Kerf cutting mdf....

[Christof Grohs]

I am working on a project which entails kerf mending mdf. My panels are 18" wide x 8' long and are kerfed in 4 different spots. My kerfs are 1/16" wide x 11/16" deep and 18" long. There are about 20 kerfs in each location allowing me to form a 2" radius bend. Aside from using the sliding table on my cabinet saw with 3 thin kerf blades ganged together (to save time) can anyone think of a safer/easier way to perform the kerf cuts? my layout looks like this: __||||___________||||____||||_____________||||__

The whole thing is then bent to form a box. Cutting the kerfs in the middle of the panel gets a little scary.



Thanks
chris

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K.L.S.

[Matt Day]

What's scary about it? Fear of kickback?

(3) 1/16" cuts at 11/16" deep sounds like a lot of work for the saw. Maybe go 3/8" deep on the first pass and then go to 11/16"?

[Brian Gumpper]

When you say ganging the blades together do you mean to make a 3/16" kerf cut (3x1/16") or are there 3 1/16" cuts with a small space between?

[Jamie Buxton]

You could cut the 8' length into two 4' lengths, cut the kerfs, and then stick the 4' sections back together before you bend them into boxes. The 4' lengths would be easier to handle than the 8' length.

[Brad Naylor]

I'd do it on the radial arm saw - I'm assuming you have one with a 24" pull.

[Richard Wolf]

I do kerf cuts all the time when making round steps. You need to clamp a piece of 2x2, or a piece of ply to the back of the mdf to hold it straight or it will be like a wet noodle by the time you are half way done.

Richard

[Christof Grohs]

When you say ganging the blades together do you mean to make a 3/16" kerf cut (3x1/16") or are there 3 1/16" cuts with a small space between?

I'm using 3 thin kerf blades with spacer between them so I get 3 cuts with every pass. The scary part is that even the smallest twist of material causes the kerfs to bind with the 3 blades. If this happens, the kerfs are off than the material breaks when I try to make a 2" radius. I also make a cabinet with 3" radius which is more forgiving. I also get the wet noodle thing....but thats a different topic all together:rolleyes:

[Steve Jenkins]

You can buy radius corners already made that you glue to flat mdf. I don't have the names handy but there are several suppliers of them. try googling curved plywood.

[Jim Thiel]

I would think a sled would work well for this. Two runners, and a bed long enough to support the work while making the cuts closest to the ends without it wanting to flip up, and you could cut all day.

Jim

[Burt Waddell]

Here is a very good, safe and easy way to do this. http://www.youtube.com/watch?v=1qo6My4vTPg

[Ben Grunow]

I met and old portugese guy who made his own CS with a 3 hp motor and wood body/guard and he could run a dado set on it. The best part is that it was set up to run a 16 15/16" blade!

You could make one too?... and run it along a straight edge with your blades and spacers.

I realize this is nuts but I really did see it and I have always wanted a CS with the ability to hold several blades for dado work when framing decks (notching 4x's takes forever). If you have to do this all day long it might make sense.

Ben

[David DeCristoforo]

I would like to suggest an alternate method. I am presuming from your layout sketch that you are making a box with rounded corners. But this method will work with any configuration. You need a large cove bit (or shaper cutter) to form an inside radius in a long block glued up from several layers of material. This block is joined to the straight sections with biscuits, splines, or whatever, glued and clamped. After assembly, a large radius bit (or cutter) is used to form the outside round. I have some shaper cutters for this and also some router bits which are limited somewhat in the radius you can make. The nice thing about this method is that it works equally well for solid wood pieces. If you make a lot of these, having the necessary cutters made up would be a good investment.