Things have been moving along nicley and I'm learning all sorts of new things from this project. The Victorian requires a pair of spur gears with a ratio of 2:1. I considered several options to supply them and friends like Tim (Zuesrekining) graciously offered their help, if needed. The options ranged from a simple online order (to easy) to having a local friend cut them (involute cutters are damned expensive). I finally chose to cut my own gears using Duclos' instructions for single tooth cutting technique. Thanks go to George Seal for pointing me to the references in his first book.
I recently acquired a small rotary table, complete with an indexing plate, neither of which I've used until now. It's too small for much serious work, but the MT2 taper was perfect for using my tail stock drill chuck to hold a mandrel, so onto the mill table it went. Things were a little crowded with both the vise and the RT, but it was workable.
After cutting a practice gear in aluminum, it was time to get serious. The cam gear blank was mounted and the first cut was begun. It would require several passes of 56 cuts, so patience was the order of the day. The tiny cutter is shown mounted in the flat angle fly cutter I made up to hold the tool. The blank has just begun to receive the first round of cuts. The cutter mimics an involute cutter but is less critical than required for the high level of accuracy of what are rather expensive commercial cutters. (one quote was $120.00 for the needed pair)
As thing progressed, making the gears was proving to be feasible. The photo below shows the gear getting it's second pass. There were two gears to cut, one with 56 teeth and another with 28.
The gears were on and off the mill several times for testing and then returned to fine tune the cuts. I mentioned patience.... the excitement sags a bit after 5 or 6 times around a 56 tooth gear. The routine of make a cut, reset the hole count scissors on the RT, lock out the indexing pin, count off the complete turns and then settle the indexing pin in its new hole.... well you get the picture.
Here is the almost final test fitting. I say final because this is where the first required remake of a part came about. Just after this photo was taken I moved the small gear back to the mill to take off another .003 inches to chase away the last of the binding between the pair. 3/4 of the way around the blank I managed to drop count on the completed turns of the RT and planted the cutter dead center of a tooth. Scratch one gear. It was SOOOOOOoooooo close to being finished. Nope.... no throwing, but I did vent a bit. At least it wasn't the cam gear. That one would have really hurt. Tomorrow, I'll cut a new blank and go back at it.
The photo below shows the gears and the cylinder's new water jacket. (thanks Tim... your help with the arbor press was a life saver) The cylinder head is likely to be the next major project, along with the piston and the idea I've gotten for con rod.
Steve
