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I think my mill power feed may be a failure...

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  • I think my mill power feed may be a failure...

    .... or at least a semi-failure.

    I got a nice case made to cover the motor, the worm and wheel, the dog clutch and to mount a couple of controls. Actually, I was rather pleased at how the dog clutch panned out as that is my most complex milling project so far.

    But I seem to have messed up somewhat in my choice of speeds as the slowest I can move the table is one inch per minute (a tad less, 24.3mm in fact). This seems fine for fly cutting aluminium but I have a feeling that will be too fast for work on harder metals such as steel?

  • #2
    One inch per minute is way slow enough. I never cut that slow.

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    • #3
      There will be some situations where that isn't slow enough. In particular, any sort of cutting with very small cutters, 3mm and below, especially solid carbide cutters.
      Free software for calculating bolt circles and similar: Click Here

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      • #4
        Your anti-gloat is meaningless without pictures!

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        • #5
          Macona, Evan, thanks, it was the small diameter cutters that I was afraid of breaking through feeding too fast and unfortunately my mill does not have a high spindle speed with a maximum of 2800 plus changing the belt speed is a real pain, in fact I have never used the highest speed so I guess I will need to make myself a little stool to reach those dang pullies!

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          • #6
            Originally posted by dp
            Your anti-gloat is meaningless without pictures!

            Ouch!..............

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            • #7
              Originally posted by dp
              Your anti-gloat is meaningless without pictures!

              Ouch!..............


              IMGP9632 by MrJohnHill, on Flickr
              General view...




              IMGP9631 by MrJohnHill, on Flickr

              Cover off showing the dog clutch.






              IMGP9629 by MrJohnHill, on Flickr
              I took a panel off the mill base and fitted the power supply in here, there is room for further developements.
              Last edited by The Artful Bodger; 02-04-2012, 04:52 AM.

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              • #8

                IMGP9628 by MrJohnHill, on Flickr


                Shows worm and wheel.



                IMGP9627 by MrJohnHill, on Flickr

                The cover is back on..

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                • #9
                  Looks to me like a DC motor ? If so what about fitting some electronic speed control ?
                  .

                  Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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                  • #10
                    Only 2800 on that big of a mill?. That is kind of surprising. If it has a three phase motor you could overspeed it to at least 4200 like most R8 knee mills, they all use the same bearings.

                    ME Consultant gives me about 4ipm for an 1/8" 3 flute carbide end mill at 2800 RPM. I have found the main thing with little end mills is getting the chips out. That's what causes the most broken end mills for my and why I added a second mist head to my mill.

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                    • #11
                      ME Consultant gives me about 4ipm for an 1/8" 3 flute carbide end mill at 2800 RPM.
                      That depends entirely on what you are cutting. In steel that size bit could easily be run at 8000 rpm. Running at the calculated maximum chip load with those bits is a good way to break them. I do a lot of work with small cutters and most of them end up broken before they wear out. Since I am using CNC I know the cutting rates are accurate.
                      Free software for calculating bolt circles and similar: Click Here

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                      • #12
                        Originally posted by John Stevenson
                        Looks to me like a DC motor ? If so what about fitting some electronic speed control ?

                        Exactly........ In fact, did we not have a discussion about that only a little while ago?


                        http://bbs.homeshopmachinist.net/showthread.php?t=52082
                        1601

                        Keep eye on ball.
                        Hashim Khan

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                        • #13
                          I don't think I have ever cut as slow as 1 ipm. 3 ipm is usually where I start and work up from there. Even with slabbing mills I cut faster than that. I could see the need with tiny cutters and low rpm in tough materials you might need it, I just don't do that.
                          James Kilroy

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                          • #14
                            Originally posted by John Stevenson
                            Looks to me like a DC motor ? If so what about fitting some electronic speed control ?
                            Thats in the programme John but it will have to wait until I get to the 'big city', 50 mile drive. Meanwhile I am using PWM generated from the serial port on a PC but I dont want to always do that, or I have to get organised and incorporate a an old PC in a convenient fashion.
                            Last edited by The Artful Bodger; 02-04-2012, 03:57 PM.

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                            • #15
                              Originally posted by J Tiers
                              Exactly........ In fact, did we not have a discussion about that only a little while ago?


                              http://bbs.homeshopmachinist.net/showthread.php?t=52082

                              Yes we did and thanks to all those who gave advice, I have been using a PC to generate the PWM but that is rather incovenient, the plan is to build a knob controllable PWM when I can get the bits.

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