Easily handcraft a wooden smoothing plane inspired by those made famous by master furniture maker James Krenov.
A hand plane is an essential tool for any woodworker. In fact, many woodworkers have an arsenal of planes, each for a specific use. Along with the block plane, a smoothing plane is among the most useful to own.
While modern metal planes are certainly well made and highly functional, there’s something wonderful about a finely tuned, wooden bodied hand plane. Take one for a test drive, and you’ll quickly want one for yourself. While they can be bought, wooden hand planes are easy to make, simple to set up and adjust, and a real joy to use. The style of plane we will make is based on a design popularized by James Krenov. While similar in appearance, I’ve simplified the production process for this plane so it will be a little easier to make.
This wooden smoothing plane has only a few basic components: dense hardwood (2" x 31/4" x 14"), a brass rod (3/8" diameter x 31/4" long), and a plane blade (2" wide).
This plane does not need a chip breaker. Because the design calls for a tight mouth (0.003"), a chip breaker would do little to improve the quality of the cut. The mouth restricts the thickness of shavings taken and fully supports the piece being cut to minimize tearout. I’ve built these smoothing planes with and without a chip breaker to prove it to myself.
The blade I am using was custom made for me from 1/4" O1 heat-treated steel by a friend who used a small furnace and some basic milling equipment. However, there are many good options on the market today for obtaining blades. If you don’t know a blacksmith you can always cut down an old plane blade, or better yet, purchase a new one from Hock Tools (hocktools.com).
Find Your Angle
One of the first steps is to decide on the angle of your plane’s blade. Typical bed angles range from 45° to 60°. For smoothing straight-grained woods and moderately figured woods, 45° is perfect — and that’s the angle I’ve chosen for this article. For highly figured woods 50° or 55° will give a better cut, but will require more force to push through the cut. As the bed angle increases, the cutting action goes from a planing action to more of a scraping action. Angles above 60° can be used to make a scraper plane.
With the bed angle chosen and blade in hand, you’re ready to think about the wood. For the plane body, choose a wood species that has good wear resistance so you won’t have to flatten the sole too often. Hard maple is a great choice among domestic species. Most exotics are also good choices. Ipê, a durable Brazilian hardwood, is a great wood to laminate to the sole of the plane to increase its wear resistance. Purpleheart, a relatively cheap and easy-to-work exotic wood, will be used for this example.
Joint and plane your block of wood so that it is 14" long, 2" thick and 31/4" wide (Fig. 1). In order to expose the middle portion of the plane, where you will cut the bed and chip relief, you’ll need to resaw the sides off of the plane. Since your block is 31/4" wide and your blade is 2" wide, you can safely resaw 1/2" off each side. The middle section should be planed down to 1/8" wider than the blade to give some skewing ability for blade adjustment (Fig. 2).
Mind the grain direction
Before cutting the bed angle into the plane, the grain direction should be taken into account. The grain should be oriented downhill as you push the plane forward. Think about grain direction like a broom: as you push the broom forward, the bristles fall back.
Set your bevel gauge to your bed angle, in this case 45°, and mark the bed angle centered on the blank. Mark a second line at 60° in the opposite direction to establish the beginnings of your chip relief cut (Fig. 3).
Cut the bed angle with the base of the plane referenced to the fence of the miter saw. It is a good idea to tune your saw up first for an accurate angle.Remember, if you are cutting an angle greater than 45° you will want to set the saw for the complementary angle. For instance, if you want to cut your bed at 50°, you set the miter saw at 40°, which is your bed angle subtracted from 90°. Once the bed angle is cut, draw a pleasing curve based on your 60° angle and cut it out using the bandsaw. You will want to leave at least 1/8" flat at the bottom of the curve. A good portion of this 1/8" will be removed while flattening the bottom of the plane (Fig. 4).
Assemble the body
With the center section of the plane body cut out (save this piece for later) you are ready to glue the plane back together. At this stage it is critical to establish a proper mouth opening.
Set the halves of the body to where the plane blade almost protrudes. There should only be 1/32" of wood showing below the blade. Having the blade go through at this point will result in a plane with a mouth greater than 0.003" (about the thickness of a sheet of paper).
Mark your plane so you can place the parts back together exactly the same way. Don’t forget to mark the inside edges of the sides, so you don’t apply glue in the blade zone (Fig. 5).
Glue up your plane on a flat surface like a table saw wing or a flat bench (Fig. 6). (Use plastic to protect the cast iron from glue.) Be sure the glueup is flat to the surface and the mouth opening is correct (Fig. 7).
Once the glue has dried, remove the clamps, and pass the plane lightly over the jointer. You want to just flatten the bottom (Fig. 8).
Place the brass dowel
The next step is to locate the hole for the brass dowel that your wedge will contact to hold the blade in place. Transfer your bed angle to the outside face of the plane (Fig. 9). This can be done by using your bevel gauge or by simply transferring the top and bottom edges of your bed to the side and connecting those points. Once you have a line representing your bed angle, place your blade on that line and mark a parallel line. You should now have two parallel lines representing the bed and the blade.
Your wedge will eventually be cut to a thickness of 3/16" where it contacts the brass rod. Since the diameter of the rod is 3/8", by adding half of that (3/16") to the wedge thickness, you can determine that the center hole for the rod should be 3/8" from the blade. Make a final parallel line 3/8" from the blade line. To locate where on that line the hole is drilled, measure up from the bottom 11/4" and mark the final hole location (Fig. 10). This dimension is chosen to leave enough material for support above the hole and give clearance for chips below the rod. The hole is drilled with a letter U bit, slightly undersized for 3/8", and then reamed with an extra piece of brass stock before permanent insertion of the brass rod into the plane. It is important to reinsert the cutoff from the center section to avoid tearout during the drill and reaming process. Insert this block such that the hole is drilled on the short grain side of the wedge scrap. This allows you to cut out your wedge from the remaining material (Fig. 13).
Adjust the mouth opening
The next step in building your plane is adjusting the mouth opening. You want the blade to pass through with an opening just wide enough for a sheet of paper to go between the blade and the body. That will give you a .003" mouth opening. Check your opening with the blade (bevel side down). If you still have 1/16" to go, lightly pass the plane over the jointer another time and recheck. Ideally, you should have between 1/32" and 1/16" between the sole of the plane and where the blade touches the front block. You are now ready to file the mouth opening.
A standard 6" or 8" mill file is perfect for this job. It is important to only use push strokes when filing the mouth to avoid tearing out the grain on the sole of your plane (Fig. 11). Carefully file and check your progress with your blade until you have an opening between the front block and the blade that a piece of paper will just slip through (Fig. 12).
Make the wedge
Now it’s time to make the wedge. The wedge design is critical to the performance of the plane. A wedge made incorrectly will allow the blade to back off during use.
Cut the wedge out of the cutoff from the center section of the plane body, using a long-grain orientation for strength (Fig. 13). The wedge starts at 1/8" and tapers to 1/4" before the going into a curved section. The curve is purely for aesthetics.
The wedge must be adjusted to provide equal pressure on the blade, all the way across the wedge. To check your pressure, press the wedge into the plane with the blade in place. An impression of the rod will appear on the surface. After a few minutes of adjusting with a scraper you can see that I now have an even impression nearly the entire way across the wedge (Fig. 14). Be sure the bottom of the wedge is more than 1/2" up from the blade’s edge to ensure good chip ejection.
Set the blade
It’s now time to try out your new plane! To set the blade, place the plane body on a flat work surface, insert the blade and press the wedge into place with your thumb. With a mallet or small hammer, gently tap on the wedge to set it. To increase the cutting depth, tap on the front of the plane or on top of the plane iron. To decrease the cutting depth, tap on the back of the plane. If you have to decrease the depth for any reason, always reset the wedge. To even out the cutting depth across the entire blade surface, tap on the blade to the right or left to get the blade even with the sole of the plane.
Once you have it set, give it a test drive. You should be able to set the blade to take paper-thin shavings. When well tuned, the chips will be thrown right out of the plane with no signs of jamming.
Once you are happy with the performance, bandsaw the plane to a comfortable shape and enjoy using it. It will quickly become a favorite in your shop.
John Richards began working wood in 2000 with a circular saw, a router and a desire to learn. Today he operates JSR Woodworking, a small, weekend-based woodworking school in Hickory, N.C.