Intro: MDF Knob for a Homemade Bandsaw
I am currently building a 14 inch band saw from plans purchased from Matthias Wandel, and they (plans) require lots of little random bits and pieces to be made out of wood. A hand or star knob, though, is actually a fairly common part that many people need in projects, so I decided to document myself while making one.
A knob like this utilizes a simple machine to give the user more force while turning or tightening something. There are many different designs that can be made for optimum ergonomics, but I just whipped up a simple three lobed shape that worked out well. The one in the plans required just a rectangular piece attached to a riser block, with a bolt going through it, and I like to think of my design as a little upgrade.
The total time it took me to make this was only a few hours including the time for the glue to dry. It also is a very simple, easy project and a beginner could easily handle it.
Here is the link if the embedded video does not play: https://www.youtube.com/watch?v=u1lMQ-3vyK0
The materials that you need to make this knob are pretty common. I used 3/4 in. MDF, a large washer, and a 5/16 by 3" long bolt down the middle. You could really use any wood that is available to you. For the tools, I used my little bandsaw, disc sander, router, and drill press. Really you could get away with just a jigsaw and some sandpaper.
Step 2: Transferring Template
A couple days earlier, I played around with some different designs for the handle, and drew the one I liked the most onto a piece of thin plywood. I traced around the template with a pencil, and cut it out roughly at the bandsaw. The riser block was made using a compass and cut out the same way. After that, I used my disk sander to bring the sides up to the line. For the inside curves, I used the little radii on my belt sander.
Step 3: Gluing and Drilling
After the pieces were cut out and refined, I drilled a pilot hole through both of them in the exact middle, and a larger hole through the top piece. After I applied the glue, I used the same drill bit to align them while the glue dried.
Step 4: Bolt and Routing
After the glue was dry, I mixed up some 5-minute epoxy so I could secure the washer and the bolt. I drilled out a larger hole all the way through for the bolt's shaft to fit in. The top of the hole where the bolt's head is pounded in is a little wider, so to prevent splitting.
When the epoxy was dry, I took it over to my homemade router table, and rounded over the edges with a 1/4 inch roundover bit.
Step 5: Finishing
The final step was to paint the wooden surfaces of the knob. I chose to leave the metal bolt and washer to have their surfaces exposed, and just went carefully around them. A trick that I use for letting the pieces dry is to prop them on strips of triangular cut offs, so there isn't much surface area to rub off onto.
I still need to give it a few coats of varnish, which I will do in a few days when the paint fully cures.
Thanks for reading!