The rise of cost-effective CNC platforms like 3D printers, routers, and laser cutters has gone hand in hand with the availability of affordable and accurate linear rails and extrusions. However, they quickly become expensive when you need something for heavy loads. [Andy Pugh] found himself in need of a large linear slide, so he resorted to making his own with steel square tubing and a bit of PTFE (Teflon).
[Andy] needed a compact motorcycle lift for his small workshop, so he designed one with a single vertical tube that mounts on his floor. The moving part of the lift is a slightly larger tube, onto which the motorcycle mounts. To allow the outer part to slide easily [Andy] machined a set of 16 PTFE spacers to fit between the surfaces of the tubes. The spacers have a small shoulder that lets them mount securely in the outer tube without pushing out. After a bit of fine-tuning with a file, it slides smoothly enough for [Andy]’s purposes. With a large lead screw mounted onto the lift, he can easily lift his 200 kg motorcycle with a cordless drill, without taking up all the floor space required by a traditional motorcycle lift.
Although the Teflon spacers will wear with regular use and, they are more than good enough for the occasional motorcycle service, and are also easy to replace. You may not want to use this on your next CNC machine build, but it is a handy blueprint to keep in your mental toolbox for certain use-cases. These spacers were machined on a lathe, but we found that very similar looking PTFE parts are sold as “wrist pin buttons” for the piston of old air cooled VW engines, and could be modified for the purpose.