# Cutting Opening in Hollow-Core Doors



## sublime2 (Mar 21, 2012)

How about this to cut the holes?
http://www.diychatroom.com/f29/osciallating-multi-tool-120729/
Many seem to swear by it!


----------



## Daniel Holzman (Mar 10, 2009)

A router with a long, straight carbide bit will work fine. As you noted, the corners will be rounded. Make sure you go the correct direction around the jig, else you will get an inferior cut.


----------



## sublime2 (Mar 21, 2012)

Daniel Holzman said:


> A router with a long, straight carbide bit will work fine. As you noted, the corners will be rounded. Make sure you go the correct direction around the jig, else you will get an inferior cut.


Which is counter clockwise......
Clockwise,it can run away from you.


----------



## 8888 (Feb 4, 2012)

sublime2 said:


> Which is counter clockwise......
> Clockwise,it can run away from you.


Wow, I never thought about the direction! Great heads up to Daniel and sublime2!
So you feel this will give me a nice clean cut edge and not get hung up on the inner material?


----------



## sublime2 (Mar 21, 2012)

Router will run through it like butter with the bit suggested.
Even more reason to hold on to the router firmly and take your time.


----------



## Daniel Holzman (Mar 10, 2009)

Just a word of advice, you will be using a deep bit, so you are best off with a 1/2 inch collet. The cardboard material inside the door will not slow down a decent router, and you can get a great cut. Finishing the corners to get as good a cut is not so easy, I think I would finish the corners with a very sharp chisel.


----------



## woodworkbykirk (Sep 25, 2011)

a router with a proper jig set up will give the best results.. ive done this with a circular saw using a shoot board with no issues. had to do it on 5 doors for a vet clinic we built 2 years ago

an oscilating tool isnt the correct tool for the jobs.. its a specialized tool for specific types of cuts..


----------



## mae-ling (Dec 9, 2011)

Done it once with a circular saw. Knew that the way I was trimming it would hide any small irregularities.


----------



## rjniles (Feb 5, 2007)

If you are not trimming the opening, how will you hide the cardboard filler inside the 2 face panels?


----------



## sublime2 (Mar 21, 2012)

rjniles said:


> If you are not trimming the opening, how will you hide the cardboard filler inside the 2 face panels?


I'd also like to know this for future reference if I should tackle something like this.


----------



## 8888 (Feb 4, 2012)

rjniles said:


> If you are not trimming the opening, how will you hide the cardboard filler inside the 2 face panels?


Not sure you understand the process.
Once the opening is created, there is no longer any support at the opening, so filler lumber must be inserted and glued INSIDE the opening perimeter. This is for support only and does not cover the router cut, as it is inside the door.
The Plexiglas will float centered in the opening, held in place by trim whose ONLY job it is to hold the plexiglas in place. This trim will also not cover the router cut.
So this is why my original question was "how to make an accurate CLEAN cut". Bad cut = lots of post finishing work, Clean cut = very minimal post finishing work. 12+ doors x 2 sides is a lot of unnecessary work!


----------



## ratherbefishing (Jan 13, 2011)

12 doors and a clean cut means router and a jig. I don't think you'll need to, but scoring the veneer will further prevent chipping. Will the plexiglas holding trim cover the end grain? You might be able to find a molding profile that holds the window and trims the opening.
http://www.template-services.com/Profile%20catalog/Moulding%20Types/Corners/Inside%20and%20Outside%20Corners.htm


----------



## mrgins (Jan 19, 2009)

8888 said:


> 1) needs to be a precision cut made through both sides of the door at once.
> 2) trim will NOT be covering the cut, so I need as little damage as possible.
> 3) the material is rather flimsy when unsupported during the cut.
> 4) a jigsaw blade's up/down action would probably make a mess of the underside as it pulls/pushes the flimsy unsupported underside.


1) both sides at once? Transfer your marks with a Tsquare and use a plywood blade
2) Why no trim? A couple of grooves in a piece of 1 3/4" to make a frame that will finish off the cut edge and provide stability and rigidity
3) Shouldn't be a problem with a saw
4) Don't use a jig saw!


----------



## Missouri Bound (Apr 9, 2011)

Most hollow core doors (luan)can be cut with a straight edge and a razor knife.


----------



## Augie Dog (Oct 22, 2009)

Cutting the doors with a router is the way to go for that many doors.

But I still think you should consider a slightly different approach to the trimming of the plexiglass. 

The filler blocks you mentioned are fine. But when it comes to the stops for the glass, you could make up some outside corner molding that creates a stop for the glass and reaches over the skin of the door to cover the cut line through the door and the edge grain of the skin. 

You can play with the proportions of the molding to suit your needs and see what looks best to your eye.


----------



## mae-ling (Dec 9, 2011)

yep^^^^^ or do it in 2 pieces a stop piece then a trim piece


----------



## packer_rich (Jan 16, 2011)

A router sounds fine, but maybe a little bulky. How about a laminate trimmer or roto-zip?


----------



## hammerlane (Oct 6, 2011)

8888 said:


> The opening will replaced with a plexiglass panel.....there are 12+ doors


I can offer not much advice as to how to cut the voids in the doors.

BUT I gots to know. 

Why are you cutting 12 doors and installing plexiglass in the voids??


----------



## user1007 (Sep 23, 2009)

Tape the area to be cut with masking tape to help control any splintering. Not sure I understand how you are going to deal with this looking decent given the cardboard interior of the door either. You might see if you can find a stock marine window with trim or something?


----------

