Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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


    User Avatar
    Science Advisor

    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


    User Avatar
    Science Advisor
    Homework Helper

    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.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook