Most of the cutting problems talked about on the Grumble with chop saws seem to boil down (after operator error is minimized) to either the operation of the saw itself or the quality/type/set of the saw blade.
My personal feeling is that, when you add more joints, knuckles, and pivots to a saw you also add one or two additional points where you can have play in the operation of the saw. What I mean is that a regular miter say is spun laterally to set the angle. Once the angle of exactly 45º is established, the saw should never be moved. Hence the need for 2 miter saws to really minimize the error factor of constantly swinging a single saw back and forth to accommodate both miters. That takes care of the angle set.
Now, the vertical travel of each saw must be carefully checked to ensure that it is a perfect 90º vertical cut. This is done by checking with whatever accurate measuring equipment you can get your hands on. Not all chop saws built for contractor's use are cutting at a dead vertical cut. It isn't that important when cutting a 2X4 to proper length. But, in the framing field, it is very critical. So you may have to tear apart your saw and add shim stock to arrive at a perfect dead vertical cut somewhere in the base of the saw. That should take care of the machine itself doing what you want it to do. the extra joints in a compound miter saw are very seldom if ever needed and simply add to the potential for sloppy movement and play in the operation of the chop saw.
Now, regarding saw blades, you may think that you bought the Cadillac of saw blades but there is a difference of night and day in most of the saw blades on the market today. IMHO, there are about 2 brands of blades that are easily accessible to the framer that are worth the money in terms of a high quality true cutting finish blade. Those would be the Ultramiter blade and the Forrest blade. I have used both and favor the Forrest blade but both are expensive and worth every penny of what you spend for them.
Remember also that the saw blade is as good as the first person to sharpen that blade when it needs sharpening! I always recommend sending these blades back to their respective manufacturers for sharpening, fine tuning, and broken tooth replacement. The carbide teeth are critical to the proper operation of the saw. If you have somebody weld on an inferior tooth or two to one of these blades, they can not only throw off the balance of the blade but can cause run-out, undue vibration, and premature wear on the entire blade's cutting edge.
There are alot of framers who will swear by less expensive blades that are on the market and I agree, they do an acceptable job. But, until you actually cut a piece of oak or ash and feel the glass smooth surface of that miter and the clean slick cut through the moulding, you will not realize the real difference in the quality of these blades.
I will admit that even these blades will have a tendency to cause minor chipping on the back sides of certain gessoed and laquered mouldings, though. Some of these extremely hard/brittle finishes will defy the sharpest most accurate saw or chopper and will give you a ragged edge on the back side (outside edge) of the moulding. That is a built in flaw of the moulding manufacturers in an attempt to get a piece of wood to look like something that it is not. I swear that the finish imparted on some of these mouldings was never meant to be cut!! Period!! They shatter and chip at the slightest contact with a cutting tool.
My last set of Forrest 100 tooth 10" miter blades cost me around $130.00 per blade. I have had them resharpened by Forrest one time and they cut better than when they were bought! There was a chipped tooth on one blade and they replaced the tooth for a nominal charge. When these blades are sharpened, they are ground on ALL faces of each tooth. On an ATB blade that means up to 5 separate grindings on each tooth. That is the proper way to sharpen a fine quality blade! And the amount of carbide removed should be microscopic at most. If you get a blade back from some guy who does saw blade "sharpening" and the teeth are about 2/3 the size that they were when you took the blades in for sharpening, don't go back there. That boy is just destroying the effective life of your blades no matter what you paid for them!
I sure hope that this helps you decide on what you already have and what you may need to get the very best from your miters.
Framerguy
