Plinth blocks and those pesky mitered corners

[daninhim]

Hey all you handyfolk out there. I'm looking for some hints, tricks and tools for getting good quality miters on wraparound baseboard plinth blocks.

So here's the deal. My latest project involves redoing the molding in my dining room and office. In the foreground of the attached picture you can see the new molding, which is 1-1/2" thick to cover the gap left by a new Pergo floor. previously it was the standard 80's-era stock molding like what you see in the background (next to Daisy's dog dish) with a piece of 1/4-round to cover the gap, and I thought it looked like crap.

The plinth block that wraps around the door frame took quite a bit of trial and error to complete (not to mention about 60 trips up and down the basement steps) but, in the end I think it came out pretty good.

I've got two questions:

1. what suggestions do you have for handy ways to accurately measure those corner angles?

2. What's the best (not to mention safest) way to accurately cut a miter that is MORE than 45 degrees?

I currently have a Delta 10" tablesaw and a Hitachi compound sliding miter saw in my arsenal. Both saws can be set for a miter of 45 degrees maximum, so I'd need some sort of jig to increase that angle.

[Guest Trace]

I have had the same problem in out home. The 112 year old place hasn't got a square corner in it. When I made the base boards from 10 1/2 inch x 7/8 inch oak there wasn't any room for error. I used a 12" x 18" square, measured the gap, and figured the angle using trig. Then it was a simple matter to make the cuts. I made the pieces mostly on a table saw using a sled. As for the 45 degree max on your saws. Turn the piece over. Subtract the needed angle from 90 and set your saw accordingly.

[PaulMarcel]

Long ago I bought a gauge from Starrett for measuring those angles. It tells you the angle between the arms as well as the halfway (duh, divide the first by 2 ) More important, though, it holds the angle well so I cut the first part according to the "half" angle it shows. I can then cut the second the same and try it in the gauge while I'm in the shop then make tiny adjustments if necessary.

If you don't want to buy such a "bevel" gauge, you can use a regular bevel gauge and a plastic protractor to measure the angle. Leave the gauge locked so you can try the two cuts together.

[iSawitFirst]

I think the first thing I'd do is bring the miter saw upstairs.

When I trimmed out my house I wasn't smart like Paul and didn't use a bevel gauge. I made test cuts, though, using scrap wood and snuck up on the angle. Wrapping two corners with a single board is always tricky.

Another thing you can do is cut all 45' angles and put quarter round on top to cover gaps. It'll also help keep dust from collecting on the top of the base.