Cutting laminated MDF (or possibly chipboard)

[Bert Coules]

I'm installing a kitchen from a trade supplier: the cabinets were provided ready assembled but the decorative end panels have to be cut to size. I can use two of the existing finished edges for the front and top of the panels but the edges I cut will still be visible even though they'll be at the back and foot, and obviously I'd like to do a good a job as possible.

Any tips for a clean cut? A new fine-tooth blade for the circular saw perhaps? Which cut will be the better, the top face or the underneath?

I have a vague memory of once clamping two sheets together and cutting them as one, which gave a particularly clean chip-free cut on the two inner surfaces. Is that right?

Many thanks.

[Malcolm Race]

Cut with the face side (the one you will see) down. Set the depth of cut to just over the thickness of the panel The blade cuts upwards and so is unlikely to chip.

I have cut worltops this way with no problems

Malcolm

[Bert Coules]

Malcolm, thanks for that. Much appreciated.

[newshound]

Agreed, but the "two sheets" method also works. I think the results depend on how good your blade is. You could do a trial by doing a first cut "oversize".

Enjoying the current "Cadfael" on 4e BTW.

[Bert Coules]

Yes, I planned to do that; thanks.

Kind of you to say so!

[The Natural Philosopher]

cut 4mm oversize and clamp a ruler across as a guide for a router to take the edge down exactly

[Bert Coules]

That's an interesting thought, thanks. I do have a router, bought for a single job some years back and not used since. I'd need to put in some practise.

[John Rumm]

If cut with a circular saw the underside will be clean.

Its only the top surface that chips out, so doing both at once will give three clean sides.

If you need clean cuts on both side of a panel, then either use a sawboard[1] (the board reduces breakout on top of the board, but only on one side (the side protected by the board). So make sure the board is resting on the bit you want to keep!

Or use a shallow scoring cut[2] as a first pass cut before doing the main cut.

[1] [2]

[Bert Coules]

John, thanks for that. I knew about (but have never used) a sawboard but hadn't come across the shallow cut technique before.

[<frde]

You want the blade to pull the surface into the body of what is being cut.

Yes, stops the free side chipping.

[newshound]

(2) is a good tip, I have never tried that. What I used to do, before I discovered sawboards, is to score through the top layer of veneer with a stanley knife along the final dimension line, then cut slightly oversize, and sand or plane down to the final dimension. Especially when cutting across the grain of the top veneer!

[Bert Coules]

I've used the Stanley knife trick but always then sawn along the exact line of the knife cut. The results tended to be a bit variable.

[John Rumm]

Well worth making a set of saw boards IME. They let you get close to table saw accuracy with a hand held circular saw. The nice bit is that the edge of the board defines *exactly* where the cut will be. (use a marking out knife rather than a pencil if you need sub mm accuracy)

If you can spare some sheet goods (9mm MDF or 6mm or 5/8ths ply) cut 4" off the long edge of *both* sides these don't have to be bang on accurate - just straight enough. Flip them over and glue them on top of the new board edges (so the factory straight edge is pointing toward the centre of your board). Once the glue is dry, rip them from the board with your chosen circular saw and blade. Keep one at 8' long, and cut the other into two bits at the 5' mark. You then have a board for full length cuts, one for widths, and smaller one for cross cuts on other stock (sometimes worth gluing and pinning a fence on the bottom of that in the middle for doing easy right angle cuts).

To make the boards work really well I find it good to wax them with a lubricating wax. Do the sole of the saw as well.

[Bert Coules]

John,

Many thanks for those details: it's clearly a worthwhile thing to do.

[Tricky Dicky]

Some of the better table saws come with a small circular scoring blade moun ted in front of the main blade to score the underside which on a table saw is the side which chips. When set up right they do a wonderful job, the one we had at work was a lovely machine, I do miss it!

Richard

[Bert Coules]

Richard,

Yes, a table saw is something I've often wished for. Space and probable usage have always militated against it, unfortunately.

[Bert Coules]

It turns out that the cut for depth - that's to say the cut along the full length of the boards - is just 12mm. And since they're going against a wall that's been clad in plasterboard dot-and-dabbed over brick, I'm tempted to cut two channels in the wall and make good afterwards...

[John Rumm]

Indeed... the scoring cut technique I posted earlier basically aims to do the same thing - just in two passes rather than one.