How do I center cut plywood?

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NCTurner

Gary
Corporate Member
As the title states what is the best way to cut a square hole inside a sheet of plywood? One consideration, I would like to reuse the cutout for a door to the same hole....
 

Joe Scharle

New User
Joe
Gary, I do this sort of cut with my Fein tool. I chop out DT sockets in table legs this way too.
Make a scoring cut all around your outline, then start to work on the thru cuts.

Bring it over, if you like...
 

ehpoole

Administrator
Ethan
You can also make a plunge cut with your circular saw or a suitable jigsaw blade (it is possible to plunge a suitable jigsaw blade without a pilot hole, it just takes more skill).

However, with any sort of cut you will always lose at least the width of the blade's kerf on all 4 sides so it is important that your design can accommodate this loss if you wish to reuse the "waste" piece to fill in that same space afterwards.

Of the choices offered so far, the semi-circular blade on a Fein Multimaster (or equivalent) is probably about as narrow a kerf as you are going to get and it is potentially as good a choice as any.
 

NCTurner

Gary
Corporate Member
Thanks, Fein tool eh, hum.. Joe might take you up on that as a new tool even a knockoff is not in budget ATM. I'll pm you when I get to that point.

I have seen the plunge cut with the circular saw, what is the trick to getting the corners dead on?
 

Skymaster

Jack
Senior User
make a strait edge frame with the offset of your saw, cut to the corner marks with circ and finish to square with jigsaw or handsaw.
 

SubGuy

Administrator
Zach
I don't have experience with the Fein Multi, however, I would tend to think the straightest cuts would be with a circ saw and a plywood blade. +1 on the straight edge. But you don't necessarily need to do a frame if you don't want. I have made these cuts before with no issues. Now for your door. What particular is this projects use? What style door? (i.e. - recessed, flush, face frame) I would think you could add a border or frame to make you door fit properly.
 

NCTurner

Gary
Corporate Member
SubGuy, yes frames are in order, these will be coop windows to house the new younghens...
 

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junquecol

Bruce
User
Why not make a template and use a plunge router? Only make a part way through cut, then finish with a jig saw. Using a pattern trim bit clean up both door and hole. Add stops either to door, or frame and you are done.
 

jerrye

Jerry
Corporate Member
Thinnest kerf: multitool, without a doubt. If kerf thickness doesn't matter, then any of the suggestions will work.
 

Gofor

Mark
Corporate Member
I plunge cut with the circular saw (you can clamp a straight edge to the ply as an edge guide for a really straight cut), and then use a hand saw to finish up the corners, Any difference in kerf/edge on either piece is easily cleaned up with a chisel, plane or rasp. Hardest part is getting into the center of a full sheet. You can lay the ply on the floor supported by 2 x 4s or a sheet of styrofoam insulation so you can kneel on it to get a more comfortable cut.

Go
 

Bas

Recovering tool addict
Bas
Corporate Member
+1 on the multi tool. Another option is to make four cuts (two rip, two crosscut), then glue everything back together (sans center piece) with biscuits or a spline. Not as strong, more work, and in general a hassle, but hey, I'm not a nice person.
 

manfre

New User
Manfre
What size door are you putting in and what type of plywood? Another option might be to cut the door from a piece of scrap. I have some pieces of the textured pre-primed siding left over from my coop build.
 

Jeff

New User
Jeff
It seems that 2 parallel straightedges which guide/sandwich a jigsaw could give a pretty straight cut with minimal tear out if the cut lines are thoroughly scored first.

A couple of DeWalt jigsaw wood blades measured 3/64" t so you'll lose 3/32" total around the entire perimeter of the door. That undersized cut out could be edge banded and trimmed to make up the blade kerf loss. :dontknow:

Are your chicks discerning woodworkers too? :eek:
 

Bob Carreiro

New User
Bob
1) +1 for Bas.
2) If an 1/8" kerf loss is acceptable (1/8" all around your door), use a circular saw and finish the corners by hand.
3) Using a multi-tool (IMO) is too tedious (if the door opening is bigger than a switch plate!), but HF sells one for $20-$25.00. I have two (they're a little heavier than the competition and get warm to the touch, but otherwise, cut quality rests more on blade quality than machine quality). If you go this route, be sure to use a block on top of your work to register the blade against and maintain perpendicular plunges and square & straight edges around the door.

Good Luck!
 

NCTurner

Gary
Corporate Member
What size door are you putting in and what type of plywood? Another option might be to cut the door from a piece of scrap. I have some pieces of the textured pre-primed siding left over from my coop build.

Thats not a coop it's a freaking condo!! Looks great By the way. I think I got this licked, jigsaw or plunge router should get it done. Thanks.
 

SubGuy

Administrator
Zach
Plunge router will have the least amount of tear-out, however with a frame, you can hide all your tear-out, bad edges and tighten up the door a good bit.
 
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