Quick Set-up/Tear-down Slab Flattening Rig

[Tom Hartranft]

I just finished building a quick set-up/take-down slab flattening rig. Individual components are easily carried and set up while also compact for storage when not in use. Will set the rig up on my driveway for ‘good weather’ slab flattening. I used the rails and router rig last summer on the driveway on a crude table setup and decided to do a better job on the table assembly for this summer’s slab flattening. Can flatten up to 28” x 45” with this new rig, variable thicknesses.

Regards,

Tom
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a. Table support. 2x4s friction fit into their mounting attachments for quick set-up/take-down.

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b. ¾” MDF Slab Flattening Table Top with one extra layer of ¾ inch MDF strips under 20mm linear rails to increase flattening height in ¾ inch increments. Have more ¾ inch MDF strips to increase height if/as needed for thicker slabs. Drilled 150 20mm dog holes in the 2’x4’ center MDF top at 96mm staggered spacing along with 150 smaller holes to accommodate threaded inserts if/when needed for slab holding. Bought the rails from Amazon; 2’x4’ MDF from local Big Box store. Mounted router onto phenolic router plate taken from an old router table. Then mounted router plate to 2” aluminum angle that is screwed onto top of linear bearing blocks that came with the linear rails. Weight of the linear rails and router are sufficient to hold the MDF top in place during slab flattening and the Kreg saw tracks are stable under the weight of everything atop them.

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c. Disassembled components now stashed away in my basement workshop and garage.

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[Jim Becker]

That looks good, Tom. While there are a few slight differences in the one I built, "in general", they are very similar. You will enjoy having this capability.

One small tidbit to keep in mind each time you set this up is to not only get the structure as level as you can, but also make sure there is zero twist. I use the method I saw Matt Cremona use for this purpose which basically entails some string and a way to elevate it over the components so you can get the taught string corner to corner on the diagonal, crossing in the middle. When the structure is coplanar, the two diagonals will be touching without deflection where they meet in the middle. For the spot in my shop where I generally keep my table setup (I use it for clamping and track saw work in addition to flattening larger slabs) I had to shim up one foot on the Kreg sawhorse closest to my big door...there's apparently a very slight dip in the concrete there. BTW, I marked the floor at that spot so that if I do break it down, I can put it back in exactly the same spot which will reduce the 'check for level and twist" time in a meaningful way.

[Nick Crivello]

I’ve been meaning to ask and see what solutions people have come up for this; an easily deployable router sled setup for use outside that is also flat.

[Bill Dufour]

Why are these always horizontal? Something like a vertical panel saw with a router would allow then chips to fall away and not be recut.
Bill D

[Jim Becker]

Why are these always horizontal? Something like a vertical panel saw with a router would allow then chips to fall away and not be recut.
Bill D
Well, you could certainly do that if you can find a way to securely hold a heavy slab that might be odd shaped, up and tight to the structure...so the answer is that with a flat flattening table, you have gravity on your side. :) One other potential issue with a vertical or angled setup is that the weight of the router on the gantry could cause it to go out of tram relative to the milling surface, also due to gravity and flex in the gantry structure.

One of the benefits of a knock down system like the OP and I have is that we can "put it away" when it's not in use. I do leave mine up because I also use it as a clamping table and for track saw cutting, but I can disassemble it into three pieces (not including the saw horses and the tracks which are removable) and free up the space...in about 10 minutes.

[Wes Grass]

Vertical needs to be secured? Even tipped back 15 to 30 deg? Gravity is your friend here. Small'ish pieces probably need some kind of restraint even horizontal. Anything substantial you can probably get away with just shimming it 'level'.

A friend does big slabs. 6 x 14 ft, 2-1/2" thick ... forklift required. Tipping them up on edge would be another thing to wrestle with.

[Jim Becker]

Wes, when you are fattening slabs, they do need to be secured so they don't move from the action of the cutting (things move easier than you might think even with something heavy) and for the first side, they are not flat so need to be shimmed and those shims need to be held in place, too. This would be a lot more difficult on a vertical or angled surface than on a flat setup.

[Justin Rapp]

My sled rails, same as yours are just mounted to a melamine sheet. It's a little heavy but I just pull it out out on a folding table that is a good height for me. Takes about 5 minutes to set up or tear down.

BTW - I did find stop collars for the rails that would help prevent the router sled from falling off the rails. I didn't buy them yet since I just have some small clamps I have used on the ends.