The main wheel is made from 1/8" leaded brass, which is thicker than it will be in its final form. The extra thickness will permit cutting in a pocket which will contain a hidden ratchet wheel.

The wheel is 2.347" OD, and it has 120 teeth. The teeth are Module .45, or about 0.0030" wide with a 0.030" gap. The wheel was cut using one of my homemade fly cutters. I've used this very cutter to cut all of the wheels in five different clocks. Making it was well worth the time!

Following my usual practice, the wheel blank was mounted on an arbor, trued and cut to size in the lathe on centers, then mounted in my homemade wheel-cutting fixture, which has also served well when making many clocks.

The fixture arbor is threaded with 1/4" NF on both ends -- one to hold the wheel blank, the other to clamp on the index plate. There is a hole for a "tommy bar" in the middle of the arbor to permit insertion of a punch so that the 1/4" NF nuts can be screwed on nuts on tight.

The indexing fixture has a horizontal slot cut into the front hole. There is an adjusting hex head set screw to clamp it -- this permits adusting the front clearance to zero, while permitting free turning. There is a hollow screw with a hex locknut on the back fixture hole. This permits adjusting the "endshake" of the arbor to zero, as well. This is a feature I've never seen in any other fixture. This makes for a rigid fixture, whose arbor still turns easily.

The series of holes in the index plate were drilled with a Sherline rotary table. The lever which holds the pin inserted in the holes is made from an old hacksaw blade.

Todays' links:

Mainwheel cut
Fixture, showing back nut and front slit.
Fixture on mill
Fixture on mill 2
Fixture
Fixture drawing (DeltaCad>