[chrisb]

How do most people cut the rough opennings for doors and windows?  I have been using a router table with a flush cut bit that has a bearing and following patterns for the type of openning. The small radius left by the router bit then needs to be trimmed out with a saw or file.  The benefits of this in my opinion are uniform opennings and speed.  Are there other methods that people would like to share? 

 

[bob7094]

For inside cuts I drill a hole in the corner of the opening, and use a scroll saw to cut the opening.

 

[dawgnabbit]

Probably everyone has a different "favorite" method. /DesktopModules/NTForums/themes/mls/emoticons/laugh.gif

For me, a pattern bit in a router certainly is the fastest way (and the neatest, if I make a good pattern) to make many identical openings. If only one or two openings, or many different sized openings, then the old "drill, saw, and file" method works well.

I use a saber saw inverted in a homemade table for the sawing, and I slow the blade speed way down with a router speed control.  I have also tried putting a modified file in this gadget to speed up finishing the openings, but results are mixed.

On plastics, others have reported using the "score and snap" method with success, but it hasn't worked well for me on internal openings.  Some folks have the magic touch, I guess.  I don't.

Dawg

 

[rkapuaala]

I've used all the methods mentioned above depending on the material, plus this additional method on styrene. I have what is called a scribe which I filed a razor sharp edge into. I take the piece that requires the R.O. and move the scribes stop so that it lines up with the top of the opening and score it several times. I do the same for the bottom and sides and then use the back of a razor knife to score it through. It is very slow, but very accurate and clean. I used this on the cab of my engine Lanakila.

 

[Paul Norton]

The cleanest method I found for large internal openings in plastic (windows, etc.) is the following.
 
Lightly score the four sides of the opening with an awl. Lightly score diagonally across the inside of the opening from corner to corner.
 

Drill a very small hole inside each corner. Drill a very large hole in the center where the diagonals intercept. I use a large spade bit or hole saw in my drill press depending on the size of the opening required.
 
Score the four sides of the opening with a box knife or razor knife. Saw the diagonals from the center to the small holes in the corners with a drywall hole saw. If you don’t have that, try a frameless hacksaw or a razor saw. Bend and snap the four pieces out.
 
Square the corners with a square file or sandpaper glued to a square block of wood.

 

[Richard Weatherby]

I have used every method also, but the best method was to hire my son to cut them on his scroll saw. He did a great job!