AndyStobbs
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- Messages
- 2,475
- Location
- North West England
I'm good at maths, and am pretty certain I'm not missing something obvious here but two heads are better than one, so a forum's worth has to count for something.
I have an old flywheel here, I looked at and saw the basis of a rotary table. I was thinking I could turn a worm screw on the lathe to drive it. So...
Its 135T, 11.250" PCD and I reckon that works out to 12DP - actually its probably metric and using the module gear system but that doesn't matter for now.
Right so 360 degrees / 135T = 2.66666667 degrees per tooth.
For simplicity I thought it would be nice to have one turn of handle (at this point I envisaged the handle direct onto the worm) generating 1 degree of rotation. But the numbers got scatty, the angular movement of the 'table' at the OD was 0.098......" for a 1 degree movement, so it'll be impossible to cut a screw that'll create that amount of rotation in one turn - on an L5A at least.
However I got thinking the other way around and 0.375T = 1 degree, thats a nicer number, so I started thinking about how I could index 3/8 of a tooth, and at this point I got to the handle being indirectly connected to the worm,through gearing instead. So a gear system that can generate a reduction such that 1 turn in = 3/8ths of a turn out with a multiple of 8 teeth should work. Depending on worm pitch, which has to be quite a small number due to the sheer size of a starter ring gear.
Am I mad or am I crunching correctly?
I have an old flywheel here, I looked at and saw the basis of a rotary table. I was thinking I could turn a worm screw on the lathe to drive it. So...
Its 135T, 11.250" PCD and I reckon that works out to 12DP - actually its probably metric and using the module gear system but that doesn't matter for now.
Right so 360 degrees / 135T = 2.66666667 degrees per tooth.
For simplicity I thought it would be nice to have one turn of handle (at this point I envisaged the handle direct onto the worm) generating 1 degree of rotation. But the numbers got scatty, the angular movement of the 'table' at the OD was 0.098......" for a 1 degree movement, so it'll be impossible to cut a screw that'll create that amount of rotation in one turn - on an L5A at least.
However I got thinking the other way around and 0.375T = 1 degree, thats a nicer number, so I started thinking about how I could index 3/8 of a tooth, and at this point I got to the handle being indirectly connected to the worm,through gearing instead. So a gear system that can generate a reduction such that 1 turn in = 3/8ths of a turn out with a multiple of 8 teeth should work. Depending on worm pitch, which has to be quite a small number due to the sheer size of a starter ring gear.
Am I mad or am I crunching correctly?