Scrub Plane – An Incredible & Versatile Tool

One of the best tools a frugal woodworker can own is a scrub plane. No other tool can do the job of flattening a board for so little up-front cost. And while owning hand planes isn’t that common anymore, largely due to the easy availability of power sanders, power-planers, thickness planers and joiners….a scrub plane is a cheap tool for your toolbox that can do the job of all the aforementioned tools.

When it comes to flattening a rough board quickly, no other tool can match it’s set-up time. You just need to clamp the board down and get to work! And while there are a number of companies that will happily sell you a purpose-built scrub plane, you don’t need to buy one. You just need to find a random hand or bench plane, one with a front or back handle (tote).

I made my first scrub plane out of an old Defiance Jack Plane many years ago, around 2018 I believe. And it is a BEAST. I gave the blade approximately a 3″ radius and now it can hog off up to a 1/64″ (0.4 mm) of material in a single shaving. I have flattened chunks of firewood with it to make stock for Christmas gifts, I have removed saw marks from rough-cut lumber, and I have removed bows, cups, and twists in boards. You know – the cheap boards they sell at big-box stores….RELATED ==> See here for how to buy lumber that won’t warp.

So, in this article I will tell you exactly what a you need to do to go about making your own scrub plane, and show you what you can do with it. And I’m going to be giving you guidelines….not rules! There are an infinite number of possibilities or avenues you could pursue to do this, and all of them will work.

What is a scrub plane?

A scrub plane is a regular bench plane with a cambered, convex iron. When inserted into the plane, it sticks our like a tongue or gouge rather than a straight edge. This allows you to take thick chunks of material off rough cut lumber very quickly. Consequently, in addition to the cambered iron it also will have a wide mouth.

Typically they are 14″ long ( like a Stanely Number 5, or regular ‘jack plane’). You can buy purpose-built scrub planes, and many woodworking books will recommend you do so…but you can modify nearly any bench plane to do the same job by widening the mouth and cambering the iron.

My own personal Scrub Plane is a 14″ Defiant Jack-Plane, which is was made approximately 1930. I paid $10 for it in a rusty disused condition back around 2017/2018. With some elbow grease (and citric acid) I restored it sharpened the iron to have a rounded profile.

What kind of hand plane can be made into a scrub plane?

Just about any two-handled bench or hand plane can be made into a scrub plane. Here are the key features:

• For the single most important factor, you need the scrub plane to have both a front and rear handle (think a Stanley No.4). You will be pushing this plane across rough boards, and it will require some force, so those handles are important.
• The next most important factor is that the mouth of the plane should be wide. A really thin or fine mouth will limit the thickness of shaving you can remove at a single time. So, have it be larger, or at least have the ability to get a file down there to open it if needed. Also, if you move the frog all the way to the rear, you will effectively be widening the mouth.
• The plane should not be valuable. So, if you have a Stanley Bedrock, you shouldn’t modify it! Instead try a $5-$20 plane you find at a garage sale.
• The plane should be at least 9″ long (Stanley No. 3 or 4). “Jack Planes” (14″ long are commonly used). Do not use a block plane, even if it has a front knob. Block planes are mostly intended for one handed use and are not suitable for a Scrub Plane. See this image for a block plane ==>

Primary uses of a scrub plane

The most common use for scrub planes is to remove large amounts of wood from misshapen or warped boards, and for removing sawmill marks from rough-cut lumber. The rounded / convex blade makes it great for taking away really thick shavings quickly. However, it does not make it useful for smoothing or joining a board. For that, use a smoother, jack plane, or jointer plane.

Typical use of a scrub plane

For twisted or out of shape boards, you can carefully examine it using a level to identify places where you need to modify or remove material. Then, mark those areas with a pencil or other marking device. Next, secure the board to a flat surface or workbench and start pushing the plane over the area until the majority of the excess material is removed. Then, follow up with a regular jack or smoother plane to square up/join the board.

How often to sharpen it?

There is no hard rule on sharpening frequency when it comes to any woodworking tool. In general, if it seems like it is taking much more effort to take shavings, then you should sharpen it. That being said, if you are constantly hitting knots in boards or slamming into hard chunks of wood, you should increase the frequency of sharpening, as that kind of duty cycle can lead to chips in the blade.

How sharp to should it be?

Well, a scrub plane isn’t for fancy work. So, you can get by with sharpening to 300-400 grit if you like. If you sharpen to 1000 grit or use a strop, the plane will just dull a bit quicker. Personally, I will sharpen to 1000 grit if there are no dings in the cutting edge.

Scrub plane vs Jack Plane

There are generally two primary physical differences between a Scrub Plane and what is commonly known as a ‘Jack’ Plane (often a Stanley No.5). First, while the jack plane blade will have a square profile, the Scrub Plane will have a convex, or curved profile. The image below shows two blades, one from my scrub plane and the other from a regular jack plane that I have. I placed a straight edge against the cutting surfaces to illustrate the difference.

Summary

A Scrub Plane is an essential tool for those with small shops, or can’t afford a large jointer. Also, if you like to make your own boards from chunks of firewood, or just buy poor quality lumber from big-box stores, a scrub plane can help you flatten a board really quickly.

Since you can buy old off-brand smoothing & jack planes on Ebay, Facebook Marketplace, and Craigslist really cheap, then there is no barrier to entry. Simply purchase one of these and spend an hour or two working it into a scrub plane that will last your whole lifetime!

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