Simple Slabbing Jig for Bosch Colt Palm Router

I had a couple small wooden parts that needed to be a custom thickness. I don't own a thickness planer. This jig allowed me to get the job done.

Operationally this works as follows:

• tape down the part in question to a flat work surface. I happened to have a half-sheet of Melamine
• choose and attach appropriate height spacer blocks ("shoe")
• set the bit height in the router
• run the entire jig across the flat work surface to do the planing operation.
• adjust the bit height and repeat

To get a proper fit of the EMT into the printed parts, some sanding may be needed. See part "Sanding-Arbor" for that; cut a small piece of sandpaper, insert an edge into the slot in the arbor, curl it around the arbor. Then using a drill, sand the cylindrical inside surfaces of parts "Foot" and "GuideCollar" to fit as desired.

Note: the router isn't meant to slide along the EMT rails; the entire assembly there is moved across the work surface

Three heights of the riser blocks ("Shoe") are included: 18mm, 30mm, 40mm.

If you want to adapt this to a different router, see drawing "BasePlate" for dimensions for mounting.

If you need different riser heights, see drawing "Show" for the as-designed top surface dimensions. Extrude a part to whatever height you need.

Other parts used

• double-sided tape to hold down the wood in question (or hot glue gun glue applied at board edges)
• 1/4" shank spoil board bit for the router
• 3/4" (18mm) EMT conduit for the rails.
• No. 8 machine screws and nuts to attach router Base to the GuideCollars
• No. 6 screws to attach Shoe pieces to the Foot pieces.
• flat surface to work on

My workflow

• I used a machinist surface gauge [1] to probe the high spot of the board to be planed
• I chose a stack of gauge blocks [2] matching the probed height
• I dropped the router bit down on that gauge block stack, locked the height, then did a routing pass.
• I then dropped the gauge blocks stack height by 0.5 mm (or 1.0 mm), reset the router bit height, and made another pass
• repeat that until the full surface has been planed.

[1] https://littlemachineshop.com/products/surface-gage

[2] https://www.thingiverse.com/thing:5437757