I have recently installed a bead-board wainscoting in the stairwell and now I need to figure out how to cap it. My question is how do I figure out the angles to mitre the cap rail? Do I need to use a coping saw or can I just find the correct angles and mitre it?

For the acute angles of a triangle,

included angle = arctan(side opposite / side adjacent)

From there, you should be able to set your miter cut, depending on how your trim pieces lay out.

If you don't have a scientific calculator, use Excel or Windows calculator, or
http://hyperphysics.phy-astr.gsu.edu/hbase/rttri.html#c1

whatever it takes. :-)

your angles for stairs should roughly be 54 deg. on the to and 36 deg on the bottom. Cut those in half and that is what you cut your mitre at. So at the top you will cut each piece at 27 deg. and at the bottom you will cut them at 18 deg. if any questions email me at mccue19er@yahoo.com

This is late.. but if it comes up again, or anything similar for that matter. This is a simple matter of bisecting the angle, but you have to make the real world math match the miter saw table, (I show you that on the crown site too).

There is a tool all of us carpenters should have in their tool box and that is the prosite protractor, you can see it and how I use it on my how to install crown molding site plus I put some stuff up on amazon about it too.

That protractor table matches the miter saw table which is the beauty of it, it was invented by a carpenter just like us too... I put a little article about him on the site.

Hey, use the link from my site though if you pick it up at Amazon, I use the extra pennies to keep that site running. ;)



Alter Eagle Construction & Design

http://www.altereagle.com/ | Construction & Design | http://decks-ca.com/ | Decks, California outdoor living | http://kingofcrown.com/ | Molding and finishing | http://installcrown.com/ | Crown tutorial