(Close Window) Topic: Help cutting a 3 sided Crown box
Message: Posted by: twalter (Oct 15, 2005 6:36pm)
I need to make a 3 sided box out of crown molding and I don't know how to figure the angles. The angles are 90, 45 and 45 Degrees. I basicly need to make half a pyramid.

This is for a coffered cieling that I made out of crown modding boxes. This is the last one I need to make and I'm drawing a blank. Thanks.
Message: Posted by: Alter Eagle (Oct 16, 2005 12:58am)
Yes the 45's are acute angle miters. Tough to do... the 90 is easy, it's just a 45 cut in position.
The process is even tougher to explain, since you first have to transfer the real world protractor info onto a miter saw table, then make a jig to get you to the acute angle.

I'll tell you what, I'll go and make a web page tonight and put some rudimentary info on it enough to get you by on this project.
I will be making one for the http://www.installcrown.com web site anyway, eventually.

I'll tell you how first though...

Okay, the 45 degree miter for the crown in position is 67.5 degrees, hard to get so you make a jig that is 45, and then cut at 22.5

I'll explain why that is on the page I'll make, but here is the Miter saw and protractor angles image I've already made.

So to get to that 67.5 you make a jig at 45, then add the 22.5 (45+22.5=67.5).
You have be really careful with an acute angle though as the teeth on the saw are at an angle where they are pulling you into the blade... so it all has to be fastens down the jig & the piece of crown.

If you were cutting on flat using a 52/38 crown (38 spring angle, which is the angle from the ceiling) it'd be a 56.07 miter and a 46.72 bevel. If it's a different spring angle use the generator it will calculate the crown's compound angle cuts for you... but as you can see you need a miter saw that will got to a 56 degrees miter.

Anyway let me got to that page for you... I'm assuming you want this info for Monday.
Message: Posted by: Alter Eagle (Oct 16, 2005 5:02am)
Okay, it's on the internet.. you're the only one to see it so far.
http://www.installcrown.com/Miter_saw_tables_and_acute_angl.html
Does that explain it all well enough with the images?
Message: Posted by: twalter (Oct 16, 2005 12:18pm)
Wow! Thanks so much for the time and detail in explaining how to do this. The site is excellent and I'll start working on it tonight. I buy a lot of stuff from Amazon, so I'll be sure to use your site as jump off to Amazon. I assume that will help you?

Thanks again so much.
Message: Posted by: Alter Eagle (Oct 16, 2005 3:01pm)
That would be great T. every little bit helps. :)
Be sure to get a before and after & post it here so I can get a look.. it'd be great to have your pictures on that page too.
Your jig too..