Plywood Square Hole

[unionworkeruk]

I am lining a room with birch ply sheets. The problem is cutting squares for the light and other switches. A jig saw simply shreds the ply and leaves a rough finish.

I would be happier to do it slowly by hand but am not sure what tools to use. Some people say score the square with a blade and then slowly chisel out the area. Others suggest drilling as many holes as possible in the square and then tidying up with a chisel.

I would like some advice on these or any better ways.

Thanks

 

[Deleted member 174758]

Drill the corners out with a brad point twist bit or auger bit. Cut between the holes with your jigsaw, BUT use an appropriate blade, i.e. very fine tooth, brand new (not 6 projects old) and turn the orbit to zero if your jigsaw allows that. Finish into the corners very slowly and carefully and file (wood file) with downward strokes to clean-up if absolutely necessary. Avoid turning the blade in the cut as far as possible as that can twist the blade, meanint tat it willwander off line very easily. Allow the saw to work at it's iwn rate - do not force it

I'd suggest the following blade (for a T-shank jigsaw, U-shanks may be different):

Bosch T101B

Very often jigsaw issues can be cured by using sharp blades - and by selecting the right blade for the job.

 

[Chud]

Of course if you have an oscillating multi-tool that can be used to make neat plunge cuts. You can pick one up for ~25-30 quid if you shop around.

 

[motorbiking]

just get a fine tooth jig blade and make sure you have the outside face down when cutting and the wood fixed so it doesn't bounce. You can also use tape over the cuts to protect the surface.

 

[rsgaz]

if you have an oscillating multi-tool

I used this method at the weekend on a wall that I thought was just plasterboard, but turned out to have ply underneath (I was very surprised it was ply and not OSB). To massively speed up the process, as neatness of a hole that can't be seen wasn't my no1 priority, I went through the plasterboard and ply with a 76mm holesaw, drilled a pilot in each corner and cut up to the pilots with the multitool to square up the corners.

Even though speed was my priority over neatness, it actually ended up looking really neat and I was very pleased with how clean the hole was. This was for a dry-lining box, but no reason you couldn't do this for a galvanised box cutout also.

@unionworkeruk, I am assuming you are making these cutouts before the sheets have been put up though? If so, I'd personally go for a 76mm holesaw, then go into the corners with a fine tooth jigsaw as has been suggested. Don't forget that for double gang, the 76mm circles need to overlap a fair bit and not butt two circles next to each other!!!

Gaz

 

[Chud]

To be honest Gaz you could have just marked out the square hole you wanted and plunge cut it with the multi tool - even drilling the corners I would say is optional. I've got a cheap one from wickes and it gets used mainly for plunge cutting floorboards and cutting out backboxes (old saw blade for plasterboard or TCT grit blade for plaster & brick).

 

[foxhole]

Why are you lining a room with ply?

 

[unionworkeruk]

Because the walls are falling apart and I cannot afford to plaster them. I also like wood

I am also staining the ply mahogany and they look quite good so far. I have one good chimney breast which I have painted a light yellow but the rest will all be wood. It will be lined with book cases of galvinised steel and reclaimed scaffold boards that I am making and another wall with 3 shelves of sliced bark from yew and other wood with great colour and grain.

I have previously lined a small bathroom and lobby with stained wood from old pallets.Takes a lot of time staining the wood etc but I reckon it looks pretty good .

 

[cjard]

Of course if you have an oscillating multi-tool that can be used to make neat plunge cuts. You can pick one up for ~25-30 quid if you shop around.

My local homebase had a load of WORX ones on clearance for £25 each

Additionally you can get round back boxes - if youre gentle with a holesaw you shouldn't ruin your plywood. Use a standard hole saw, not a TCT one
http://www.screwfix.com/p/appleby-circular-dry-liner-box-35mm/90517