Need advice for cutting a very thick slab

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Forum topic by jjagerson posted 08-13-2010 12:00 AM 1047 views 0 times favorited 8 replies Add to Favorites Watch
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42 posts in 2395 days

08-13-2010 12:00 AM

I have a very thick slab of 4 laminated sheets of plywood and MDF (making a benchtop core). The sides are cut pretty square because I cut everything as single sheets before gluing it together but it is still slightly out of square now that it is one piece. HOWEVER, I don’t dare cut it on my table saw because I can’t get either of the two sides flat first to ride against the fence and it is very, very heavy (about 140lbs). I can’t cut it with my circular saw because it is 3” thick and I have only 2.5” of clearance with that tool. I also took a stab at it with my scrub plan but that MDF is a mess. I thought about using a flush trim bit in my hand held router but that is the only idea I have remaining that I havening tried. I even experimented a little with a long jigsaw blade but it gets about .5” into a test piece and just jams up.

Any ideas?

8 replies so far

View DrDirt's profile


4135 posts in 3160 days

#1 posted 08-13-2010 12:07 AM

Assuming you have the space to run the full width and support. You can tack a strip on the ‘Bottom’ sheet edge so that it sticks out say 1/2 inch, like a little outrigger. This piece would run against your fence giving you that first straight cut. Then when you rotated 180 degrees you would have that first flat face.

Good luck

-- 'Political correctness is fascism pretending to be manners' ~George Carlin

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42 posts in 2395 days

#2 posted 08-13-2010 12:09 AM

Dave! That is a great idea!


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560 posts in 2331 days

#3 posted 08-13-2010 12:15 AM

DING, DING, DING!!!! We have a winner!!!haha. Great solution Dave.

-- -Zeke- "I hate to rush off, but I gotta go see a man about a log"

View richgreer's profile


4541 posts in 2492 days

#4 posted 08-13-2010 12:30 AM

Dave got it right and shopguryl added an important refinement.

You should never cut more than about 1.5” in a single pass with a TS.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

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42 posts in 2395 days

#5 posted 08-13-2010 01:23 AM

Ahhhh that does make a lot of sense – thanks! I will do it tonight and let you know how it goes.

Thanks a ton everyone!

View swirt's profile


2106 posts in 2390 days

#6 posted 08-13-2010 04:25 AM

Just in case it is too heavy to wrestle it onto your table saw, clamp a straight edge to it with enough width for the shoe on your circular saw. Make as deep a cut as it will handle, then flip it over and use a bottom bearing flush trim bit, or use a hand saw inside the kerf left by the circular saw.

-- Galootish log blog,

View paratrooper34's profile


865 posts in 2370 days

#7 posted 08-13-2010 05:11 AM

Personally, I would stay away from trying to manuever a 140 lb item through a spinning blade. Seems dangerous to me. I would try to find a way to make the cuts with a circular saw and/or a hand saw. Those two methods reduce risk to you and the piece.

Good Luck!

-- Mike

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42 posts in 2395 days

#8 posted 08-13-2010 06:22 AM

Thanks you all for the great advice. After setting up some supports to attempt the first idea on my table saw (a ridgid contractors saw, not a nice cabinet saw or something) I decided it was going to be too difficult to maneuver the piece and still keep me and the saw safe. – I think you were probably right, paratrooper34. I probably should have mentioned in the first place that I don’t have a big saw.

So I modified the ideas just a bit. I did rip a nice straight piece that I tacked to the surface of the core that my circular saw could ride against. I did that rather than clamping down a saw guide because the core is almost 8’ long and since this is just the core of the top, a couple nail holes won’t really matter in the least. Thanks, Dave & Shopguryl for the idea in the first place.

I did take your advice, Rich and I kept the blade reasonably low. I flipped the top over and did the same thing after measuring very very carefully and wound up with an extremely small bump down the middle of the side that I was able to scrape right off. Everything came out nice and straight. I then squared the two short sides in the same fashion.

This was one of the things i have been sitting on to finish the bench so I will post a picture when I am done. I think it will look very nice.

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