With the button tool ready, next up was to make my gear cutter blank. For this, I used 1” round W-1 tool steel. I was going to feed it through my 1” collet, but turns out, 1” material won’t ‘feed through’ the 1" collet. The threads on the inside are just a mite too tall to allow a 1” piece of stock through.
So instead, I cut off a thin slice with the horizontal bandsaw (probably easier than using a cut-off tool anyway) and then set it up with my little Taig 3-jaw chuck to face off the slice. I then flipped it around and brought it to the correct thickness.
Next I drilled and reamed a 3/8” hole to fit on the arbor I just made (“just”, being about a month ago ).
Here’s my gear cutter blank:
Then I put it on the 3/8” arbor, mounted it in the lathe, and cleaned up the circumference to make sure it was true.
Here’s where the fun begins! I used the button tool to cut one side of the cutter, going in the exact, specified depth.
Then moved to the other side, the exact specified amount, and made a second cut; again going in the exact specified depth.
Forming the cutter with a single button meant I had to make two cuts, but I only had to make one button. And with one button, I can re-use the button tool holder. For a two button tool, I can’t share the holder because the distance between the buttons will be different for each size button. I’m not sure I see much advantage in making the two button tool. Maybe others can tell me why that would be more desirable?
With the tooth form created in the tool blank, I put the arbor in the square collet block and took it to the mill to cut the teeth.
As you can see, I cut four teeth. I know others cut 8 or more teeth, but that seemed harder, and I wasn’t sure there would be a lot of gain for a minimal use tool, and it would be more teeth to relieve. So I went with four.
And here I’ve just filed some relief on the back of each tooth, trying ever-so-hard to avoid the fronts of the teeth! I didn’t want to damage those!
With the cutter shape completed, I heat treated and tempered it (no pics, but no burnt fingers this time either!
). And here’s the finished gear cutter:
Now it gets even MORE fun! Mounting the gear cutter back in the arbor – being careful to put the cutter in so the business end hit first – I setup the RT and went to work on a scrap piece of 3/8” brass from the junk bin.
Stupid me, I forgot to tighten the collet, so the gear blank slid.
It didn’t really become noticeable till I’d gotten ¾ of the way around and realized that it looked all wonky:
So I stopped that test run, and tried again with another bit of scrap brass. I carefully tightened the collet and set to work on this one. I was feeling pretty pleased about it till I took it out and looked at it end on. The one on the right is the first one – the teeth look tolerable endwise, but they were a little wonky along the length. The one on the left, my 2nd try, the teeth are all pointing in a strange direction. I must have goofed up the Z-axis when I was changing blanks. I don’t know why I didn’t lock the Z-axis down, but I didn’t. I clearly should have!
With that minor fiasco, I called it a day and went in. This brings us up to the end of LAST week’s work. It was clearly time to go in and get my mind on other things for a while.
A week later...
After thinking about all my gear making problems for a week, I went back out to the shop today to try again. This time, I decided to go for it and try the real gears. So I cut a longer piece of brass to use, and drilled a support hole on the far end this time. I also spent more time squaring up the RT. That took an inordinate amount of time because the first piece of rod I was using was bent. When I got a straight piece, it went much better!
Here we’ve just finished cutting 16 theeth, all around the gear blank.
Following the tooth cutting, I went back to the lathe, drilled and reamed a ¼” hole for the drive shaft, and cut off the outer 1/8” or so (since that portion only had partial teeth).
And then parted off two ¼” lengths for my drive gears.
After a little clean up, this is how they look.
Not too bad for my first set of gears
. Now I’m trying to figure out how to mount these puppies. A set screw won’t have enough meat to bite into, and it would mess up the gear teeth anyway. Maybe I have to solder it to the shaft. We’ll work on that next.
By this time, it was too stinky hot out in my garage to continue working. We’re having a heat wave up here in the great northwest, and I'm not built for heat! So, I called it a day and went in.
Thanks for stopping by!
Kim
