Sunday, August 1, 2010
Eolian has 3 bilge pumps, at different elevations in the bilge. I don't want to get into the philosophy of bilge pump placement and design here - I want to talk about monitoring and control. Two of the bilge pumps were wired direct to the batteries, without switches, lights or controls of any type. Out of sight, out of mind, I guess. One was wired to a decrepit version of the more or less standard bilge pump switch.
I was uncomfortable with this, so I decided to make a bilge pump galactic control center. I wanted to be able to see which pumps were running, I wanted switches to control them, and I wanted easy access to their fuses. Most importantly, I wanted all three controls in the same place, so that there would be one place to look for bilge pump status.
Using a piece of 3/8" teak, I cut out three holes to accommodate three new bilge pump switches, making the subpanel you see above. But, "Wait!" you say, "How did you cut those holes?" (At least I hope you say this.)
The webs between adjacent switches are only about 1/2" wide - any normal cutting method would have broken them out during the cutting process.
Enter the Roto Zip, a tool I was introduced to by Brian on m/v Nawura. This is basically a 1/8" router. The magic is in the bits, which are spiral-fluted like a drill bit. Unlike a drill bit, however, the Roto Zip bits are designed to cut on the flutes. When I got my Roto Zip, it was an exotic tool. Now they are common, and every sheet rock guy has one for cutting out the holes for electrical outlets. Harbor Freight even sells their own version.
Unlike a full-sized router, the small diameter bits are very easy to control - it is not difficult to follow a line with the cut. Unlike a saber saw, the bit puts very little stress on the material during the cut - that's how I was able to leave those 1/2" webs. And unlike a jigsaw, this is a tool that you take to the work instead of vice versa. It fills a niche.
If you get one, also get the circle-cutting attachment. The next time you want to mount an instument and need to make a clean 4" diameter hole, you'll have just the tool for it. (Anticipating your question: yes, carbide bits for cutting fiberglass are available.)