Tuesday, December 1, 2015

Onwards with wheel cutting

In the saga of the Isaacs clock , we now go on to the big wheels. There are two 96-tooth wheels, and (I think) a 100 or maybe a 120 tooth wheel, the latter in extreme range of what I can turn on the lathe. I am now making the wheels out of Lexxan instead of acrylic. Acrylic shatters too easily. With our homemade fly cutter it was possible to cut the first 96-tooth gear. Note the masonite backup disk on the wheel, this helps damp out the cutting shock.

So on to the second one. First step is to turn the blank. I try to do a spare, but it is  not a good idea to turn them together because the turning process tends to melt the Lexxan and then you have two welded wheels, which is not a happy situation.

So this gear was (still is) mounted on the dividing head, and I have cut about 8 teeth, but gear cutting is an absolutely frustrating situation and you should only do it when you are wide awake and capable of extreme concentration. So I decided to take a break, and the disadvantage of this is that I will have to "pick up" the cut. So I have only half of the mill available.

Then I decided to take a break. I would make a multi-point cutter. Comercial cutters are made with very large holes. Maybe 7mm. My mill takes a 3mm arbor. So the cutters are a saga all by itself, which will be the subject of the next post.

Cutter-making requires an eccentric arbor. I will explain this more fully in the next post, but it involves turning off-center. But here's a shot of the making of the arbor, in case I forget to include it in the next post.

It has taken a week to get this thing up, thanks to Google for their user-friendly (hostile) interface with blogger. Sorry.

 and one 100-tooth wheel. The 100 toother is going to be a real deal.

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