Next, I started work on the barrel. This will be a hollow cylinder that will house the main spring. The main part of the barrel is made up of three parts. A cylinder and two end caps to keep the spring inside. I’ll start with the end caps, which John Wilding calls Flanges.
I made the flanges from 303 stainless steel. They need to be 2 7/8” in diameter. I chose to make them from 3.25” diameter stainless round rod. I was able to get an almost 2-foot chunk of this large diameter 303 stainless steel from Yarde Metals' drop area for far less than it would have cost me to get even a few inches of smaller bar. So I went with this.
A 22” chunk of 3.25” bar is very heavy! Something like 65 lbs! That’s almost 30 kg for my metric friends. That’s stinking heavy!
I cut a 5” piece off that long bar to make it more manageable, and that chunk was still almost 15 lbs!
Anyway, I chucked that up in the 4-jaw on the lathe, turned about 1/2" of it down to 2 7/8”, then shaped the very end for the flange. After that, I marked where I wanted it cut off (3/16” wide) using a small grooving tool:
Then I took it back over to the bandsaw and sliced off a disk for the first barrel flange. While doing this, I realized I’d meant to drill a 3/8” center hole while it was still centered up on the lathe. Oops… Guess I’ll have to do that later.
After getting both flanges to this point, I mounted my small 4-jaw chuck and centered one of the flanges backward in the chuck. Then I faced off the outside of the flange to make the whole thing 3/16” wide. This is also when I fixed my earlier oversight and drilled the center hole. (I did the second one in the right order, though!)
Next, I drew layout lines on the flanges to represent about where the spokes will be. After centering it up on the rotary table, I used coordinate drilling to put holes in each corner of the cutouts between the spokes.
Here’s my coordinates for the 20 holes (four per spoke, and five spokes). Doing this coordinate drilling seemed like a good idea at the time, but for the second flange, I drilled one spoke with the first line of coordinates, then rotated the RT by 72 degrees and used the same coordinates as for the first spoke (repeating 5 times). This method seemed to keep the holes lined up better for the cutout sessions that come next. But the first method (pure coordinate drilling) wasn’t terrible. Just not as good as the second.
With all corner holes drilled, I rotated the RT to make the right side of the spoke straight with the Y axis (the spokes are tapered), offset the assembly half the width of the spoke to the left, and made multiple passes to connect the corner holes.
I then rotated 72 degrees to the next spoke and repeated the procedure. After completing all five of the right-hand sides of the spoke, I rotated things the opposite direction, changed the X-offset to the opposite direction, and cut the other side of the spoke.
Repeating that around the wheel gave me the edges of the spokes. Then I had to re-center the wheel to make the radius cuts around the hub and the rim. In this picture, I've made all the cuts around the hub but only one section around the rim.
After completing all five spokes, my final operation on this flange is to cut a radius notch to make room for the knot in the end of the cable. I did this with a boring head.
This completes the first flange. The second one is currently in progress – still working on crossing out the spokes.
This is not a quick process for me. It has been several long days in the shop to get this far. Hopefully, one more session to complete the spokes for the second flange. I’ll just keep plugging away.
Kim
