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New powerfeed for lathe - DC variable speed

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  • #31
    Originally posted by lakeside53 View Post
    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
    Don't start with me, dragging the discussion off on a tangent. Those are what I was referring to to begin with.... And not because YOU have one, but INSTEAD because evidently THOSE MANUFACTURERS thought it was useful to know the feed rate. It's called an example.....

    If they thought so, why do YOU insist that it is BETTER NOT TO KNOW the rate? You evidently need to go to some graveyards and tell those folks how stupid they were!

    If you like to remain ignorant of the speed, and just judge it by eye and call it good, go right ahead.... I don't care what you do in the privacy of your own shop.

    Some of us do things differently, either because we do not use the machines enough to remember everything, or because we like to avoid trial and error, so we go by the tried and true speeds and feeds when we need to get it right..

    It ain;t worth wasting the electrons to argue over it..... I brought it up because the OP mentioned not knowing the feeds....so I suggested a way to know them. I'm not telling YOU what to do.
    CNC machines only go through the motions

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    • #32
      Originally posted by J Tiers View Post
      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.
      Hi,

      So, you are straight up guessing too?
      If you think you understand what is going on, you haven't been paying attention.

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      • #33
        Originally posted by dalee100 View Post
        Hi,

        So, you are straight up guessing too?
        Guessing didn't work well....

        I can judge the approximate rate on mill by counting turns.... not "guessing", more "getting reasonably close". I'd rather have a power feed, but so far have not got to that priority on the list.

        Feed on the lathe is trickier, but again, can judge the rate per handwheel turns 1 turn is an inch and a quarter.... REALLY would like to do that differently, but it is what it is.... not down to that point on the list. Might do a slow feed handwheel.
        Last edited by J Tiers; 04-16-2018, 01:35 PM.
        CNC machines only go through the motions

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        • #34
          What's the fascination with knowing the exact feed rate number?I don't think anybody here is suggesting that you close your eyes and smack the feed lever to whatever, so it's not like anybody is preaching that it doesn't need to be known at all. Seems like the observation is that you can get all the information that you need from how the tool is cutting, rather than having a fancy chart set up saying that you're at EXACTLY .9845ipr.

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          • #35
            Originally posted by epicfail48 View Post
            What's the fascination with knowing the exact feed rate number?I don't think anybody here is suggesting that you close your eyes and smack the feed lever to whatever, so it's not like anybody is preaching that it doesn't need to be known at all. Seems like the observation is that you can get all the information that you need from how the tool is cutting, rather than having a fancy chart set up saying that you're at EXACTLY .9845ipr.
            Nobody WANTS to know it like that...

            It's handy to know the cut per tooth, and that suggests knowing the IPM within maybe 30%..... Motors slow down under load, etc, etc, so you will not get a lot closer than that anyway.

            Industrial folks use the IPM to set up a "process" and know that they will get a certain finish quality from that. They probably want to know it within 10%. You seem to think folks want to know within 0.01%.... why would you think that?

            Nobody is telling you what to do, why don't you just let it go......?
            CNC machines only go through the motions

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            • #36
              Originally posted by dalee100 View Post
              Hi,

              Go to monsterguts.com, order a 2 speed 12VDC wiper motor, head over to eBay and order a 6A power supply for less than $10, PWM for less than $10, same for a DPDT switch. Build a box and adapter to drive your lead screw. You now have a $300+ power feed for less than $40.

              This will also work for a lathe. If not knowing exactly how many inches per minute your mill feed is running is no big, why would it bother anyone to know about exactly what inch/rev a plain lathe feed is doing?
              That's a great plan. Thanks for the item list. Sadly such a project is down around #24. But I promise to post it when it happens.

              JCByrd24, good reminder about the lever on the apron I'd still like at least the speed dial to be remoted to the apron though. Just easier to dial a cut from that point with a short reach since the cutter is attached to the carriage. But you're right in that it could just be running the drive rod the whole time.

              All in all though I think I'd still include the three position FWD-STOP-REV switch at the same box as the dial. I like the idea of that. I would end up using power feed a LOT more often instead of rarely like I (we) do now. Hell, I can't recall the last time I ever used the transverse feed. And the only times I've used the longitudinal feed is where I have to make cuts of over about 4 inches. And sometimes not even that if it's only one pass. The gear noise bothers me that much.

              I would also like to include some way to disengage the tail end drive for times when we did want a direct feed. I don't think it would be often but it would be nice to keep the option open.
              Chilliwack BC, Canada

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              • #37
                I think I will take your method and apply it to my Bridgeport for the X axis.

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                • #38
                  Originally posted by J Tiers View Post
                  If they thought so, why do YOU insist that it is BETTER NOT TO KNOW the rate? You evidently need to go to some graveyards and tell those folks how stupid they were!
                  Who said that? not me.

                  The reality is MOST power feeds do not convey the rate at all, and stuff still gets made.
                  Last edited by lakeside53; 04-16-2018, 09:01 PM.

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                  • #39
                    Originally posted by JCByrd24 View Post
                    . . .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.
                    OK, yeah, I was thinking about post #8 which suggested exactly that. I'd do that in a heartbeat.
                    Southwest Utah

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                    • #40
                      If you do that it's best integrated with some form of motor braking. Easy to do.

                      I had exactly that on my prior lathe which has a separate electromagnetic brake. Not only did it work well, it saved my ass a few times With care makes for really nice threading stops very close to a shoulder, closer that you can get without significant pucker.

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                      • #41
                        Originally posted by lakeside53 View Post
                        Who said that? not me.

                        The reality is MOST power feeds do not convey the rate at all, and stuff still gets made.
                        Sigh.......

                        No doubt that is so, no doubt that is so.... Your opinion is, of course, not binding on the rest of us. I find it reasonably good to have some general clue about the feed, which in my case is easy enough with a clock and a crank at 0.1" per rev, whenever I consider it appropriate.

                        If I provide myself with a power feed, I trust it will not excessively discommode you if I also provide myself a table of approximate feeds corresponding to various settings. I admit I will lose no sleep over any internal discomfort that table may cause you or others, however.

                        I had mentioned, as examples, that many manufacturers of serious industrial mills, for instance, provided built-in feeds of known and settable rates.... and that the feed rate in IPM at different settings is commonly listed in a table for lathes as well, to assist in deciding what rate will be good with the tool you are using.

                        You may feel free to ignore those, it is your right. You may cover those heathen idols up, or even go and rant at the graves of the designers who foolishly thought that providing tables of feed rate was useful.
                        Last edited by J Tiers; 04-16-2018, 10:21 PM.
                        CNC machines only go through the motions

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                        • #42
                          hey, you said "It ain;t worth wasting the electrons to argue over it....."

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                          • #43
                            Originally posted by lakeside53 View Post
                            hey, you said "It ain;t worth wasting the electrons to argue over it....."
                            I can be as inconsistent as the next person...... and I even enjoy it. I am descended from three ethnicities that either like to argue, or are stubborn..... I've listed them before so I need not repeat them.
                            Last edited by J Tiers; 04-18-2018, 09:22 PM.
                            CNC machines only go through the motions

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                            • #44
                              Originally posted by J Tiers View Post
                              ... I am descended from three ethnicities that either like to argue, or are stubborn.....
                              And have the incessant need to always get in the last word.
                              Location: Long Island, N.Y.

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                              • #45
                                Originally posted by J Tiers View Post
                                I can be as inconsistent as the next person...... and I even enjoy it. I am descended from three ethnicities that either like to argue, or are stubborn.....
                                Ok, that's two; What's the third?

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