Marking miter cuts

[wreckwriter]

Serious newbie question here. Somehow I'm missing the concept.

Let's say you want to miter the end of a 2x2 45 degrees, using either the SMT or a miter gauge. Setting up the angle is simple but since the short part of the angle is the part that hits the blade first, how do you determine where to cut to end up with the right length on the long side of the board?

I hope this makes sense...

[gimpy]

Not an expert and not real sure if I understand your question. But, I did a 45 miter cut for my router table top trim. I measured from the short side (inside?) of the cut and let the outside take care of itself. I.E., the table was 32 inches long that I was putting the trim around. I made the first 45* cut, then measured 32 inches from the inside part of the cut and then made the 2nd 45* cut (so, the inside cut to inside cut was 32 inches long, exactly corner to corner). The actual length of the trim piece was at least 1 or 2 inches longer that the 32 inch edge of the table. I did it that way all of the way around the table and it matched up perfectly. Make sense? Answer your question?

If not and if a better way to do it, someone will be along shortly, I'm sure.

Frank

[LarryG]

Two answers:

1. What Frank said, also assuming I understand the question. If you're cutting pieces to wrap around something else, measure the "inner" side and the "outer" side will take care of itself.

2. Since you're cutting a 45, the additional length of the "outer" side at each end will be equal to the stock's thickness. IOW, if you're cutting a 24" long piece measured at the inner side, and the stock is 3/4" thick, the outer side will measure 25-1/2" (24" + 3/4" + 3/4").

However you do it, it's best to cut miters slightly long to begin with and make incremental cuts to "sneak up on" the exact length needed to get a perfect fit.

[wreckwriter]

I'm cutting lattice trim for a ceiling, the molding will be flat on the ceiling. The outer side length is the only known length, corner to corner. I guess #2 is the one I need. So if the molding is 2 inches wide the difference between the outside (known) length and the inside length will be 2 inches, right?

Thanks guys.

[jziegler]

Measuring for the molding, measure for the long side of the cut. In my experience, it is always best to measure whicever side you know on the cut. You don't know the exact thickenss of the wood usually, and why take the chance messing up on the math? And Larry is definately right, cut a hair long and trim it down to size. Mark the cut a little long, eyeball it, do a test cut and sneak up on the line. It has worked for me on the miter saw for a good bit of molding. You do lose some length, but you bought some extra, right?

Also, on the molding, the experts will say to cope the inside corners rather than mitering. I've never done it that way, but I understand their point. Seems like a lot of extra work to me.

[wreckwriter]

Most likely I'll cut it on the CMS. It doesn't need to be perfect, its a wooden back porch, but hoping I can get it looking pretty good. I'll be buying the material tonight, will get each board a bit longer than needed.

Thanks again.

[LarryG]

So if the molding is 2 inches wide the difference between the outside (known) length and the inside length will be 2 inches, right?

Two inches at each end. Four inches total.

[wreckwriter]

Two inches at each end. Four inches total.

Right. I meant that if I marked the outside I could measure back 2 inches and that would be the point where blade should meet wood to start my cut. I understood it would be 2 inches on each end. Thanks for making sure though!

I think it will be easier on the CMS but I just got my Shark guard so I'm kinda looking for things to cut on the BT.... After I finish the world's longest back porch rebuild project I'll have time to do some fun projects.

[agent511]

I would think that with the CMS, you could mark and cut either the long or the short side accurately. Especially if you use a sacrificial fence underneath.

[newbie2wood]

I don't really understand what you are trying to do. You know exactly the length of the outside dimension. Measure out your molding at that length and set your CMS at 45 degree. The short side will take care of itself.

Are you attempting to measure the inner and outer side, scribing a line, and holding the molding at an angle to the blade? The proper way on a miter saw is to swing the blade left or right.
________
LovelyPeppy live

[wreckwriter]

I knew how to do it with a CMS, was just trying to figure out how it might be done on the table saw.

I ended up using the CMS, much simpler. Got it done yesterday, came out nicely.

[WEG]

Hi Wreckwriter;
I know what you are looking for... You are looking for a set up using the SMT as I understand it. I just did some trim for my fireplace (and made a little kindling at the same time ) What I did is first cut a 45 degree piece with the SMT to check the angle of the SMT. If that's OK then take the piece you just cut and place it against the blade (saw off of course) and then slide it to the table in front of the blade and mark a line on the saw table at the cut. Sort of like a "skinny Red Line". This is the place you will line up with the outside dimension of your 2x2 mitre, or inside dimention, it doesn't make any difference. Put your marked trim on the SMT, line up the marks, and VIOLA, you got it..
Hope this helps out in the future.
WEG

[newbie2wood]

The concept is similar on the SMT or miter gauge. Assuming the Gauge is accurate, set the blade to 90 degree and the gauge to 45 degree.

On my miter gauge, there are two 45 degree settings. One is on the right and one to the left of the center line. The setting determines whether the long side or the short side of the molding contacts the blade first.

Personally, I prefer to cut my moldings on the SCMS. This reduce switching the table saw on and off a zillion times. It cheaper to replace my SCMS than the table saw.
________
Liane live