Saws

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Hole Saws. The team has some light duty hole saws as I recall, but heavy cutting has been done using my set of bi-metal hole saws for the last three years. The bi-metal saws are much harder and stronger, and handle heat a lot better. They are really not that expensive. The most common configuration has a threaded center hole with two or four holes surrounding it. The mandrel screws into the center hole and the side hold carry the torque so you don't get a saw screwed onto the mandrel so hard that you can't get it off. For the smaller saws, there is a smaller mandrel without the torque holes. The slots on the side can be used for removing the plug after the hole is cut. The pilot drill has a flat on it that is held in with a set-screw, so it is pretty easy to make a new one if it breaks. There are hole saws made with different mounting methods, but the method shown here is by far the most common, and lots of companies make saws that work with these mandrels. A less known use for a hole saw is for crosscutting when you can't get a straight saw into position. We have used a 2 to 3 inch hole saw for cutting structural 1x1 or 2x1 off of a robot at a competition to reduce weight. You just cut a hole that is bigger than the piece and file/dremel off the remaining curve.


While we are on the subject of saws, here are a few useful and inexpensive items.

Mini-hacksaw. Just a blade in a handle. Very useful when you need to get into a tight space.

Another one I have is a six inch hacksaw, which uses a shorter and narrower blade. Also useful for cutting small stuff when space is at a premium.

For really fine work, I have a jeweler's saw ($10.) This uses a very fine blade and can be adjusted for different blade lengths and cutting angles. The blades are really easy to break, so you need to keep a bunch around, but they are cheap ($20/gross). These saws are useful for cutting little pieces of metal and plastic in some electronic devices, limit switches, wire terminals, etc. Not normally good for steel, but with a diamond lapidary blade you can cut glass. Normally you install the blade "backwards" so you cut on the draw (when you pull the blade toward you.) This keeps the blade tight during the cut.

For completeness, I will mention coping saws. These were originally designed for scroll work in wood, but with the right blades, they allow detail cutting in metals and plastics. They normally have a deep frame to allow cutting quite a ways into the material. These also cut on the draw, and the blade can be turned to any angle. The school owns coping saws.

Saw blades. For all of these saws, there are a bunch of specialty blades for cutting different materials. Just do google searches. One I keep around is a hacksaw blade for cutting tile and glass. It is just a wire with a very hard abrasive on it. There are also blades that are piano wire coated with diamond dust, etc.