I have this idea for a linear bearing . It would basically be a 20mm x 40mm extrusion with the v rails already formed in place. I was thinking about trying to get it funded via the
Kickstarter program. The extrusion die would then be paid for and the material would be dependent on the production costs only.
The v rail / v wheel bearing is a proven system. Shopbot for example uses this slide system. I have used it on my large wood router for years. It is used on my laser cutter. It holds firmly in all planes except the plane of movement. It even holds strong against rotation.
The current fabrication method is a lot of work. It takes a lot of time to accurately layout the holes, drill and tap them. Any slight misalignment can cause the v track to not be perfectly straight. Also, the thickness of the tapped area is only about 2mm which at best case yields only 3 or 4 threads. Most design standards require 1.5 times the diameter of the fastener.
The goal is to be able to sell the extrusion for less than $3 per foot (I have quotes to support this). The wheels can be expensive, but in qty they are quite cheap. I have quotes in reasonable qty's in the $3-$4 dollar range. That puts a robust 4ft slide in the low $20 range. There are existing designs like this, but they are 5 times the cost and do not work perfectly with the millimeter based extrusions.
I think the open source community could use a cheap high quality standardized linear bearing. I know you can find cheap deals on eBay for some decent linear slides, but it is difficult to base a new open source design on lucky eBay finds. Even those slides require a lot of accurate drilling. A typical maker/hacker could keep 10-20feet of this on hand for quick project
There would be several options
- Anodized alum with Steel wheels
- Anodized aluminum with nylon wheels. Very smooth and quiet, but lighter duty.
- Hard Anodized Aluminum with steel wheels. Hard anodize is extremely hard and would provide years of service in a dirty environment. Rockwell hardness of C60-70.
Here are some ideas that went into the design.
- V-rail does not interfere with standard angle brackets (does now)
- V-Rail center is aligned with the edge for easier designs
- V rail could mount a rail for a rack and pinion drive
- A few extra drill center grooves have been added.
- Fully compatible with Misumi Extrusions and accessories.
I know some of the KickStarter programs have had mixed results, but I think my buildlog.net cred would do a lot to reduce that feeling. My public Internet reputation is worth way more than this little project.
Any thoughts, ideas, suggestions?