Mastering the Art of Four-Square Lumber Milling

Jan 7


Dave M

Dave M

  • Share this article on Facebook
  • Share this article on Twitter
  • Share this article on Linkedin

Transforming raw lumber into precisely milled, four-square stock is an essential skill for any woodworker. This process involves creating a board that is uniform in thickness, width, and length, with all edges forming perfect right angles. The following guide outlines a seven-step method to achieve this, using common woodworking tools such as a jointer, thickness planer, and table saw. By following these steps, you can ensure your woodworking projects have a strong, stable foundation.


Preparing for the Milling Process

Before you begin,Mastering the Art of Four-Square Lumber Milling Articles it's crucial to have a solid understanding of how to operate your power tools safely. Always consult the manufacturer's instructions if you're uncertain about tool usage. The goal is to take a piece of lumber and mill it to a consistent size, with all edges square to one another. This guide will demonstrate how to mill a board measuring 30" x 4-1/2" x 5/8".

Step 1: Rough Cutting the Stock

Begin by selecting a piece of lumber slightly larger than your desired dimensions. Using a framing square, ensure one end of the board is free from cracks and square it off just beyond any imperfections. With a circular saw, make a square cut, then measure and cut the board to a rough length of 30-3/4" x 4-3/4", keeping the thickness consistent.

Step 2: Ripping to Rough Width

For this step, the table saw is your go-to tool. Adjust the rip fence to 4-3/4" from the blade and set the blade height so the gullet of the teeth matches the stock's thickness. Follow your table saw's instructions, use a push stick for safety, and make the cut.

Step 3: Truing One Face

With the stock at the rough size, it's time to true up one face using a jointer. It's advisable not to remove more than 1/16" per pass to avoid overworking the machine. Determine the grain direction and whether the board is cupped. Place the cupped face down on the jointer table and make several passes until the face is even and free from voids.

Step 4: Truing the Second Face

The thickness planer excels at making the second face parallel to the first. Feed the board through the planer, ensuring the grain direction is correct for a smooth cut. Continue planing until the board reaches the final thickness of 5/8".

Step 5: Squaring One Edge

Return to the jointer, setting the fence at a precise 90-degree angle to the table. With the trued face against the fence, pass the board through the cutter, maintaining steady pressure. Once square, mark this edge for reference.

Step 6: Squaring the Opposite Edge

With one edge squared, use the table saw to rip the board to a width of 4-9/16", slightly wider than the final dimension. Then, make a final pass on the jointer to mill the newly sawn edge to the exact width.

Step 7: Squaring the Ends

A table saw or miter saw can be used to square the ends and cut the board to length. Ensure the saw is cutting at a true 90 degrees, trim one end minimally, then measure and cut the board to the final length of 30", cutting on the waste side of the line.


You should now have a precisely milled board measuring 30" x 4-1/2" x 5/8", with all sides square. While there are various methods for milling lumber, this technique has proven reliable for many woodworkers.

Interesting stats and facts about woodworking and lumber milling are not commonly discussed in mainstream media. For instance, according to a Woodworking Network report, the woodworking industry in the United States has seen a steady increase in the adoption of automated and precision tools, which has led to a significant improvement in the quality and efficiency of milled lumber. Additionally, the Forest Products Laboratory states that precision-milled lumber is crucial for the structural integrity of woodworking projects, as it ensures uniformity and stability in the final construction.