How do I cut nice mitered corners?

Question

I will be adding moulding and trim to a few rooms after I lay laminate flooring. I have already done this in one room and I was really discouraged with my miter cuts. In most corners, I had a gap of at least 1/4" that I had to fill with caulk even though I set my compound miter saw to 45 degrees.

Does anyone have any advice on cutting better corners?

score 16 · Answer 1 · answered Sep 20 '10 at 18:11

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Keep in mind that for inside corners, you shouldn't be using miter cuts at all -- you should cope them instead. That gives you a joint that appears mitered, but is more forgiving of slight errors and with less tendency to open up over time.

answered Sep 20 '10 at 18:11

Mike Powell

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I had no idea about coping instead of mitering. Thanks for the info – Steve Armstrong Sep 22 '10 at 14:46
No problem! It does take longer but makes a huge difference. – Mike Powell Sep 22 '10 at 15:04

score 10 · Accepted Answer · answered Sep 19 '10 at 18:54

10

There are two possible causes for this:

Your room's corners aren't exactly 90°.
Your mitre saw isn't accurate.

Given you mention you are using a compound mitre saw I'm going to go with the former.

Unfortunately with non-square rooms you're going to have to do this by a little bit of trial and error. Use some offcuts of the moulding or even scrap wood to find the exact angles you need and then transfer those to the actual pieces of wood you are going to use.

answered Sep 19 '10 at 18:54

ChrisF

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So, find the angle of the corner, divide by two, and set my saw to that. I'll give it a try. Thanks :) – michaelkoss Sep 19 '10 at 19:02
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that a pretty good rough cut, but in my experience you still may need to caulk in that joint if you have a house that's far out of square. We have a 100 yr old house, and the geometry of some corners means that using that method means that you'll sometimes have a bit of one of the mitred edge of one of the molding pieces showing. Not necessarily a big deal, but it may not look perfect. ChrisF's suggestion of trial and error on scrap pieces is a good one. – cori Sep 19 '10 at 21:02

score 3 · Answer 3 · answered Sep 19 '10 at 23:35

Are you cutting with the board standing up in the saw like it will be positioned in the room, or with the board laying flat in the saw and using the compound setting to cut it? The reason I mention it is that I once borrowed a saw and it just wasn't as accurate using the compound setting (saw tilted). Swinging the saw left or right, there is usually a detent at 45 degrees and the saw is more accurate.

If you board is too wide, you may have no choice other than lay it flat and use the compound feature.

Brian

How do I cut nice mitered corners?

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