From time to time, I need wooden dowels. I use them to plug holes, join pieces of turning together, and sometimes for general woodwork. Dowels aren’t expensive, but if you buy them in, you don’t have much choice of material or size. My homemade dowel plane can make neat, accurately sized dowels of any length, and from any straight-grained timber. Dowels made from suitable hardwood can make decorative contrasting features on a wooden bowl, or fill a defect with wood that blends in with the item.
These planes work like pencil sharpeners and are quite straightforward to make, but limited to one diameter, so you may need more than one. This is how to make them.
Components of a homemade dowel plane:
- a block with a tapered lead-in hole which guides the wooden blank to the cutter. This hole should be about 25 mm deep.
- the cutter, secured by flat head screws to allow a little adjustment
- another block with an exit hole, about 25 mm long and the nominal diameter of the dowel. It steadies and guides the plane along the blank, keeping it aligned with the dowel as it forms.
These dimensions aren’t critical, but seem to work for a 6 mm dowel. If you want to make large dowels, scale everything up. The plane may need a handle to stop it spinning in use.
Making the body
Use a strong, hard-wearing timber such as beech. The plane is in two parts, because this makes it easier to create the seating for the cutter. Take two pieces of beech and turn them to make short cylinders, each about 25 mm long, plus a dovetailed spigot on one end to fit a chuck. The diameter could be about 65 mm. Face off the ends, drill pilot holes, and fit them together with a couple of wood screws. You could insert a couple of dowels too, without glue, to maintain correct alignment. Make sure the screws and dowels will be clear of the tapered hole you will make later. The assembled block can then go back in the chuck while you true up the surface and turn off one of the spigots.
Drill an axial hole right through the two blocks, of the nominal diameter required. Then open up the hole in the outer block to form a taper. This could be done with a small gouge or by scraping with a small skew chisel. Make the sides of the taper straight, and make the taper stop at the junction between the two cylinders. The taper angle is not at all critical, just make the wide end about 10 mm bigger than the small end. You now have a sort of funnel shape within the combined block.
Find a bit of steel for the cutter, about 3 x 25 x 25 mm, though the dimensions are not critical. There are lots of possible sources. I used a short section of an industrial hacksaw blade. A piece of sawblade, hand plane blade, planer blade, knife blade, carpenter’s scraper or chisel will do. You need either high speed steel or carbon steel, (which may need heat treatment before it will keep a sharp cutting edge. If you use steel from a cutting blade and take care not to overheat it while grinding, it should work without heat treatment.)
Into one long edge, cut slots for the screws that will secure the cutter. Make them a loose fit on the shank of the fixing screws. Then you can adjust the cutter position. You can make the slots with a narrow grinding wheel, or if it is soft carbon steel, file them. Alternatively, drill fixing holes in the cutter. Grind a single bevel on the other long side to form the sharp cutting edge. Round off one end of the cutting edge where it will be in contact with the dowel as it cuts. If you leave a sharp corner it will score grooves in the dowel. Take care not to overheat the steel when grinding.
The cutter seat
Now make the seat for the cutter. The seat must be positioned so the blade and its cutting edge will be tangential to the line of the tapered hole, inclined to follow the taper. The cutting edge will be at the side of a slot through which the shavings will exit. Have a good look at an ordinary pencil sharpener to get the idea.
Take the two sections apart. Make a saw cut in the block with the taper, so the cut just grazes the taper. Don’t go past that point. This is the only tricky part of the job, so you could saw clear of the taper and work up to the line with a chisel. Saw another cut that will remove a portion of the block (a bit less than a quarter) and leave a slot in the taper to allow shavings to escape. Make the slot about 4 mm wide at the wide end of the taper, perhaps a bit less at the small end. If it’s too wide, the cut will be too heavy and the plane will be grabby.
Clean up the seat with a chisel so the cutter will lie flat. Drill pilot holes and screw the cutter in place with the bevel side out. Reassemble the parts. Grind off any part of the cutter that protrudes, in case the block spins in your hand when using it.
Using the plane
To use the plane, cut a square section blank, a bit over the required length and a little thicker than the finished dowel, and hold one end in a chuck in the lathe. Run the lathe slowly so the blank doesn’t whip, and catch the free end in the taper hole in the plane. Feed the plane along the blank by hand so the rounded dowel enters the guide hole, and stop the lathe when the plane gets to the chuck.
If the dowel is too tight or too loose, adjust the cutter slightly. It will cut rapidly and cleanly if set up correctly. The dowel will be smooth and almost polished. Remove the blank from the chuck, and tap the dowel out of the plane. Saw off the short bit of waste at the end. If your chuck and lathe make it possible, you might find it easier to hold the plane in the chuck and feed the dowel blank through.