miter saw question

[djmst38]

I have a 10" porter cable cms that has been working for me for about 2 years. I upgraded the blade to a 72 tooth Hitachi 10" blade about 5 mos. ago. Just recently I have been cross-cutting some parts for a project that demands accurate cuts. With the saw set at 90 deg I keep getting inconsistent results. Some cuts seem square but some are off by about 1 degree. The fence seems square to the blade because I checked it with 2 different squares and it was right on. I removed the blade and re-installed it and tightened it up very well but the problem persists. It is very frustrating and I am just wondering if it could be the blade? Anyone ever have a similar situation? I would hate to buy another $100 blade just to test that theory. The stock blade is gone.

[cgallery]

Is the workpiece moving during the cut? Can you clamp it somehow? Sometimes adding a little sandpaper (grit-side out :-) to the fence helps, too.

And what plane is the error in? Up-down or left-right?

[Knottscott]

It could be the blade, it could that the blade is over tightened and is distorted a bit out of shape, or it could be the saw itself. Try just snugging the blade up as opposed to white knuckling it.

You could also try a German made Leitz blade from Mike Jackson for abou $22 delivered. Probably a worthwhile upgrade either way IMHO.
10" z60 ATB cutoff neg hook #007 $16
http://www.forums.woodnet.net/ubbthr...v=#Post2572591

[LCHIEN]

It could be the blade, it could that the blade is over tightened and is distorted a bit out of shape, or it could be the saw itself. Try just snugging the blade up as opposed to white knuckling it.

You could also try a German made Leitz blade from Mike Jackson for abou $22 delivered. Probably a worthwhile upgrade either way IMHO.
10" z60 ATB cutoff neg hook #007 $16
http://www.forums.woodnet.net/ubbthr...v=#Post2572591

While a distorted blade can cut a bigger kerf than expected and thus make it hard to hit a line, as long as the arbor is parallel to the piece of wood the face of the cut will be flat and square (picture a wobble dado).

I agree however, that you should not overtighten the blade nut or bolt,
Finger tight and a bit more is all that's necessary, avoid the "death grip".

The only thing that can cause a 1° off square cut is if the wood is 1° off square with the blade/arbor system. Usually this would be repeatable if it was an alignment problem. So therefore it sounds to me like

1) either something is loose or
2) a technique problem.

Check the bevel setting and the fence for problems related to #1,
and make sure that the wood is flat to the fence (and that the wood itself is straight), use an extended fence (if the wood is longer than 12") and definately use a clamp. The sandpaper idea is good, too.

[Hoover]

Is your blade a thin kerf? If it is, be sure not to overtighten the arbor nut.
If it is a thin kerf, then try using a 1/8th inch kerf blade, to see if the problem still exists.

[RayintheUK]

And what plane is the error in? Up-down or left-right?

This is the important question, as it will determine what (if any) adjustments are required.

When cutting square stock, it's possible to misinterpret the results if you're cutting on the face, then checking an edge, so be sure to mark, then check, the same face or edge that is being cut.

If the fence IS square to the blade, then it must be a bevel setting problem. Did you check the blade was square when perpendicular?

Ray.