I'm constructing a wood frame. Using 1x4s (although they're really like .5x3.5).
Anyways its going to be 83"x48".
For the ends of the frame, is there any benefit to cutting them at a 45 degree angle (assume visual appeal is a non issue). If I cut them straight, I only have to make one cut per piece of wood since the other end is already straight. If I cut them at 45 degrees that makes 2 cuts per piece of wood.
Will the frame be more structurally sound with 45 degree end over the straight ends?
_______
|\______
| |45 degree ends
| |
| |
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| |______
| |straight ends
| |
| |

 

What is the purpose of the frame?
How are you planning to attach the boards together? Nails, screws?

Personally I would go with straight cuts.
There really isn't enough "meat" to allow you to adaquately screw or nail at a 45 degree angle and it still be structurally solid.

 

I'm building a projections screen. cloth wrapped around the frame. attaching it together by nails with those metal T, L brackets

 

Well then I would absolutely positively go with 90 degree cuts.

I would screw the corners together with coarse thread drywall screws (long black ones) Pre-drill the holes.
Then for extra support, Use the metal L brackets at each corner.

 

thanks for the info

 

One of the main reasons to go with 45 rather than 90 degree cuts is the 45 degree cuts provide more surface area for glue. Any nails are really only there to hold things together until the glue dries.

This might not be much of an issue for you, since you planning on using the brackets. Though, you might consider using some 1/4" plywood and cutting some 8" or 10" triangles to use at the corners. Glue them down and just tack them on to hold them in place while the glue dries. You might also want to put another 1x4 in the middle of the frame to help stablize it/keep it from warping.

A couple other questions:
- any particular reason you are going 83x48? If you are trying for 16:9 aspect ratio, 85x48 would be closer to what you want (still 1/3" off, but close enough).
- are you leaving room along the outside of the cloth for a black border? I should help the appearance of your screen.
- are you actually using a cloth? Not sure that cloth would make for the best screen material.

Not trying to knock what you are doing, just want to make sure you thought things through.