How To Make A Scrub Plane (template included)


If you ever work with rough-sawn wood, or enjoy trying to make things from firewood, then a scrub plane is really a must-have tool! There is nothing that can help you clean up, join, and flatten a plant more quickly. You can simply clamp your piece in a vise or to a table, and get to work removing thick shavings on the high-spots almost immediately.

Using scrub plane

In this short article I will show you exactly the steps you should take to convert an old smoother or jack plane into a scrub plane. It doesn’t take more than a few hours to do, and it will cover the following:

What planes can be converted to a scrub plane?

Theoretically, any plane can be converted into a scrub plane. However, since we are generally concerned with removing the high spots, or quickly removing material to flatten the board, it is best to use an affordable bench plane that is easy to hold and control. Because of that, smoothers (9″ long) and jack planes (14″ long) are generally the best planes to convert into scrub planes.

Smoothers and Jack planes have two large handles allowing firm control when plowing into rough spots. And they are long enough to maintain some semblance of a flat surface. They are also readily available for low cost.

Where can I find cheap planes to convert into a scrub plane?

When it comes to scrub planes, you aren’t trying to get collector’s items. Any smoother or jack plane will generally do, of almost any brand. And these are very often available on Craigslist, Facebook marketplace, garage sales, estate sales, and even antique or pawn shops. Ebay should be a last resort, as you will inevitably pay shipping, and the online-only aspect makes it difficult or risky to assess if all parts work before buying

But the best models would be a Stanley/Bailey number 4 or 5. For comparison with off-brands, these are 9″ and 14″ long respectively.

And for reference, I’ve never paid more than $15 for an off-brand plane. They just aren’t in as much demand, which means you can generally pick them up relatively cheap.

Checklist for determining if a plane can be used as a scrub plane

These are a few basic questions you should be asking yourself before you purchase a plane to convert into a scrub plane. If the answer to any of these questions is ‘no’, then you should probably look for alternatives.

  • Is the body cracked, or is a cheek missing?
  • Does it have two proper handles (reference a Stanley Number 4 or 5 for what I’m speaking of)
  • Are all parts functional, or can be made functional relatively easy?
    • Does the blade move in or out when the adjustment knob is turned?
    • Does the lateral adjustment blade work?
    • Are the handles robust and not broken? Or if broken are they repaired?

Getting it in good, working order

Before you get started, you should take the presumably used and neglected plane apart and clean/lubricate all necessary parts. If any screws are seized, then either try some penetrate oil or WD-40 to break them loose. You need to make sure the plane parts all function as expected.

scrub parts with wd40
Scrub parts with WD-40, then wipe down to remove grease/oil/grime.

For removing rust, it is somewhat up to you as to how far you go in removing it. If all parts can move, then at a minimum I would try to clean the sole with a razor blade scraper. The iron and chip-breaker should also be somewhat free of rust. You can do a lot of this with scouring pads, razor blades, or if you want to go full blast, citric acid (it works great).

Cambering the iron

The primary job to convert a regular smoother or jack plane into a scrub plane is to camber the iron. You basically will be grinding a curve onto the blade. The image below shows the difference of the final product well.

Scrub Plane blade versus Jack Plane Blade

But in general, you will use a compass to create a desired radius. Most people choose between a two or three in radius (5-7.5 cm). A smaller radius will mean a more aggressive (thicker) shaving. For me, even flattening rough firewood that has been split, I am fine with a 3″ radius.

For your convenience, I made the following template. Click on the image below to open the file, and save/print it scaled for a regular 8-1/2 x 11″ printer sheet. You can print this off and cut out the radius you wish to use. Personally I think a 3″ radius is sufficient, but I provide several options on the template just in case.

Scrub Plane Iron Template

Scrub Plane Iron Template Radius

But in general, what you will do is grind the blade on a coarse stone, rocking your hand to one side for 10-20 strokes, then reversing to the other side so that you can remove the corners and form the curve. Do your best to maintain the ‘flat’ bevel angle, but don’t worry too much. This is a scrub plane. And as such, you are not making a fine finish to the board, but removing large amounts of material to get it relatively flat.

How to sharpen a scrub plane

Sharpening a scrub plane is the same process as when you cambered the iron. You will tilt the blade forward until it ‘clicks’, so the middle portion of the bevel is touching. Then rock it back and forth side to side while sharpening. Now, I don’t mean to do this in one fluid motion. For example, rock the blade to the left, but maintain contact on the bevel so that now the left side is touching. Then, holding the angle constant, move the iron fore and aft for 10-20 strokes. Then, rock to the right, center, and in-between and repeat. Periodically check the bevel to see your progress. Once you can feel a small bur continuously along the backside edge, you can consider the blade sharp. At this point, simply flip it over and give it a few passes upside down, pulling, on a diamond stone.

sharpen scrub plane blade

Since it is a scrub plane, you don’t need to worry about stropping the blade, as you are going to be taking thick, rough shavings. As long as there are no chips or dings in the cutting edge, I will just sharpen to 1000 grit.

Widening the mouth

The next step to converting a plane into a ‘scrubber’ is to widen the mouth. The width of the mouth will determine how thick a shaving you can take. A wide mouth can allow you to take down high-spots really quickly. But know this can also lead to severe tear out if you plane against the grain – so don’t do that unless you are only focusing on high spots!

But to widen the mouth, you will need a thin or small file. Use it to widen the mouth as much as necessary. Also, in case you didn’t realize it yet, you can also move the frog back as far as it will go while still allowing the blade to protrude.

Personally, I find that cheaper off-brand smoothers and jack planes already have very wide mouths. So, you probably won’t need to do much, if any work to open them up. But if you go to use your scrub plane after cambering the iron, but you can’t get a really thick shaving, then the mouth will need to be widened.

Maintenance

There really isn’t any special work to maintain a scrub plane outside of making sure the iron stays cambered. Normal steps like keeping it in a climate controlled environment, or giving it a coat of machine oil to prevent rust still apply.

Read more – benefits of scrub planes

Joe Foster

Hi - I grew up outdoors in nature - hiking, fishing, hunting. In high school I got my first job at a garden center where I learned to garden and landscape. I've been growing plants from seed and designing native plant gardens for over 10 years. I hope to share some of my knowledge with you! You may have seen some of my videos I create on our YouTube channel, GrowitBuildit (more than 10 million views!). You can find my channel here: https://youtube.com/@growitbuildit Additionally I am a wood worker / DIY enthusiast. I enjoy designing/building projects (with hand tools when I can!). I hope to give you some tips and useful information!

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