Generally, the block plane is one of the most reached for planes in most shops. Most block planes are small enough to live in an apron pocket, so it is never more than an arm’s length away. Besides the convenient size, they are extremely flexible in their usages.
Specifically, the 9-1/2 block plane is the regular angle (as opposed to the low angle) block plane with the adjustable mouth. The “regular angle” refers to the angle at which the blade iron sits in the plane body, which is 20 degrees. The “low angle” version of this plane is the 60-1/2 block plane, and its blade iron sits at 12 degrees. The primary difference between the two is the low angle’s ability to trim end grain, like when working on a butcher-block top. The only other difference is the feel of these planes in your hand. The 9-1/2, with its slightly higher angle lifting the back of the blade and cap iron, can stretch the smallest of hands a bit more than the 60-1/2.
The adjustable mouth on these planes allows you to easily bring the throat in tight when working to remove extremely thin shavings, supporting the wood to prevent tear out. Just as easily, the mouth can be opened up allowing a thicker, less refined shaving fit through, when working to remove material more quickly. If a thicker shaving was attempted, If the throat set too tight, the shaving would jam and you’d have to stop and clear the shaving, before continuing. This would certainly slow down your work.
As you might have already imagined, these block planes have a wide range of functionality. You can easily use it to put a chamfer on tenons and along the long grain surfaces, breaking the edges of any carcass or box, use it as a smoother on small scale work for face, edge or end grain. The block plane can certainly fill in for a wide range of tasks, even though it may not rise to the level of replacing specific purpose made planes. A pinch hitter can always come in handy.
Since the block plane has its iron in a bevel up configuration, you can also buy a spare blade or two that you can use to hone higher angles. This would allow you to just swap out the irons, if you were working on some really figured wood, as the higher bevel angle on the iron is in essence the same as changing to a higher frog angle in the bench planes (which use the iron in a bevel down orientation). Highly figured woods respond better to a higher angle of attack, which (without getting too deep into the science of it) allows the shaving to release without the normal tear out.
Don’t overlook the 9-1/2 adjustable mouth block plane for your shop. I think you will find it a go-to for a multitude of jobs.
I hope to see some of you at our events across the country. Feel free to come up and say hello.
Lee Laird has enjoyed woodworking for over 20 years. He is retired from the U.S.P.S. and works for Lie-Nielsen Toolworks as a show staff member, demonstrating tools and training customers.