Cutting angles on a CMS

[Mark Kelly]

My CMS will only cut to 45 degrees miter cut. If I wanted to cut, say, a 50 degree angle, could I make a wedge that has a 5 degree angle, place it between my workpiece and the CMS fence? The workpiece then would be at 5 degrees and if I turn the piece to 45 then the effective angle is 50 degrees. Is this plausible?

The only problem I see is inscreaing the angle increases the amount of wood to be cut, which is limited on a CMS.

[Chris Padilla]

Mark,

The one thing to keep in mind when cutting larger/steeper angle on a CMS that stops at 45-degrees is to realise everything is referenced to where the wood meets the saw blade at the fence.

If you make a wedge, its point need to go to the blade just a hair before it gets cut.

If you simply put a piece of scrap at one end of the board so that it sits away from the fence at the necessary angle (use trigonometry), the corner of the board must be right at the fence/blade spot. If the board to be cut extends beynod the saw blade, you'll need to adjust for that extra length.

You could also put the endgrain of the board against the fence (if it is wide enough or use a jig) and cut that way. You then only need move the box 40-degrees since you have a new reference. Think carefully in this case to control the cut to keep it accurate and be safe.

Put a 50-degree angle mark on a piece of scrap and play around...you'll start to see what I am talking about more clearly.

[Mark Rios]

Mark, are these 50° cuts for the roof structure? If so, then use a speed square to mark the line and go ahead and make the cut with a circular saw. The cut will be just fine for your trusses.

[Kurt Aebi]

Radial Arm Saw! Now maybe everyone out there will stop laughing at me for keeping my RAS after getting a Compound Miter Saw!

Actually, you can make a sled-like auxiliary table that is on the correct angle for your needs and use it as your fence. Similar to the auxiliary sled I use for cutting pen blanks safely.