Overflow Slit Modification
Overflow Slit Modification
For those who have been following closely, I mentioned earlier in this thread that the water level in this tank is just too high. The water level is only about 1/2" from the top of the tank. A surge of current or fish swimming too close to the surface is all it takes to spill over. I have been racking my brains trying to come up with some way to make the slits in the overflow longer. Below is one of my designs for a jig to retrofit the overflow. You may recall seeing this earlier in my build thread.
The only thing I remember from Computer Science 101 was that the simplest coding to achieve the desired result was the most elegant. The above design, while it would probably do the trick, is way too complicated to build and probably too bulky for such tight conditions.
Remembering my CS 101 class, I rethought the whole project. Essentially all I needed to do was keep a cutting tool perfectly straight, aligned with the existing slits, and make sure it cut down to the same depth on all the slits. This is the final result:
How did I do it??
Well the original design was out of acrylic as it is the easiest material for me to work with. The stupid oversight is that the Dremmel spins at thousands of RPM's and ended up melting the jig half way through the first slit. The only other easily workable material was aluminum.
The hardest part of making the jig is making sure all the holes are on the same center line. If they are not then you will end up with angled slits. I mounted a piece of acrylic on my drill press table to unsure all the holes came out in a perfectly straight line. There are four holes to be drilled. One is for the Dremmel bit to fit through (1/8"). Two to accommodate 1/4" dowels which are what slip into the existing overflow slits and act as the guides. The final top hole holds a pin which ensures all the slits are cut to the same depth. My overflow slits are closed at the top. Some peoples are open and you will need to come up with a different design for the stop.
Here are some more photos so you get the idea:
I built 4 because I found that the tough steel shaft of the Dremmel cutting head wares away the aluminum and widens those hole. This creates too much wiggle room for the cutter end will result in messy slits. You can do about 5-7 slits with each jig. If you made it from steel, it would probably last a lot longer. I just don't have the right setup.
And here is what it looks like all assembled and hooked up to the Dremmel:
I am about half way completed on the slit lengthening right now. So far everything looks factory. I will try to post some pics of the result later.
Any questions??? Class dismissed....
Top notch as always though 
