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Chuck speed of a lathe

  1. Feb 26, 2008 #1
    Hi, i would be grateful if anyone could help.
    When using a lathe to cut a spindle of 10mm diameter at a cutting speed of 45m/min, how would i convert the 45m/min into rev/min and rad/s?
    Also how would i covert the cutting speed of 45m/min into mm/s for a spinde of 7mm?

    Thanks :rolleyes:
     
  2. jcsd
  3. Feb 26, 2008 #2
    So, the spindle is 10 mm diameter. The circumference is thus 31 mm or 0.031m which is 0.031 m/revolution. Then 45 m/min divided by 0.031 m/revolution gives 1450 rpm. Note that, as your tool goes into the spindle, the surface speed will decrease as the diameter.
     
  4. Feb 26, 2008 #3

    FredGarvin

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    This question is posed rather strangely. The 45 m/min looks like a feed rate. It appears that the OP needs a depth of cut number. I'm probably misunderstanding the problem.
     
  5. Feb 26, 2008 #4

    NateTG

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    I think this is just a conversion problem:
    1 revolution=2 [itex]\pi[/itex] radians
    1 diameter = 2 radians
    1 minute = 60 seconds
    1 meter = 1000 millimeters

    Now, in this problem
    1 diameter = 10 mm

    So - to get from meters per minute to revolutions per second:
    45 meters/minute * (1 minute/60 seconds) * (1000 milimeters/1 meter) * (1 diameter/10 millimeters) * (2 radians/1 diameter) * (1 revolution/ 2 [itex]\pi[/itex] radians)

    Each of the fractions is 1, and you should be able to cross off the units. Regrouping gives...
    (45 * 1000 * 2) revolution / (60*10*2 [itex]\pi[/itex]) seconds.
     
  6. Feb 26, 2008 #5
    I think (hope) that he was asking for cutting speed in surface m/min cause that's how I answered. It sounds about right for free machining low carbon steel (~150 fpm). OP, help us out. But, yes, he sorta asked it backwards of the way you normally hear it, so I'm not sure.
     
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