Understanding Compound Mitre Saws


Compound mitre saws are great for great very precise compound cuts at the end of a piece of wood. You’ll find them mainly used to cut long stock, to carve out picture frame molding as well as crown molding (angled cuts in two planes) and also when cutting out lots of boards of the same length from the piece.

They come with an electric motor that’s mounted on a swing arm – its pivots left and right to create angled cuts, otherwise called mitre cuts. Compound mitre saws are quick and highly accurate – you get the measurements exactly as you had marked them.

If you want to get even more precise and make bevelled mitre cuts, all you need to do is tilt your mitre saw. The motor will pivot left and right but also towards the tilt.

You may worry about their pricing – that they are a bit more expensive than regular mitre saws, but when you consider that they make compound cuts at once, its actually money well spent.

They have only one aspect that may be a bit discouraging though – the motor will not slide and therefore you cannot pull the saw through a wood piece being cut. You have to set the piece on a table and then set the already spinning saw blade down through it.

To overcome this obstacle, you can consider getting a sliding compound mitre saw, which can be viewed as an upgrade of the regular compound miter saw. As the name suggests, once you lower the blade onto the wood on the table, the blade itself can be slid forward. It will allow you to cut much wider pieces. If you combine this with its ability to tilt, it means that you can do very intricate cuts on large pieces of wood.

How do you choose a good compound mitre saw?

  1. The first and most important thing is the blade size, and this of course will be determined by the size of wood pieces you will be working. You can get blades 8, 10 and 12 inches, and the larger the blade diameter, the longer the cuts that you can make. That means, for instance, if think you will be slicing long planks, you should go for the 12 inch.
  2. Also look at the material that the blade is made of because this will tell you what the saw is intended to be used for. Steel blades are cheap and will do for softwood. They dull quickly on hardwood though. There are compound miter saws made of high speed steel blades which is harder and takes a longer time to dull. Carbide tipped blades will stay sharp for a long time, but they are also more expensive. If you are going to be working hardwood, its best to invest in a carbide tipped one – you will save yourself a lot of trouble.
  3. Check to see if it has electric brakes – they will stop the saw blade much faster than if you just put off the power supply. This is a recommended safety feature that you should insist on.
  4. You need to get a compound miter saw blade which has retracting blade covers so that you can guard the blade. They need to be retracting so that they won’t be in your way as you work.
  5. The saw should also come with table extensions that you can install when working larger pieces of wood.
  6. Compound mitre saws will usually have pre-set points for specific angles that are called positive stops. The more, the better for you because the less time you will spend setting up.
  7. Some will come with a dust bag to collect sawdust in.

Compound mitre saws can be pretty heavy, so if you plan to take yours from site to site, that’s another consideration.