What is a Router Sled?

For decades, people have been building router sleds out of plywood, MDF, or solid wood. Essentially, they are used to flatten pieces of wood. Small sleds are often used to flatten cutting boards - end grain cutting boards specifically. Although many woodworkers have planers to send long grain cutting boards through, end grain cutting boards cannot be sent through planers, as there is a massive risk of the cutting board “exploding” due to the angle of the planer’s blades. This is often solved by having a large drum sander, a specialized tool that can be used to surface and smooth end grain boards.

Larger sleds are generally used to surface tables and slabs, simply because they cannot fit in most planers or drum sanders, and most woodworkers do not own large CNC routers. Standard router sleds work by having a set of wooden rails on either side of the piece that needs to be surfaced, and then a gantry that slides up and down those rails. A router with a large surfacing bit is then placed on top of that gantry and slid side to side with the bit spinning, to flatten the workpiece. One of the main issues with the standard homemade sled lies in the materials that they are made of - wood. Wood moves as temperate and humidity fluctuate, and therefore is never completely flat. Any issues with the accuracy and flatness of the router sled multiply and result in issues with the workpiece.

The second issue with homemade sleds is the possibility of error with the router skipping or flying up. In most sleds, the router is not attached to the sled, it only slides on top of it. Because of this, the router can skip or raise up at certain times due to any figuring or knots in the wood, causing the workpiece to have marks and not be smooth.

In general, homemade router sleds can be used to get a rough surfacing of a piece, but cannot be expected to produce a perfectly smooth and accurate result product.