The machinist's handbook confuses me about speeds and feeds. I have a vertical turret lathe. I have options of feed rates at .010", .016", .021", .032" (inches the feed will move the tool per 1 revolution) and I have options of speed, not a variable speed spindle, of 42 rpm, 57, 78, 102, 127 rpm. I am machining low to medium carbon steel, 1020 steel. I plan to take a .200" depth of cut, and the o.d. of the part is 36".
The "handbook" jumps into surface feeds, but I don't know how to arrive at that.
What I would like to know, is a simple formula, with the given information above, to calculate the following:
1. A formula for calculating Optimal rpm of the vertical turret lathe spindle/table.
2. A formula for calculating Optimal feed rate for the rpm chosen.
3. Knowing those two items, a formula for calculating the surface speed at 36".
Please show me examples, I'm slow to learn, but once I learn it, I've got it. And how do I relate this to drilling and milling machines.
Thanks,
Bob Bussey Jr.
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