How to Hand Plane a Board to Final Thickness

I’ve been writing a series of posts about milling lumber by hand. Today, to conclude the series, I’ll cover planing the board to final thickness.

To quickly review what’s been done to this board so far:

1. First, I started by assessing the board and rough cutting the parts oversized.
2. The first face of the board was planed flat with a jack plane and try plane.
3. One edge of the board was planed square.
4. The square edge planed straight, and then the second edge was gauged parallel to the first edge and planed to the line.

So the over sized board is flat on one face and has two edges that are both straight, square to the first face, and parallel to each other. I now have to make a decision about the board’s second face.

The first question I’ll ask is does it need to be planed at all? If, for example, the board is destined to be a table apron for a table that has no drawer, I could leave the inside face in its rough sawn state. No one is ever going to see that face, and if I don’t need to glue anything to that face, then leaving it rough sawn is perfectly fine.

If the second face does need to be planed, then the next question I’ll ask is whether or not it has to be planed to a specific thickness or if it just needs to be cleaned up. Using the table example again, if the board will be a table apron for a table with a drawer, the inside face of the apron might need to have drawer runners, guides and kickers glued to it. The thickness of the apron really doesn’t matter, the second face just needs to be planed smooth and parallel to the first face. In these cases, I will set a marking gauge to the smallest thickness on the board and scribe that dimension on all four edges. I can then use the jack plane and try plane to quickly clean up the face and plane it to the gauge line, removing the smallest amount of material necessary to plane the second face parallel to the first.

But what if the board does need to be planed to a specific thickness, and a significant amount of material needs to be removed to get to that thickness. Using our table example once more, perhaps the board is for a drawer front and the desire is to make it a specific thickness for aesthetic reasons. In these cases, I’ll set a marking gauge to the specific desired thickness and scribe that dimension on all four edges.

After the thickness is marked on the board, it’s a simple matter of planing the second face to the gauge line. However, the plane that I choose to start with will depend upon the amount of material that needs to be removed. If the amount of material on the waste side of the gauge line is minimal, I’ll start with a jack plane. However, if I have to remove a lot of material to get to final thickness – 1/8″ or more – then I’ll start with a scrub plane, which is much more aggressive than even the jack plane.

The typical camber that I put on my jack plane allows me to plane up to about 1/32″ deep, or a hair more, per pass with the plane. If the camber on the jack plane were much more aggressive than that, it could get awfully hard to use in denser woods like cherry, maple and oak, because the blade is 2″ wide. However, the scrub plane only has a blade that is 1 1/4″ wide, so much more thickness can be removed per pass without the plane getting too difficult to use. My scrub planes can hog off 1/8″ or more per pass in the right wood.

However, the scrub plane will leave a much rougher surface than the jack plane will, so if the surface finish is critical and the face needs to be flat, I’ll switch to the jack plane as I start to approach the scribe line. The jack plane can still remove wood pretty fast, but it will make a wider, finer cut than the scrub.

When the board has been planed to within just a few strokes of the gauge line, I will then switch to the try plane. Similar to planing the first face flat, the try plane will further refine the second face and remove much thinner shavings until I reach the gauge line. As the gauge line is reached, thin slivers of wood will be planed off, indicating that the gauge line has been reached and the board has been planed to final thickness.