Good Method for Cutting Out a Window

[CyberDruid]

Oh yeah having a big machine would be lots of fun. It's the big bills I would have to shell out for that keep me humble. I've been making hole in all sorts of things for decades using pretty much the same technique as depicted...aluminum, as long as you are only trimming an 1/8" at a time or less is not too bad, but more than that and you need a real machine. The router would be a danger.

Another nice thing about making ac window or vent hole with a template is you could make a trim ring for the interior or exterior out of some other material and it will fit it perfectly.



For instance the second lower opening n this panel will get mesh. Mesh is a pain to keep perfectly in place...hotglue looks nasty..fender washers are hokey...aluminum strips are nice and tap well...but you can also make one out of acrylic in short order if you already have the template.


Here's a piece of UV Reactive Green Acrylic for the trim ring. Use template mounting tape to temporarily but securely attach the piece to your template.


Back your work up with a piece of material (more melamine here) to keep it from shifting or deflecting and to minimize tearout and chipping, and clamp securely.


If you are plunging into the work without cuttnig away the waste area with a jigsaw you may want to follow up the Straight Bit/Pattern-Collar Base routing with a top bearing flush trimming bit to leave a cleaner edge than a 1/2" straight bit would leave intially. You would then be about 1/16" in from the edge which may be a desirable detail...or you could clean up the panel the same way. If the material is thicker than an 1/8" set up the plunge router to take only 1/8" at a time to leave a smooth cut.


You can produce relatively delicate parts this way...


Obviously the part matches the profile of the hole exactly since it came off the same template.


A trim ring like this can be used to sandwich the mesh to the panel with screws. This will keep the mesh flat and allow for it to be removed and replaced if needed.


For this particular vent hole the UV Reactive trim ring is also an aesthetic element...adding a glowing "pin stripe" around the opening when exposed to UV light.

And of course using a second template or just by cutting the outside perimeter of the part carefully you could make an external trim part that follows the profile of the opening.