Enlarging hob cutout in situ

[colorado]

Hi, looking for advice here. I’m changing the hob and have discovered the new job needs the cutout to be 5mm wider. Luckily there is about 8mm overhang on the left side of the existing cutout before the end panel of the next unit so I’d like to enlarge the existing hole by 5mm all along the left side.

What is the best way to do this. I have a jigsaw, a circular saw, a basic 1020w router, or a hand saw. Using the router or circular saw I can’t use the edge guide as it’s the “free edge” I’m cutting off, so what’s the best way to get the cut nice and straight. I did wonder about clamping a strip of something on the left as a guide.

Last challenge how do I avoid chipping the top surface. There’s a small overhang with the new hob but I don’t want to spoil the job if a big chunk flakes off.

Any help appreciated.

 

[TicTac]

A jigsaw with a downward cutting blade will do the initial cut, and if you need to clean it up, then getting someone to hold a straight edge (no way of clamping it at the back), will let you use a router, but it won't go right to the back of course. A circular saw needs to be used from underneath, or it'll chip the top.

Just thought, you could use a square piece of wood for the straight guide, and then clamp it at the front with two clamps, and that'd cut down any chance of it moving, or having someone in your way.

 

[foxhole]

Router best for that, if clamping a guide is a problem then a sheet of mdf on top and have someone to sit on it to prevent movement .

 

[colorado]

Thanks both. I used the router to make the first cut but didn't have a bit long enough to go right through 38mm, but anyway it gave me a lovely straight edge with no chipping of the surface.Then I went carefully along with the jigsaw trimming the bottom 10mm or so of the worktop. I used a batten clamped at the front and a helper steadying it at the back.

Now fitting the new oven and have a dilemma. The old one was secured by screws into wooden panels either side of the aperture. I had never noticed but these are extra side panels, screwed to the side panels of the adjacent cabinets. The new oven comes with metal angles to screw on vertically to adjacent cabinets then fix the oven to the metal angle strips. I've done a dry fit and the oven fits fine so I could just screw it to the secondary side panels, or I could remove those panels, fix the metal angles and screw into those. Any ideas why I shouldn't just fix to the existing panels? Probably not a major job either way but interested in any opinions out there.

 

[foxhole]

AS long as the oven is secure when opening the door then either.