Making a Wooden Smoothing Plane

Making your own plane is a great shop project that results in a fine tool that you will use on a regular basis. 

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A good metal smoothing plane costs around $350 these days, while the cost of a wooden smoother is essentially the price of a stout blade at $50, plus about $20 for a piece of dense exotic wood. There are several key features that come together to make a smoothing plane work well. Vibration is something to be avoided. We do this by selecting a dense hardwood such as Jatoba, maple, or, if you want to make the plane more interesting, try cocobolo or bocote. All of these dense woods do a good job of reducing vibration. My favourites are cocobolo for its density and beauty, followed closely by bocote for its density and feel.

Things to Consider

Any smoother must have a sole that is dead flat – within 0.001″ across the sole. It is especially important on a smooth­ing plane to have the sole touching immediately ahead of the mouth. This ensures that the wood ahead of the mouth is held down, which prevents splitting ahead of the cut dur­ing planing. It is true that wooden planes move very slightly with moisture changes, but unless you have a very wet period, the effect on the plane’s performance is negligible. The plane is rather small, so wood movement is not a significant issue. Orientate the grain direction on the plane sole so that it points toward the rear of the tool. This will mean that you are not pushing a tool with the sole fibres pointing forward.

To reduce vibration during cutting, a typical iron will be 3/16″ thick or more, with a stout cap iron to further support the blade. For a smoothing plane, we use a 1 ½” wide blade because the cheeks of the tool add about another ⅝” and we need to be able to comfortably hold the tool. These thick blades are much easier to hone. With wooden planes, we grind the primary bevel at 25 to 30°, and then hone at the same angle. Hone these blades with the heel and toe of the hollow ground primary bevel touching the stone simultaneously – this makes honing simple to do by hand and very repeatable. Make the mouth opening small to reduce tear-out ahead of the cut.

The nice thing about making your own plane is that you can select the plane body material, the bed angle, the mouth opening and the shape of the tool. I have made many wooden planes: smoothing planes, jointers, coopering planes, hollow­ing planes, scraper planes and tiny one-handed smoothers.

Core and Cheeks

• Start with a square dry blank of dense wood: 14″ x 2 ½” x 2 ½”.
• Set your band saw fence to rip the plane cheeks at ⅜” thick.
• Rip the left cheek off and set it aside; it will run through the planer later to clean up the ripped face.
• Run the remainder of the blank through the planer, to clean up the ripped surface.
• Set your band saw to cut the core of the plane at 1 ⅝” wide. This width takes into account that you need the core 1 9/16″ wide, finished, allowing 1/16″ of space for blade tilt adjustments.
• Plane the core to 1 9/16″ wide using your surface planer.
• Using the planer, reduce the thickness of both cheeks to 5/16″ finished.

Bed Angle and Front Ramp

• Establish the mouth position 1″ forward of center on the core block.
• Draw the bed on the core side at 45° extending up from the mouth.
• Using the table saw, cut the bed angle – ensuring that the cut is 45° to the sole and 90° to the core sides.
• Check with a square to see if the bed is 90° to the core sides; if not, use your block plane to correct this angle.
• Draw a front ramp angle of 60°. Cut the front ramp using the band saw. Keep the triangle cut off from the mouth area, you will need it later. Cut an arc in the ramp starting at a point ½” above the sole – this makes it easier to get your fingers in to clear the throat.
• Cut a slot down the center of your 45-degree bed using your router table. Use a ¾ inch straight router bit, and cut the 5/32″ deep slot from the top of the ramp stopping ¾” from the sole.

Layout Front and Rear Ramp Positions

• On the bench top, clamp the rear core section to the right cheek with the back of the core aligned to the rear end of the cheek. Trace the bed location onto the inside of the right cheek.
• Place the front ramp close enough to the rear ramp so that the blade contacts the lower edge of the front ramp 1/16″ up from the sole when you slide the blade down the bed.
• Clamp the front ramp in place, and trace the 60¼ front ramp on the inside of the right cheek.
• Remove the front ramp, and then trace the profile of the iron onto the right cheek.
• Draw a line on the cheek, parallel to the sole, 1 ¼” up from the plane bottom.
• Draw a line parallel to and ½” above the cap iron.
• The intersection of the two lines locates the center of the cross pin.
• Using a square, transfer the cross pin center location to the outside of the cheek for drilling.

Dowelling the Ramps into Place

• Assemble the plane parts and use F-clamps to hold the core sections secure in place.
• Drill holes through the top and bot­tom of the cheeks on both sides at the extreme ends of the plane to accept ¼” registration dowels. The dowels extend ⅜” into the core.
• Place the triangle cut-off into the mouth area for support and then drill the 5/16″ cross pin hole.

Making the Cross Pin

• Mill a piece of sturdy hardwood: 14″ x ½” x ½”.
• Set the blade height on your table saw to make a tenon on either end of the cross pin that is a ‘fat’ 5/16″ (about 1/32″ thicker). This allows room to hand shape the tenon into a cylinder.

• Make a tenon on the end of the cross pin stock that is longer than the cheek is thick – about ⅜” is fine. the table saw to ‘nibble’ the tenon into shape by making successive cuts.
• With the plane clamped together, place the cross pin shoulder against the right cheek of the plane, and mark the opposite shoulder location at a point even to the inside of the left cheek.
• Nibble the second tenon using the table saw.
• Using a shop knife/chisels/files, shape the tenons into a cylindrical shape – test both in the cross pin holes until you have a snug fit.
• Ensure that the bottom edge of the cross pin is parallel to the bed – this is critical.
• Round the top of the cross pin into a ‘bread loaf’ profile.
• Erase all layout lines now, before you glue up the plane.

Note: It is preferable to have 1/32″ of lateral movement in the cross pin, rather than having the shoulders tight between the plane cheeks causing binding.

Glue Up

• Place the cross pin into the right cheek so you don’t forget to install it.
• Place the eight dowels into the cheeks and apply glue to the core.
• Assemble the plane, and clamp the assembly using several F-clamps and clamping cauls on either side of the plane. Remove squeeze-out and allow plane to dry overnight.

The Wedge

• Make the wedge from the triangular cut out according to the diagram below.
• Saw off the plane ends to remove the dowels.
• Trim the cross pin ends flush to cheeks.
• Run the plane bottom once over the jointer machine to true the sole (without blade!).
• Insert blade, tap in the wedge to stress the plane body.
• Hand flatten the sole on a true sur­face, using sandpaper (retract iron ⅛”).
• Using a file, slowly open the mouth so that the plane iron just passes through.

Shaping

• Use the band saw to create a shape similar to that in the photos. Keep the leading edge of the tool high, to improve your grip. Round the rear of the tool and thin the cheeks at the rear for a comfort­able grip.

Using the Plane

Use a plane hammer to tap the blade to increase the cut. Tap the rear of the plane body to reduce the cut depth. Tap the wedge into place using the same hammer. Make sure the wedge touches the cross pin all the way across – if not, file the wedge to get a good fit, which is critical to your depth of cut adjustments.

Your new smoother will give you a lifetime of service. It takes a day or so to get used to mak­ing adjustments with a plane hammer, but the results are well worth the effort.