Friday, September 2, 2011

Mini-Rhino motor improvement

I know I've written pretty much all I need to about the Otona no Kagaku mini-Rhino kit, but I decided to clean it up a little bit more. The biggest problem with having used the cardboard sheets glued together is that it isn't very solid. The corners tore off when I tried drilling the mounting holes, and the thing sagged under the weight of the battery holder. I was thinking that cutting up a Tupperware container and using a section with a rounded edge would work well enough, and that the edge would add structural stability for the battery mounting. I found the type of plastic container that I wanted at the 100 yen shop and started taking a box cutter to it. The thing was a lot harder to cut than I'd expected. If the blade got in too deep it'd bind up hard. Too shallow and little pieces would go flying. Push too hard and it'd shatter like glass. Fortunately, it was pliant enough to make hand drilling the mounting holes pretty easy. I'd intended to make the plate a little shorter so it wouldn't extend so far to the right of the Rhino, but in the end I kept the extra plastic in case I ever want to add more frills to it later.


(Before)


(After)

The biggest advantage to the plastic plate is that the bolts act like snap-in pins, making it much easier to pull out the motor and replace it with the original squirrel-cage fan if I want to have both styles of motive power (with the cardboard plate, the bolts had to be tightened down with nuts to hold it in place. The plastic plate doesn't require the mounting nuts). The only thing that I'd add if I had the option would be a second small white gear for the motor spindle, instead of having to hand-swap it between the motor and the fan.

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