Carpentry and Woodworking - Miter saw - getting the best results?

Hi,

In finishing up a shed I stick built, I spent some time this past week casing a window and some vents. I'm new to miter saws, I have a decent one (Hitachi 10") that cuts well, but I could use some pointers or hints on getting the most of using the saw. Specifically, how do you experts get reliable measurements? Do you measure the overall width of the casing and mark at it's outside width or do inside width?

When mitering, I found I was off in length anywhere from 1/16" to 3/16", not a big problem for the shed but I'd like better results when I re-do my inside windows. My problems most likely were the result of trying to allign the cut with a pencil mark on the casing. If I lay the casing flat on the table (tight up against the fence) and look down, I marked the measurement on the surface facing up. Is the the standard practice? I was thinking that it might be better to mark elsewhere, as the blade cut (at a 45 degree angle) actually doesn't end at the mark.

I'm probably not explaining well and I imagine if I continue to do this I'll get the feel and do better, but any cutting/measuring hints would be appreciated!

Thanks,
Bob

For trim, pitch the pencil. Get a snap off knife for 99 cents and use it to mark the lines. Use the same measure all the time so that all errors in the measure are the same. Always use a square to mark.

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This will eliminate the width of the line as a point of error.

Note on your marks which side of the line is the waste side, the side you will cut off. If you are on the wrong side, your measurements will be off by the width of the blade. Trying to split the marked line will cause errors, too. It is more accurate to set the edge of the blade on the marked line and go from there.

To be accurate on 45 miters, use your try square to carry the mark over the edge so that you can cut exactly on a line rather than guessing or approximating.

Make sure your saw is set square, too.

Hope this helps.

Great ideas! I just picked up a snap off blade set & will give it a try this weekend. Thanks!!

I can never measure something accurately enough to risk cutting to size on the first cut so I cut long, then take off 1/32" at a time by resting the piece against the side of the stopped saw blade and then cutting it (in other words, just cuts off a length equal to the blade kerf).

Wow, Alex, it must take you a REALLY long time to build stuff!

No, I start off about 1/8" over at most. I just ruined too many pieces of stock, especially baseboard. I mean, measuring a 18' baseboard to 1/8" accuracy or better is not something I want to try especially considering that walls are not straight. Besides, I have never found a wall corner that is plumb/square and thus I almost always have to adjust the miter with a block plane. If I had cut it exactly to length, I might not be able to make the adjustment w/o opening the joint and you can only see this by putting the baseboard in place.

Also, if a baseboard is off by more than 1/16" in some cases, it shows and you can't get a clean joint. Using this method + block plane, I can get my baseboard joints to close near perfect w/o using caulk (I still smear a little on for good measure). Of course it helps if the saw is right next to the work place. Also, I'm not a pro so it doesn't really matter how long it takes me but I think my joints are better than most of the high volume pros (they need quantity, not quality).


So summarizing my method -

1. Measure length of wall and add 1/8 to 1/4" depending on how confident you are of the measurement.

2. Cut piece (usually miter).

3. Put piece in place bowing as necessary to get end flush to wall (this assumes previous mitered piece already in place). Note if miter joint is open on top or bottom and by how much.

4. If miter is open, use block plane to adjust miter on top or bottom until it closes.

5. Adjust cut on opposite side until piece fits wall length exactly without bowing (this end will be unadjusted miter).

Not saying my method is the best, it just works for me. I got tired of looking at heavily caulked joints.

Also, I realize the original post was referring to casing which is not as critical in most cases.

Hey sorry Alex, I was just making a joke. It sounds like a great way to get nice, clean joints.

Coping inside corners goes a long way to correcting for slightly off angles, and only one piece needs to be coped instead of two pieces in a conventional miter.