For the final project I decided to make a roller that can burn a QR code on wood. It would be made out of 1″ aluminium stock with a heating rod inside. I would primarily use the 4axis mill.
First I had to generate the QR code, and because it had to be milled, I needed something with rounded corners. Thankfully I found unitag, a website that generates such QR codes easily. The website itself oly generates PNG images, and I needed vector images, so I used their API to generate the SVG. Here is the final QR code which links to my website:
I needed to project this QR code on a cylindrical surface and extrude it. After a bit of searching around, I found this tutorial which did almost what I needed, and I just changed the text to SVG image instead. I had to stretch the image about 10% in the y-axis to make the final curved image square.
I 3D printed the file first, to make sure I had it right.
I then tried it on a wooden dowel to get the process right before milling aluminium.
The result was a pretty nice ink roller.
I finally started milling aluminium and after a few failed attempts with ball nose bits, I got it right with a 1/8″ square bit. I had to modify the 3D file a bit to increase the gaps, so i could do the entire process with a single 1/8″ square end bit.
Here’s the final piece milled
I’m adding the heating elements to make it a wood burner.
This week, I decided to make an aluminum knob for a potentiometer.
The process is pretty simple. I started by mounting a solid aluminum blank on the three jaw chuck. I faced the blank, turned it to a cylinder and then flipped it. Faced and turned the second end as well, and the blank was ready to shape.
I turned about 20mm length from the end down to 16mm to make a top hat kind of shape. Then I drilled a center hole on the tail end of the workpiece. I drilled a 6mm hole to accommodate the potentiometer.
I sanded the piece with sandpaper and scotch-brite. Then I cut it off with a hacksaw and mounted it on the lathe again to face and sand the bottom.
For this week’s assignment, I made a mallet on the wood lathe.
The first step was to glue up plywood pieces and make blanks. I used scrap plywood and as I’d soon find out, this was a very bad choice.
I started with the head of the mallet. The first step was to round the blanks. I used a round nose tool and sharpened it often. For the most part, the process went smoothly, but a few big chunks of wood did separate from the ply and hit the face mask. This is why you wear a face mask, people!! And this is also why we don’t use the cheapest ply on a lathe.
The stock was much larger than needed so I cut out a smaller piece with the parting tool. I shaped the work free hand.
The mallet head needs three holes, one to accept the handle and two smaller holes to accept pins which would retain the handle. The holes should be centered and that’s why we need this drill jig. I tried to make the jig out of plywood a few times, but a single plywood piece turned out to be too difficult to work. The tool tended to bite into it and stopped the piece from rotating. I tried cutting the piece beforehand to shape it roughly and reduce the material needing to be removed. But it would splinter at the chuck or just break at the tool. I finally used a small stock of soft pinewood instead.
With the the jig in place, I indexed the lathe and drilled the holes. For the handle, I chose 1.25″ spade bit.
The handle was shaped freehand out of plywood as well. I had to remove the handle from the lathe to check the fit to the head often. A few times the handle got removed from the lathe while turning. I think this was because I tightened the tail only before starting the lathe. When I started the lathe and used the tool, the torque would make the chuck bite into the wood more, and that would loosen the work at the tail. I had better results when I tightened the work one more time after starting the lathe and stopping it again.
After turning the handle, it was just a matter of gluing up the handle, drilling holes to hold the pins and gluing the pins in.
A quick buffing session later, the mallet is ready!
I love wood working, so I was very excited to get started with the lathe. But even for a first project, I think making a simple handle is a bit boring, so I decided to try adding an off axis step as well. Here’s a step by step guide of what I did-
I started with a soft wood dowel, marked it’s center and mounted it on the lathe. I used a round nose tool to shape the bulk of the handle, using my fist as a reference and free handing the design. I left the handle fatter than needed for now. And trued up the ends.
I then sanded down the sides at a ~5 degree angle on the sander and mounted it on the lathe in this angled configuration. I started the lathe at a slow speed and rounded the ends so that the weight wasn’t too unwieldy. Then I shaped the fat part of the handle, again using my fist as a reference.
When I was happy with the shape, I took the handle off again and mounted it in the original configuration for sanding. If I were to do this again, I would sand the handle in this tilted configuration before dismounting it. I sanded it with 60 grit and 220 grit paper.
I finished the handle with the wax buffing wheel. Here is the finished result-