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New powerfeed for lathe - DC variable speed

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  • #16
    Thanks for the feedback. I'll have to give a power supply a go just for long term ease of use and wiring cleanliness. To those mentioning a switch on the carriage keep in mind that this motor drives the rod, but the carriage mounted lever still engages longitudinal or cross feed, so that's unchanged. A slick switch setup for a stop has crossed my mind and I may play with that, but I'd be more apt to work on something with the VFD for threading to a shoulder. Feeding is easy enough to come close and then hand feed.

    The disconnect between feed and spindle speed is certainly a disadvantage at this point, but the lack of gear noise and wear is just awesome. The belt drive machines are so quiet and smooth until you engage that gear train, and then it's a racket, really discouraging using it at all. I actually think the gear train adds some vibration/harmonics which impact finish too, I'm getting really great finishes with this setup. As has been said if I really wanted to know I could calculated the in/rev and make a table. The LED display is voltage but it doesn't work at the lowest speeds for some reason, it flickers. I've found it's pretty easy to judge just by watching the handwheels spin before getting into the work. For a roughing cut I dial it all the way up, and for a finishing I slow it down, then watch the chips.

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    • #17
      Hi All
      my setup uses similar setup with a "Poly Vee" belt with just enough tension to drive the Lead Screw and use a fixed stop that allows the belt to slip when turning up to a shoulder. Slip the belt off and engage the gear train for screw cutting.

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      • #18
        Originally posted by JCByrd24 View Post
        For a roughing cut I dial it all the way up, and for a finishing I slow it down, then watch the chips.
        Where will you set it when parting 304 stainless?

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        • #19
          Originally posted by Mike Amick View Post
          Also .. on my lathe if you find that your not happy with the speed you have selected, you
          have to stop the lathe to change it. With your's, you can fine tune it on the fly, sounds
          like an advantage to me.
          yep.. me too! Another toy I'll have to build.

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          • #20
            Originally posted by J Tiers View Post
            It DOES give the cut per tooth on the mill, which can be quite useful to know.

            On the lathe, it will again tell you the chipload, and will help when wanting fine finishes.

            Can you "by guess and by golly" that stuff? Sure, you certainly CAN. Sometimes it does lots better if you use at least a decent stab at good numbers
            Hi,

            I have yet to see an electric powerfeed on a manual mill that can tell you what the exact feed rate is. Certainly Servo brand and it's clones don't. And if you cannot get a good sense of your feed rate by eye, you are pretty green indeed.
            If you think you understand what is going on, you haven't been paying attention.

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            • #21
              Originally posted by dalee100 View Post
              Hi,

              I have yet to see an electric powerfeed on a manual mill that can tell you what the exact feed rate is. Certainly Servo brand and it's clones don't. And if you cannot get a good sense of your feed rate by eye, you are pretty green indeed.
              Does not come up for me, since I do not have power feed on the mills. So I do it by feel and chip type.
              CNC machines only go through the motions

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              • #22
                I don't have mill power feed either. When I'm concerned about chip load I look up the IPM and simply count off the seconds. My mill feeds .20 per rev, so 1 IPM should have me turning the wheel once every 12 seconds. 2 IPM = one rev every 6 seconds, etc.

                For a fine finish on my lathe, I just make sure the feed per rev is a fraction of the radius on the cutter. It's easy to see if you are leaving grooves that need a slower feed. I can do a good, clean, smooth manual feed for most of an inch, then there is always a spot where it's obvious that I paused.


                Dan
                Last edited by danlb; 04-15-2018, 11:53 PM.
                At the end of the project, there is a profound difference between spare parts and left over parts.

                Location: SF East Bay.

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                • #23
                  Originally posted by JCByrd24 View Post
                  . . .To those mentioning a switch on the carriage keep in mind that this motor drives the rod, but the carriage mounted lever still engages longitudinal or cross feed, so that's unchanged.. . .
                  And? If the rod stops, the feed stops so are you saying that the switch won't work?
                  Southwest Utah

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                  • #24
                    Originally posted by danlb View Post
                    .....
                    For a fine finish on my lathe, I just make sure the feed per rev is a fraction of the radius on the cutter. ....
                    Dan
                    BINGO.

                    Dan has provided the reason for having at least a rough idea of what the feed is. While yes, you CAN obviously do trial and error, it seems so simple to work out a few settings and know going in that you are in the area you need to be in. It just makes sense.

                    Why would anyone argue AGAINST that? Some others seem actively OPPOSED to knowing the feed, which makes no sense to me. A little testing, and you have the numbers.

                    The manufacturers DID put the numbers on the QCB chart, and milling machines that have built-in power feed usually have dials showing the feed, which they did not put on there just as an artistic design.... I am not talking about cheap chinese stuff, but industrial equipment.

                    To each their own. I would have a chart up for those times when I did care, and for everyday use as well.
                    CNC machines only go through the motions

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                    • #25
                      Dials showing the feed? How about 1-10 on the most popular mill types ? Actual feed numbers are great for cnc, but on manual machines?

                      Reminds me of a quote : "Knowledge comes from reading; experience come from observation"; you figure out your feeds real quick, and rarely by timing or counting.
                      Last edited by lakeside53; 04-16-2018, 01:04 AM.

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                      • #26
                        Originally posted by lakeside53 View Post
                        Dials showing the feed? How about 1-10 on the most popular mill types ? Actual feed numbers are great for cnc, but on manual machines?

                        Reminds me of a quote : "Knowledge comes from reading; experience come from observation"; you figure out your feeds real quick, and rarely by timing or counting.
                        While I can't say you are wrong, we are home shop types. Sometimes months pass between using a particular machine. I can't trust my memory of what feels righgt, so I need charts of speeds and feeds to get close to the right settings. Sort of like the way welders use charts (based on past experience) or approved WPS (Welding procedure specifications) to make sure that the weldment will be right on the first try.

                        I no longer try to remember all the formulas and constants that I use in the shop. Two mills, two lathes, several welders, Many power saws and you expect ME to remember the proper settings for anything? Not going to happen.

                        Dan
                        Last edited by danlb; 04-16-2018, 12:42 PM.
                        At the end of the project, there is a profound difference between spare parts and left over parts.

                        Location: SF East Bay.

                        Comment


                        • #27
                          Originally posted by lakeside53 View Post
                          Dials showing the feed? How about 1-10 on the most popular mill types ? .....
                          Machines with gearbox feeds.... large industrial mills, not a Rong Fu with an add-on PWM feed box.
                          Last edited by J Tiers; 04-16-2018, 02:15 AM.
                          CNC machines only go through the motions

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                          • #28
                            oh.. so now you redefine your statement to mills that are not typical HSM? This entire conversion started about dc drive non-synchronous power feeds, not gear feeds!

                            BP are not Rong Fu, and probably the most populous "real" mill after clones are counted. Many in HSM hands. Servo Power feeds and its clones are 1-10. Rong etc.. likely not much different
                            Last edited by lakeside53; 04-16-2018, 02:18 AM.

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                            • #29
                              I am sorry. I did not read everyone's post. I did see some. I only have two lathes that I can play with, My 40's south bend and my 40's monarch.

                              Two completely different machines.

                              My SB is my go to lathe. My 10ee is a lil scary to be honest. The power.

                              She is good for everything within her short range.

                              Its like the smoothest sewing machine.

                              You can dial her down to 55RPM or smoothly ramp it up to 4000RPM.

                              She is such a big butted girl she does not move at 4k.

                              At 4000 RPM the 10ee still sounds like it turned off. Its the wind noise from the chuck that gives it away.

                              I am not kidding. If you get a chance to drive a 10EE do it.

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                              • #30
                                Originally posted by chipmaker4130 View Post
                                And? If the rod stops, the feed stops so are you saying that the switch won't work?
                                It'd work fine, but it was mentioned in the context of having to reach to my switch at the tailstock end to stop the feed, which isn't true. The factory feed lever on the apron still does that, similar to if using the original power feed through the gear train. So there is no gain from mounting that switch on the apron.

                                Some sort of stop/microswitch setup that stops the feed at a shoulder or something was also discussed, and that would be an added capability.

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