearing surface to make them stronger.   There have been bearings mounted on angle for a long time. It is simple and effective. It is just hard to mount them to anything to make a full bearing because they are odd shaped. My way around this problem is to use a readily available molding profile that they sell at lumber yards. They sell little filler strips that are triangular with 3/4 in sides. This is perfect for filling in the angle and giving a mounting surface.

You might need to knock off the apex of the angle to fit into the angle but this is quick and easy with a plane or sanding block.  This comes out a bit over 1 in wide at the base which can be sanded off, filled in or just ignored, depending on your aesthetics. You can then edge glue this to a rail that can be as wide as you would like to spread the load. If you would like, you can add additional bearings on the moving units to make a stronger support for higher loads. The stationary angle will only a bearing surface. You would not need to get very thick angle. It is being supported by the underlying wood and not structural. It could be glued on or anchored with screws either at the apex of the angle or along the edge. Just somewhere the bearings do not run. If you want a more long lasting surface or something stronger for working with harder materials, go with cold rolled steel.  You get the idea.

The movable bearing sections can be built up into units that you can mount the gantry or the Z axis depending on the location. The example here is a bit thin on the support but that is up to your final design choice. To make longer rails, all you need to do is butt the rail sections together, fill with expoxy (J-B Weld or such) and sand it even.  The rail can be almost fully supported except for the edge to give clearance for the bearings.

The last part would be how to support the overhanging bearing. That can be done with a small gusset that will support the extended arm or you can also make them into bolt on sub-units that can be adjustable for tracking and play. You can have multiple sliding units on each side of the gantry to broaden the stance of the gantry to make it more stable.

This is just a rough idea and the profiles will be developed more to fit in the different locations. Yes, I know there are other ways to make the profile to fit inside the angle. I am going under the assumption that people might not have a tablesaw, router table, shaper, chamfering bit for router, chamfering plane, drawknife,  or any of the other myriad ways that you could reproduce this profile. Again, people who may not have the woodworking skills or tools are the audience for this type of construction.