How to Make a Router Slab Flattening Jig

Includes Printable PDF Plans!

This slab flattening sled is a jig that uses your router to flatten slabs on your workbench.  This is especially useful when you don't have a planer wide enough for your piece or a CNC machine.


Gather your Materials

(1) 3’ x 2’ x ¾” plywood (4) 3" bolt (8) washers (4) nuts (4) Low Profile Casters -Fixed Base Router -1.5” bottom cleaning router bit -Drill bit large enough for the bolts to fit through

Download the Free PDF plans found on  Search "Flattening Sled"


Cut Plywood Pieces

Using the provided plans as a guide, cut your plywood pieces to size.


Insert the Router Bit

You will use a bottom cleaning router bit to flatten the slabs using this jig.


Assemble the Pieces

Using the provided plans, assemble the router flattening sled according to the plans and modified to fit your workbench, if needed.


Secure the Slab

Place the slab on the workbench.  Apply shims if necessary to make sure it isn't wobbly.  Put the sled over the slab.


Flatten the Slab

Use all the necessary safety equipment (protect your eyes, ears, and lungs!) and sweep back and forth over the slab.  Make multiple shallow passes until the slab is flat.

For the plans and an in-depth tutorial, visit!