[Ben Krasnow's] water vortex machine has been an exhibit in the lobby of the San Jose City Hall for quite some time now. Unfortuantely he recently had to perform some repair work on it due to the parts inside the water chamber rusting.

This is the same water vortex that we saw about a year ago. It uses a power drill to drive an impeller at the bottom of a water column to produce the vortex. That impeller was made from painted steel and after being submerged for eight months it began rusting, which discolored the water. [Ben's] repair process, which you can watch after the break, replaces the shaft and the impeller. He reused a plastic PC cooling fan as the new impeller. The replacement shaft is stainless steel, as is all of the mounting hardware that will be in contact with water. But for us, the most interesting part of the repair is his explanation of the shaft gasket and bearings. Two thrust bearings and two radial bearings ensure that the shaft cannot move axially, which would cause a problem with the gasket. He had intended to swap out the oil seal for an all Teflon seal but the machined acrylic wasn’t conducive to the part swap. Instead, he replaced it with the same type of gasket, but bolstered the new one with some silicone to stave off corrosion.

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While we normally don’t make it a habit to feature Kickstarter projects, we couldn’t pass this one up. [Barton Dring] from BuildLog.net is putting together a project called MakerSlide that we’re sure will interest many of you out there.

Through his various CNC builds, he has found that one of the more expensive and frustrating components to obtain is a linear bearing system. He notes that commercial systems are expensive, and while an occasional eBay bargain can be found, it’s not the ideal way of going about things. He also points out that homebrew systems usually work after some tuning and adjustments, but can be time consuming to build.

He is proposing a v-groove bearing system, complete with wheels made from Delrin, as a standardized replacement for all of the aforementioned solutions. He anticipates selling the rails for about 10 cents per centimeter, putting the average cost of a 4 foot system around $20.

As a bonus, he is offering up free MakerSlide materials to anyone that sends him a “new, innovative  or interesting open source design or basic idea that uses the material.” You would only have to pay shipping in order to get your new project off the ground.

Standardization is always good, and seeing this rail system go into production would definitely benefit the hacker community. Take a minute to check it out if you are so inclined.

Taking a cue from the jog wheel we posted last week, [42ndOddity] has built an improved version. The design is based around a solid state rotary encoder instead of an optical encoder. The rotary encoder is far easier to attach and position properly. The knob is milled from scrap aluminum-it was a copier foot. To make the motion smooth, it’s sitting in a bearing from the same copier.