I like the oscillating saw...straighter cut...cleaner...

 

Might use my oscillating saw at the end if needed, but would do and have done it with a trim router, straight and guide.

 

Don't forget to apply painters tape before you make the cut.

Just a FYI. I used a jig saw to enlarge the opening for a built in style oven. It just so happens the wood was hard maple. I burned up three blades making that cut...about 36 inches or thereabouts. I was using a fine tooth metal cutting blade so the cut would be smooth.

 

Remove doors
apply painters tape
use a tri square scribe cut line using pencil first then utility knife cut thru finish of cabinet to prevent chipping
cut line with jig saw use 10 -14 tpi cut shy of line sand to finsih remove tape rehang doors done

 

And use a "reverse-cut" saw blade to minimize splintering on the finished surface,

https://www.boschtools.com/us/en/boschtools-ocs/t-shank-jig-saw-blades-for-wood-t101br-29428-p/

 

And use a "reverse-cut" saw blade to minimize splintering on the finished surface,

https://www.boschtools.com/us/en/boschtools-ocs/t-shank-jig-saw-blades-for-wood-t101br-29428-p/

yep

 

Clay, Brother in law actually suggested the router but I was hesitant. There is such a small area to support the base on I told him I didn't think that was a good idea.

 

That is the reason I said with a guide, the guide supports the router and gives exact cut, like a track saw. But the best thing to use is something you are comfortable using. Many ways to accomplish most tasks.

 

Thanks guys. The painters tape and the reverse cut blade were great ideas.

 

I had to trim about that much from some upper cabinets with a face frame that was too low for our new, slightly taller, refrigerator. I made a wide support with a straight edge that I clamped to the cabinets and then trimmed the face frame with a trim router. The support piece fit inside the cabinet flush with the front of the face frame to support the router and the straight edge was on top of that to serve as an edge guide.

 

Remove the cabinet, run it through the table saw, touch it up, rehang the cabinet.
'Course this works if it's a simple cabinet system sans the crowns, and doodads that seem to be applied now-a-days.

Some time back I changed over all of my drawer slides to bottom mount self closing.
All drawers had face frame rails that needed to be trimmed to accept the new slides, decided to go the scribe, jigsaw, multimaster, bull nose plane, sand, finish technique.

No need for a 'pilot hole' for the blade, just start the jigsaw cut somewhere in the middle, work the cut to the line, cut to one end then cut in the other direction to finish the cut.

Considered jig routing with one of my trimmers but even with reasonable dust control it would have still sprayed too much of it around with all that needed to be done and handling that router/hose in tight quarters would be tough too.

 

Jig saw, but I would clamp in a piece across the cabinet, just above the cut line to run the saw against. Since you're cutting on the push or down stroke, that extra bit of support will help keep your cut straight and help resist any "bucking" induced on the down stroke of the blade. Since the piece you're cutting off will reduce the size of the piece and stability of the saw. To combat that, you could cut a wide piece to fit just above the cut piece and even with its surface. Clamp this to the guide piece and you have extra support whether you use jig saw or router. A little fussy, yet it all but eliminates the risk of having an accidental slip. Sanding and rounding over or breaking the edge will require some refinishing.