Engineers at NSK Corp., Bloomingdale, Ill., have developed a line of linear guides that reduce unwanted noise and vibration, and provide smoother motion.

The new plastic spacers resemble back-to-back Belleville springs, and the slight compression of each spacer between adjacent balls ensures close guidance during recirculation inside the nut.

The Able Spacer (Photo by Photofusion) Universal Images Group via Getty Images. Simple spacers can be made with plastic bottles, Styrofoam cups, plastic baggies, paper, or even toilet paper rolls.

Soft plastic/hard rubber spacers like the urethane Daystar units shown in this article may actually soften harsh hits—at least that's what some owners attest to.