Thanks for the info, Bob.
I just recently made a round knob for a bracket I had made earlier. I made an arm for the bracket that would swing, and I needed an easy way to lock it down without having to go find a wrench every time I moved it. The knob is about 2" in diameter with a 5/16" threaded hole in the center. I produced a whole lot of aluminum shavings trying to figure out the best way to make it and finally came up with this method:
1. Mounted a piece of 1 1/2" aluminum in my 12" rotary table that had already been centered on my mill. The aluminum stock was a piece of scrap that had sufficient 'wings' which I could use to clamp onto the rotary table.
2. Drilled and tapped the 5/16" center hole.
3. Used a 1/2" course roughing end mill to mill the circle about 1/8" over the final diameter. I milled to about an 1/8" shy of going through the entire 1 1/2" stock.
4. Removed the 'wings' and chucked the part in my lathe using the threaded hole to mount onto a make-shift arbor. The rough section where the 'wings' were removed was toward the BACK of the chuck.
5. Milled a shoulder about 3/4" deep and 7/8" in diameter.
6. Went back to the rotary table and mounted and centered a 3-jaw chuck on it.
7. Mounted the part in a hex collet block with a 7/8" 5C collet; then mounted the whole contraption onto the chuck.
8. Used a finishing end mill to clean up the shoulder.
9. Now comes the fun part: mounted a 1/4" finishing end mill and moved the table in 1/8" from the shoulder.
10. Milled a 'half-hole' every 30 degrees, resulting in a 12-point 'serrated' knob. (I'm sure there's a more technical term for this, but I don't have a clue what that might be.)
11. Took the knob back to the lathe, rounded over the edge and, using the compound slide, milled a slight taper on the face of the knob.
12. Still have some sanding and polishing to do, but it turned out pretty nicely. (See the pix below.)
Now for a question: That was a lot of work!!! The entire time I was making this part, I found myself declaring there has got to be an easier way to do this. How would you go about making such a part? Which, if any, of the tools you described could have eliminated some steps and streamlined the process?
Long winded, I know, but hopefully it's understandable.
Regards,
Terry
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