Milling Feed Rate

[aliva]

I have a 9x42 vertical mill with power feed. I was wonder how other people set their power feed rate for inches per minute. IPM
Like most power feeds mine has a variable speed knob., with a forward reverse lever. There are no markings on the knob to indicate speed. I have not measured the speed of the table with power feed set at different positions yet. So how do others set ,their speed, say, 2 IPM or 6 IPM or what ever. Do you run a test and measure travel at various knob positions, then mark the knob position?

Thanks in advance

 

[Wreck™Wreck]

If it is a typical Bridgeport type the lead screws are 5 TPI or .2 per revolution, start a stopwatch and the feed at the same time and count the handle revolutions, when it reaches 5 rotations stop the clock. Note the time that it took to go 1 inch (5 revolutions) if for example this took 10 seconds then the feed is 1" every 10 seconds, 10 X 6 is 60 seconds or 6" per minute, old school. Retime at different speed dial positions and mark them around the dial as you go until it begins moving so fast that counting the handle revolutions becomes impossible at which point a tachometer is required, easy as pie otherwise.

If the lead screws have a different lead adjust the math accordingly, minuets remain the same unless you are using metric time of course.

 

[T Bredehoft]

Best way: hand feed the mill into to the work to get the feel of what it too fast, what is slower than need be. (It's sort of intuitive, you can hear the cut) but it does take experience. Once you have achieved this goal, set the feed of the machine to sound "right." Calculating the thousanths per flute is an ideal, but Ideals are for CNC, where you can set it exactly.
Do it my way, you will either break the cutter, or wear it out. You'll learn.

 

[Wreck™Wreck]

Best way: hand feed the mill into to the work to get the feel of what it too fast, what is slower than need be

This is how I do it on manual lathes or mills, by sound and chip colour, run it hard until the tool fails then slow down from there (-:
However the question was determining the feed rate of an unknown power feed which has had the numbers worn off the dial over time. This may keep him from running the tool into parts at 100" per minute, which is always fun.