Mortise Plane Review

V-bracing requires a mortise where the braces cross the reinforcing plate. Cutting this joint by chisel and cabinet makers file is tough work. How about the butt mortise plane? I have acquired two versions of this specialty tool: The T.S. Wheeler and the Veritas Butt Mortise plane. We can use this tool to cut shallow mortises with perfect accuracy and less work. So, which version is best for luthier use?

The T.S. Wheeler Butt mortise plane is very simple, one might say primitive. The blade is hand adjusted for depth of cut using two pieces of finished reinforcing plate material. Set the pieces on a flat surface such as a cast iron table saw top about six inches apart. Put the plane cutting face down on the wood pieces. Loosen the locking knob and push the blade down until it contacts the flat surface. While you are adjusting, press the plane down onto the flat surface so as to eliminate any unwanted height due to slight wood warpage. Make sure the cutting edge is square to the flat surface. Tighten the locking knob. (There are no images showing this blade setting procedure. Hopefully words are enough.)

As always, the devil is in the details.

The T.S. Wheeler Butt Mortise plane is shown below. Braces mounted in my vise have red lines.

Test your blade setting on some scrap wood of the same species as the bracing you are installing. This material should be same width and length as the finished bracing. Depth of cut testing is a validation of tool setting and very important cutting practice. The procedure is cut and fit, cut and fit until a perfect joint is achieved. I find that the initial setting adjustment cuts too deep. The final cut must show that the reinforcing plate sits down in the mortise with no rocking and in perfect alignment with both bracing glue surfaces. Otherwise, this critical glue joint will fail. Hide glue and Titebond must have tight fitting joints. If set correctly and used neatly, the mortise plane is perfect for this procedure.

Before cutting the mortise, double stick tape the two main braces (i.e. the intended “V” braces) together with the glue surfaces aligned. Place in your favorite working vise, glue surface up.

The reinforcing plate should not be less than 1 ¾-inch width by 5 inches and 1/8-inch thickness in a dreadnought sized guitar. Small tops can handle smaller reinforcing plates.

My other plane, the Veritas Hinge Mortise plane, is a beautiful precision instrument. They could use this on the International Space station and on welding robots if any wood were present thereon. (Surely there is some wood somewhere on those new fangled machines.) All Cast iron surfaces are precisely machined. Adjustment is simple, direct, and precise. You don’t even have to touch the blade.

Which butt mortise plane is best for small, shallow mortises required in acoustic guitar V-brace work?

The T.S. Wheeler Butt mortise plane is best by far. The Wheeler can cut a shorter mortise. The Veritas has a mortise length limitation that "cuts" it out of the running. Plus, the Wheeler costs much less.