How to Flatten a Wood Slab with a Router Sled

Building furniture with with live edge wood slabs can yield truly unique projects that showcase beautiful swirling continuous grain. But conventional planers and jointers simply won't work when it comes to flattening and smoothing a wide slab. That's where a board flattening jig really shines. The router rides on a carriage and trolley on two sets of rails. The bottom of the flattening router bit shears the surface of the slab, so tear-out is almost completely eliminated, leaving a surface that requires much less sanding.

VIDEO: How Does a Router Slab Flattening Jig Work?

NEW! Board and Slab Flattening Router Bits

The innovative cutter design on the Rockler Board Flattening Router Bit (left) and Rockler Slab Flattening Router Bit (right) flattens and smooths roughsawn surfaces quickly and effectively when used in a flattening jig or CNC machine.

The Rockler Board Flattening Router Bit (left) features a 1-1/2" Dia. x 17/32" H x 1/2" Shank. It will help you quickly skim away the roughsawn surfaces of wide boards and slabs when used with either our Benchtop Board Flattening Jig or Full-Size Slab Flattening Jig (#60808 and #59943, sold separately).

The larger Rockler Slab Flattening Router Bit features a 2" Dia. x 11/16" H x 1/2" Shank. It's ready to take on your largest river pour, tabletop or mantel projects, when used with our Full-Size Slab Flattening Jig (#59943, sold separately). Its 2'' cutting diameter will surface large areas in a fraction of the passes required by standard straight bits.

Both bits feature an 1/8" corner radii (right image) to ensure smooth, even overlaps without gouging that can result with other insert-style or sharp-cornered cutter geometries.

Full-Size Slab Flattening Jig

The Rockler Full-Size Slab Flattening Jig is the best choice if you flatten a lot of slabs.

Full-Size Flattening Jig Dimensions

The Full-Size Jig is great for flattening any size slab up to 28-1/2" wide x 78-1/2" long x 2-3/4" thick. Set up the jig on a flat, level base that measures at least 4' x 8'. A flat 3/4"-thick full-sheet of plywood works well.

The Full-Size Slab Flattening Jig features a steel router base and carriage. The precision guide rails and wheeled carriage and trolley let you smoothly guide your router over the entirety of the surface. It also features a brush dust boot and port that connects to a 2-1/2'' dust hose to clear chips.

LEARN MORE: Find all the Features and Specs of the Full-Size Slab Flattening Jig

Benchtop Board Flattening Jig

The Rockler Benchtop Board Flattening Jig is perfectly sized to fit on a workbench or shop stand for routing flat faces on smaller slabs, end-grain cutting boards or resin charcuterie boards — no need for a big drum sander.

VIDEO: Check out the Benchtop Board Flattening Jig

Benchtop Board Flattening Jig Dimensions

The Benchtop Board Flattening Jig has the capacity to handle boards and slabs up to 18" wide x 28" long and up to 1-3/4" thick. Set up the jig on a flat, level base measuring at least 25" x 40".

Benchtop Board Flattening Jig Features

The smaller Benchtop Board Flattening jig features precision guide rails, along with the low-friction carriage and trolley that let you guide your router over the entirety of the surface, machining it flat and smooth.

LEARN MORE: Find all the Features and Specs of the Benchtop Board Flattening Jig