Ringhook

I have a need to cut a 3" deep by 1/4" groove around the entire outside edge of a 3'6" square MDF 3/4" panel. This cut will be required on numerous 3'6" panels (300+) so I will need to make a sturdy jig. I am thinking of using the tablesaw and making some vertical or slight vertical assembly to make sure the 3'6" panels go in straight over dado. This groove will be used to house interlocking tabs (hardboard) to connect all these MDF pieced together making a floor. Any suggestions on best jig\tool setup for this?

johnep

What about using a biscuit cutter?
johnep

Hack

Do they make one that will go 3" deep?

You could probably make an extra tall fence for a TS and dado the edges of the MDF as you said...3'-6" isn't too big a piece to handle.

You could also make a more "portable" version of this using a circular saw. Maybe make a jig that attaches to the saw to keep it perpendicular to the edge. Of course you'd have to run two passes to get the 1/4"...maybe one each direction so you don't have to change the jig???

Let us know how it goes...

Good Luck!

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Hack (a.k.a. Jeff)

dafeesh

I can't really offer any suggestions beyond what has been offered already, but you have me curious. What will you be flooring with 3700 or so sqft of MDF. Just wondering.

Ringhook

The project is a portable sprung floor for dance - yes a very large sprung floor (actually a handful of small floors)... Thank you for the suggestions - I think I will start working on a jig for the TS.

pianoman

There is a saw for flooring contracters called a Jamb Saw...I`m not sure how deep it will cut...you may be able to modify the saw. Have you thought of using a radial arm saw... with an out-board feed table? Rick

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Leo G

3" is a deep cut. I would suggest using a cabinet saw with 2 rip blades side by side with maybe a spacer to get the full 1/4". Use a feather board to hold the MDF tight to the fence.

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Ringhook

Thanks for the suggestions....I dont have a jamb saw or cabinet saw...I have attempted two solutions...one a modified skill saw jig with vertical fences directly attached to skill saw base....a little bulky but seems to be workable. The other solution is to modify a vertical panel saw with a side mounted rail allowing me to run down the panels - rotating the saw 90 degrees. Think this would be better approach for the number of panels i will be cutting.

Graphiti

Just a thought... You could build a 2x4 Sliding saw with a Circular Saw to make the cut. Just based on the number of pieces you have to cut it might be worth it for the added speed and safety.
Randy.

P.S. Make one cut then drop a 1/8" 4x8 panel over the 2x4s and make the second cut and you'll have your 1/4" groove.

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Ringhook

I have modified my panel saw for making this cut.....but for some reason I made this more complex then I should have (after seeing the above diagrams)....i added a vertical run at the end of my panel saw mounted at 90 so I can run the saw up and down to create the groove....much more work then I guess I needed to do....I suk. Thanks for the postings.

edp

that a dado, 3" deep in MDF will probably fail pretty quick. Any flex at the seam with that length of arm/lever will dramatically increase the pressure to seperate the flange from the sheet. By decreasing the depth of the slot, you will actually increase the likelyhood that this joint will survive. In my opinion.

Ed

pianoman

I agree with ED 1.25"s max! And I would a Radial Arm saw with an out feed table. That is ... if it was my job. Rick

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