Last December I started thinking about joining TechShop, so at Hanukkah I told my girlfriend that if I joined I could make her all kinds of dreidels. Today I found myself with some extra aluminum, so I decided to use their metal shop make my first one.
Step 1: Cut a Square Out of Bar Stock
The barstock I had was 1"x3" 6061, so I first needed to make a 1"x1"x3" rectangle. Measure the thickness of the bar now; you'll want to match it exactly when you make the square. In my case the bar was 1.016" thick, and that's the size I wanted to match in the other dimension.
We're going to face the bar stock to make sure it's both the right size and perfectly square. However, it's easier to be precise when you have a the whole bar to clamp in the vice, so I'd recommend facing one end of the bar before you cut it. This is an extruded bar, and the sides are remarkably square, so the only sides I need to worry about are the ones I (or the factory) cut.
Carefully measure and cut a little wide so you have material to trim off. I used the horizontal band saw.
Finally, stick an end mill in a milling machine and get the remaining side nice and square at your desired thickness (1.016" in my case). Be careful! If you take off to much you'll have to rotate it and introduce more likelihood of un-squareness.
Step 2: Center Your Stock in the Lathe
The poor man's way to measure while doing this is to scribe an X from corner to corner of the end to find the true center, and put the live center on your tailstock very close to the end so you can see if it lines up with your scribe marks.
The slightly nicer way to do this is to use a dial indicator to measure how far each side is away from it's opposite.
The key it to make small adjustments, and really really try to get it as accurate as possible -- it will help your dreidel spin better!
Update: Here's a good tutorial on how to center your work in a 4-jaw chuck. Some of the tips here would have helped me:
Step 3: Cut the Bottom of the Dreidel
Set your compound rest to the angle that you want on the bottom of your dreidel. I picked 45 degrees, but in hindsight that seems a little steep (it put the center of gravity too high); doing it again I'd probably pick 60 degrees. Use a left-hand cutter and set yourself up on the back-side of the lathe; this will allow you to get the angle you want without running into the chuck. In order to get back there you'll probably have to push you cross-slide almost all the way in. Starting with the back corner use the top slide to start shaping the piece, coming back towards center and moving the carriage a teeny bit left between each cut. To get a nice finish make sure to end with a nice, slow, finishing pass at high speed (~9000 for me).
Step 4: Cut the Handle
Once the bottom is finished you'll have to turn the piece around which means another round of 4-jaw-adjusting, but you can minimize the error by just loosening two jaws, and doing so as little as possible.
If your stock is longer than you want it, you can save a little time by using a parting tool to cut it down to handle-length.
Now switch to a right-hand cutting tool and use facing cuts to trim that metal around the handle to the same length. If you want a slight bevel to the top of your dreidel, angle your cutting too slightly to the right.
Step 5: Engrave the Letters With a Tormach
I used a 1/2" 60 deg V mill, cutting to a depth of 1/16", mostly because I didn't trust myself not to break any of the tiny mills I had available. This only worked okay; I did both pocket and profile cuts (on-line) for each letter, but the thin features were too small for a pocket. This meant that in those thin features there was a thin strip of aluminum that didn't get cut (between the two profile cuts) that you'll have to manually file out.
Attached are the VCarve Pro files I used. If you want to make your own the easiest way is to import bitmap images of the letters and trace them.
Finally, file the letters as necessary, bevel the corners, polish it up, and spin the dreidel!
- Measure the positioning of the letters on the side better than I did -- I estimated a little bit and ended up with the letter s running a little high.
- Use an appropriate mill to get good-looking letters.
- Make a short dreidel! Mine looks good, but is a little too top-heavy to spin really well.