Announcement

Collapse
No announcement yet.

Some heavy work with the Lewis mill, hogging out the forming die.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Some heavy work with the Lewis mill, hogging out the forming die.

    Started work on the forming die for EMT ends. I decided that since I did not have large diameter end mills for the angle cut some suggested, I would instead cut the form using a convex cutter on the horizontal mill.

    The setup



    In the cut, first pass (I did not think I wanted to do it all in one pass, but I may have been wrong)



    In the cut, second (final) pass, full depth possible with the standard spacers.



    The cutter and work after final pass. The cutter is not large enough diameter to cut full depth without rubbing the standard spacers on the 1" arbor. Yoiu can see rub marks on the first wider spacer on the left... I had to ease it up about 20 thou from where I wanted it.



    I might have been better off to do the cut in one deep pass, the cutter slammed a LOT less on the second cut as it started, and the mill seemed OK with it once there were a couple teeth in the cut. But, we got through it.

    The cutter could also have been sharper.... but I do not have an indexing arrangement for what passes as a T&C grinder here. Looks like I have at least two more tooling projects for the T&C... If it is a nice cold winter, I may get something done in the shop.

    The overarm supports are essential for this sort of cut on a small mill, otherwise everything will be deflecting in different directions. I need to move the support screw down, the overarm was letting the arbor spring slightly on the start of the cut, which I did not like. Not sure how I will handle that, I do not want to drill and tap the relatively thin support casting.
    Last edited by J Tiers; 08-24-2020, 03:55 PM.
    1601 2137 5683 1002 1437

    Keep eye on ball.
    Hashim Khan

    If you look closely at a digital signal, you find out it is really analog......

  • #2
    Jerry,
    Art Voltz would be proud of you !.
    Art introduced me to his Lewis mill back in 2000.
    It was the same mill that was used/ discussed in Popular Mechanics in the 1960's and was Art's pride and joy
    He was a member of the Houston Metal Workers Club and passed away back in 2003
    Don't know what happened to the Lewis and assume a club member got it.
    Nice cut by the way !
    Rich
    Green Bay, WI

    Comment


    • #3
      Never met Art, Swapped some tooling etc with him by mail, got some drawings etc from him, but never met in person. Super good guy, we all miss him.

      That cut would have gone easier and been cleaner if I had means to sharpen properly. I stoned the faces, but it was not "stupid sharp" as it should be.
      Last edited by J Tiers; 08-24-2020, 04:33 PM.
      1601 2137 5683 1002 1437

      Keep eye on ball.
      Hashim Khan

      If you look closely at a digital signal, you find out it is really analog......

      Comment


      • #4
        Originally posted by J Tiers View Post
        Started work on the forming die for EMT ends. I decided that since I did not have large diameter end mills for the angle cut some suggested, I would instead cut the form using a convex cutter on the horizontal mill.

        The setup



        In the cut, first pass (I did not think I wanted to do it all in one pass, but I may have been wrong)



        In the cut, second (final) pass, full depth possible with the standard spacers.



        The cutter and work after final pass. The cutter is not large enough diameter to cut full depth without rubbing the standard spacers on the 1" arbor. Yoiu can see rub marks on the first wider spacer on the left... I had to ease it up about 20 thou from where I wanted it.



        I might have been better off to do the cut in one deep pass, the cutter slammed a LOT less on the second cut as it started, and the mill seemed OK with it once there were a couple teeth in the cut. But, we got through it.

        The cutter could also have been sharper.... but I do not have an indexing arrangement for what passes as a T&C grinder here. Looks like I have at least two more tooling projects for the T&C... If it is a nice cold winter, I may get something done in the shop.

        The overarm supports are essential for this sort of cut on a small mill, otherwise everything will be deflecting in different directions. I need to move the support screw down, the overarm was letting the arbor spring slightly on the start of the cut, which I did not like. Not sure how I will handle that, I do not want to drill and tap the relatively thin support casting.
        that's some good hog out, nice work

        Comment


        • #5
          Amazing how it can in one pass if you chose too.A horizontal mill looks very usefull.What is it making. EMT?

          Comment


          • #6
            Once 2 teeth are cutting it starts to smooth out... usually..
            Last edited by 754; 08-25-2020, 01:59 AM.

            Comment


            • #7
              The work is a die to flatten the ends of EMT for making structural members for light work. Yes, very good to have a horizontal mill, it does things that vertical mills have trouble with. In this case, as the mill is a light one (table is about 4" wide), I could not just throw it in power feed and let it rip. I had to "baby" it a bit. Also there is no power feed (yet).

              The key is feed, the depth of cut is important, but sets torque requirements, etc, not so much the SFM etc. I put it in back gear, with cutter going at about 40 rpm or so. Bigger depth of cut keeps more teeth on the cut, and stabilizes everything.

              As the cut starts, the highest tooth starts slamming into the work. The more "end-on" it hits, the worse. That tends to bounce around the table, and looks scary. It is also probably bad for everything, loosens clamping, stresses everything, including nerves.

              So a deeper cut makes the first contact more of an upward and forward cut, with less direct impact. The downside is that the deeper the initial cut, the more the forces of cutting tend to raise the work. That loosens clamps especially if you have a bit of a shaky setup, like the one I show above, with clamps on one side only. But, with one t-slot, you are stuck.

              No way on a machine like this can you take a climb cut unless it is very very light. The highest tooth will tend to pull the work the most, and if you increase the depth of cut, then things get worse with the cutter pulling through the backlash and ending up "walking over" the work, bending things and scarring up the work.. There always is a "highest tooth", nothing , especially milling arbors is ever perfect. But once the cutter gets into the work with at least two in at all times, the action will indeed smooth out a great deal in general.
              Last edited by J Tiers; 08-24-2020, 10:30 PM. Reason: clarification "flatten the ends of EMT"
              1601 2137 5683 1002 1437

              Keep eye on ball.
              Hashim Khan

              If you look closely at a digital signal, you find out it is really analog......

              Comment


              • #8
                You mentioned you did not any way to index the tool for grinding. Using a spring finger against the back of the tooth is a common way to index the cutter. On the first sharpening it is best to grind the back of the tooth with the finger bearing on the face of the tooth. That eliminates the possibility that the teeth are not of uniform thickness. That only needs to be done at the first sharpening.

                Comment


                • #9
                  Well, I don't know that the cutter is done right as it is now. In fact, I have some reason to suspect not, since there are a couple or three teeth that cut way earlier than the others, and it was a good fit on the arbor, so less likely that it was way "out" as-mounted. Plus, the "high" ones do not seem to vary in "height" as they would if a true circle was off-center.

                  If the spacing is not exactly consistent, then some edges will be at a different "height", because of the back relief. Since I don't know that they are consistent now, I really need to do the indexing to begin with. After that, I maybe can do as you suggest.

                  I need to do a quick indexer anyway, since I have a backlog of cutters that need a real sharpening. I need a good T&C, the one I have has a makeshift head on it, and needs scraped-in.
                  1601 2137 5683 1002 1437

                  Keep eye on ball.
                  Hashim Khan

                  If you look closely at a digital signal, you find out it is really analog......

                  Comment


                  • #10
                    Did you run this cut dry, Jerry? If so, Why? I have a Sheldon Horiz, and usually slobber on something like rapid-tap for jobs like this.
                    I cut it off twice; it's still too short
                    Oregon, USA

                    Comment


                    • #11
                      I did, and usually do, unless it is obvious that the cutter is in distress. I find that with milling, a little oil leads to a lot of "carry-around" of chips, with re-cutting and so forth. The chips were clearing, dropping in a pile in front, and behind the cutter, which was fine.

                      As far as I can see, with cutting oil etc, a little is not as good as a lot. A little acts as an adhesive for chips, a lot floods the cut and carries the chips away. Since I am not set up to handle a lot of cutting fluid/coolant, I use none if I can get away with it, as I did here.

                      I sometimes will use an air blast on the mill, which clears the chips, but unfortunately tends to clear them all over everything around, including me. Mist systems seem to be not enough air to move chips, but plenty enough coolant to stick them to the cutter just where they are not wanted.
                      1601 2137 5683 1002 1437

                      Keep eye on ball.
                      Hashim Khan

                      If you look closely at a digital signal, you find out it is really analog......

                      Comment


                      • #12
                        Tiers when I first looked at that Cutter reminded of a River Boat Paddle Wheeler lol! Nice Work!

                        Comment


                        • #13
                          Originally posted by Rich Carlstedt View Post
                          Jerry,
                          Art Voltz would be proud of you !.
                          Art introduced me to his Lewis mill back in 2000.
                          It was the same mill that was used/ discussed in Popular Mechanics in the 1960's and was Art's pride and joy
                          He was a member of the Houston Metal Workers Club and passed away back in 2003
                          Don't know what happened to the Lewis and assume a club member got it.
                          Nice cut by the way !
                          Rich
                          Any idea how many casting kits were sold?
                          From the information on VintageMachinery, other machines were available as well: http://vintagemachinery.org/mfgindex...l.aspx?id=1854

                          Comment


                          • #14
                            There may be no information on how many of each type machine were sold. I have never found any, but Art Volz did mention that he had more information, which, unfortunately, he did not distribute as far as I know.

                            The Vintage Machinery info suggests Lewis Machinery lasted from 1935 through at least 1957, which suggests that they may have made quite a few machines. I know several people here have examples, and one person either here or on PM has Art Volz's mill, which is the one owned by Walter Burton, who wrote the article for Popular Science.

                            Back in those days Popular Science was a hands-on magazine to some extent. I recall a series on building a ship model driven by a steam turbine, for which plans were included, if you can credit that. That article was in the early 1960s. The model was of the Savannah, which was a prototype nuclear powered merchant ship ( https://en.wikipedia.org/wiki/NS_Savannah )

                            The mill article mentioned was actually from 1948, detailing modifications to the mill kit, although not including the back gears, which I regard as one of the best of them in terms of how useful and essential it is.
                            1601 2137 5683 1002 1437

                            Keep eye on ball.
                            Hashim Khan

                            If you look closely at a digital signal, you find out it is really analog......

                            Comment


                            • #15
                              I want to see some updates on the die itself. How's that progressing? Is there another thread that I missed?

                              Comment

                              Working...
                              X