Replies

1. 
   SteveConroy | Jul 16, 2002 05:08am | #1

   BKWOOD,

   I recently completed a a built in breakfast nook benches for a client. I had to calculate the compound angles for the angled back and the various miters that had to be made as the segments went around.

   I found a web site that lists different woodworking related computer programs available. Some are freeware, some can be run online, some offer trial versions. Among others, I found a program called "PolyCut," which was very helpful. This is the address: http://www.woodbin.com/docs/the_list.htm#Calculators

   Another internet solution is to search under "Compound Miters." I think there are various Excel sheets that detail just about every compund angle combination. Unfortunately, no have I found the mathematical formula to calculate it. I'm sure they could be found in some older carpentry manuals, but I haven't located them yet.

   Happy cutting, Steve

2. 
   uncommontree | Jul 16, 2002 05:46am | #2

   BK.

   I will tell you first off that I am better showing someone than trying to type a description but I will give it a try. First off you are dealing with 2 inside corners so coping will give you the best results,cutting inside miters almost always lead to opening up over time.Run one piece of crown right to the wall.Next place a piece of scrap crown two feet or so(so you can get a good feel while its in the saw and on the wall) in your miter saw upside down and backwards. The flat that go's against the wall is resting on the fence. Next set your miter saw at a 45 deg. Again cutting the side that you want to fit to your already installed piece. Cut your scrap so your long point is towards the back. With a coping saw set so the teeth cut on the up stroke and the blade is tight start cutting along the out line of the face of your crown. A good 30 to 45 deg under cut is necessary to get a good face fit , more will be needed for your 135 deg corner. You can touch up your back with a hand rasp if there are any high spots. Once you have your scrap fit you can move on to your real piece. By placing the crown in the saw upside down  and backwards then setting your saw at a 45 deg. you automatically have the right angle. Hope this helps you out. Rick.......

1. 
   SteveConroy | Jul 16, 2002 06:35am | #3

   BK,

   There is an excellent discussion on compound miter angles in "Finishing. (Message #6932...) Don't ask me why it's in finishing. It's very informative, also has link to site to calculate angles, and printable charts.

   Steve