I am in the process of making a machine for grinding telescope mirrors.
I have a 1/2 hp single phase motor the shaft of which turns at 1400 rpm. I need to reduce this to 40 rpm. I have attached a 1.5 inch 38mm v belt pulley to the motor shaft. I will run a belt from this to a 10 inch pulley from an old washing machine. Will running a belt from a v belt pulley to a flat pulley cause any problems?
This should give me a reduction to 254 rpm according to an on line pulley calculator. On the end of the shaft holding the 10 inch pulley I will put a 75mm, 2.95 inch v belt pulley (aluminium).
My next question is what material should I use for the shaft, it needs to be 19mm in diameter to fit the v belt pulley? Steel? If so which steel? I need to be able to cut a keyway in the shaft with my mini mill.
The third question is which bearings should I use? Pillow block bearings seem the easiest, but they are rather expensive. The bearings are going to be attached to a wood frame, could I just drill holes in the wood and push the bearings in to it, making sure they fit tightly?
From the 75mm pulley a belt will got to a 15 inch diameter pulley. This will be made out of two discs of 18mm thick birch plywood, glued together, both chamfered at 45 degrees to form a v. What is the best way of attaching a shaft to this wooden pulley?
At the other end of the shaft will be the 22 inch diameter turntable for the mirror. This i have already made (I have already made a very heavy duty table as well). The turntable is made from 2 discs of 18mm plywood glued together and varnished. What is the best way to attach the shaft to the turntable and how thick should the shaft be and of which material?
I should end up with the turntable rotating at 40.1 rpm
I know I am asking a lot of questions! This is actually a very simple machine, but I do not have an engineering background and this is the most complicated mechanical thing I have tried to make!
David