Using a rotary table

Advert

Using a rotary table

Home Forums Help and Assistance! (Offered or Wanted) Using a rotary table

Viewing 13 posts - 1 through 13 (of 13 total)
  • Author
    Posts
  • #583690
    david gregg 1
    Participant
      @davidgregg1

      I have a rotary table with a 90 To 1 reduction and also 4 division plates which cover a wide range of holes can any body tell how to work out the number of holes to use so that I can divide this into 100 so that I can scribe that l can scribe the lines I know that I need to turn 3.6 degrees so less than a full turn of the handle

      Advert
      #33961
      david gregg 1
      Participant
        @davidgregg1

        I want to put calibration marks on a indexing dial

        #583694
        Emgee
        Participant
          @emgee

          David

          Please advise the number of holes per circle in the plates, the plate to use can then be calculated.

          Emgee

          #583698
          Hopper
          Participant
            @hopper

            YOu need to get a copy of the Workshop Practice Series book Dividing. All is revealed in there.

            Including that 100 divisions on a 90:1 ratio dividing head can be achieved by moving 18 holes at a time on a circle of 20 holes. Or a multiple thereof, such as 36 holes on a 40 hole circle. Or 72 holes on an 80 hole circle.

            Or you can work it out: 90/100 x number of holes in the circle. Answer of course must  be a whole number as you cant move half a hole etc.

            It gets complicated. Best to get the book. Also there are online spreadsheets and charts. Be wary of the Vertex chart, it contains errors but I forget for which divisions.

            Edited By Hopper on 02/02/2022 23:43:33

            Edited By Hopper on 02/02/2022 23:45:02

            Edited By Hopper on 02/02/2022 23:46:19

            #583699
            noel shelley
            Participant
              @noelshelley55608

              18 holes in a 20 circle, 27 holes on a 30 circle, 36 holes on a 40 circle , 45 holes in a 50 circle, 54 holes in a 60 circle. Etc ! Hole circle divide by 10 then X 9 = holes needed to be moved. Good luck, Noel.

              Edited By noel shelley on 02/02/2022 23:53:01

              #583704
              Thor 🇳🇴
              Participant
                @thor

                Hi David,

                There is an online calculator here, that you may find helpful. As others have mentioned, you need a 20 hole (or multiple thereof) division plate.

                Thor

                #583719
                SillyOldDuffer
                Moderator
                  @sillyoldduffer

                  If the table is one of the HV6 family, Howard Lewis gave us this corrected table. For 100 holes he gives Wheel A, with 20 holes, then 18/20, which agrees with Noel.

                  As many of us find keeping count painful, driving the table with a micro-controlled stepper motor is a popular alternative. The software does all the hard sums, keeps count and there's no need to mount the division wheels. Ask again if that's of interest.

                  Dave

                  #583724
                  not done it yet
                  Participant
                    @notdoneityet
                    Posted by noel shelley on 02/02/2022 23:45:23:

                    18 holes in a 20 circle, 27 holes on a 30 circle, 36 holes on a 40 circle , 45 holes in a 50 circle, 54 holes in a 60 circle. Etc ! Hole circle divide by 10 then X 9 = holes needed to be moved. Good luck, Noel.

                    Edited By noel shelley on 02/02/2022 23:53:01

                    S’easy when you know how! Noel is spot on with any one of his multitude of options, but you are maybe trying to start at the wrong end of the calculation.

                    It does not matter how many times you turn the handle, you just need those extra spaces for that extra 3.6 degrees on top of the multiple of 4 degrees. You would need to turn that same amount 100 times for a full revolution at 3.6 degrees each time.

                    For 3.7 Degrees, you would need 37/40 of a turn. For 3.9 degrees you would need 39/40ths. For those prime numbers (37 and 39) you cannot use a plate with fewer holes than forty.

                    Your 3.6 degrees would be for a 100 tooth gear, or whatever you might be machining, so you need a plate hole number that when multiplied by 90 is divisible by 100. End of problem, really, in this instance. 90/100 = 0.9. Any plate which has a hole at exactly 0.9 of the way round will do.

                    Try it and see. 20 space plate: 20*90/100 = 18. 50 space plate: 50*90/100 = 45

                    This will be how you can calculate any number of spacings required for any integer-number of teeth on a gear, without recourse to tables on the internet (some of which are known to be incorrect).

                    I’ve never relied on (or even used) tables as the calculation (for gear cutting) is sooo eesy!

                    The only difficulty might be for someone to pick which plate circle to use when it is not the same as the actual number of increments you want per revolution. Plates are (unsurprisingly) made for prime number (or multiples of primes) calculations. Seems complex at first but is simplicity, if not easily befuddled by maths.

                    Think simply – each plate circle is that number as a fraction of 40 (rotary tables with different turns/revolution use the same plates but just different fraction denominators).

                    #583764
                    david gregg 1
                    Participant
                      @davidgregg1

                      Thanks to all those who replied and explained what to do ,I have a plate with 40 holes so I now know that I can move to the 36 hole and go from there and hopefully will remember what to do for any future holes required so thanks to all The forum is such a great source of knowledge

                      david gregg

                      #583784
                      noel shelley
                      Participant
                        @noelshelley55608

                        If your using dividing plates then remember to set and use the sector arms ! It will make the job easy. Good Luck Noel.

                        #583791
                        Brian Wood
                        Participant
                          @brianwood45127

                          David,

                          Another useful "tool" is to include a cocktail stick so that you have a marker on the last hole from which to index a further 36.

                          Brian

                          #583806
                          Nick Hughes
                          Participant
                            @nickhughes97026

                            Grizzly have quite a good manual for their rotary tables, that explains the indexing method quite well:- Grizzly Manual

                            #583809
                            Dalboy
                            Participant
                              @dalboy

                              Maybe of a little HELP

                            Viewing 13 posts - 1 through 13 (of 13 total)
                            • Please log in to reply to this topic. Registering is free and easy using the links on the menu at the top of this page.

                            Advert

                            Latest Replies

                            Viewing 25 topics - 1 through 25 (of 25 total)
                            Viewing 25 topics - 1 through 25 (of 25 total)

                            View full reply list.

                            Advert

                            Newsletter Sign-up