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Cutting an 8 pitch thread on a hardinge hlvh- help needed

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  • Cutting an 8 pitch thread on a hardinge hlvh- help needed

    i need to cut an 8 pitch worm gear for my clock.
    My HLVH clone only goes as low as 11 pitch.
    I've heard tell that via some trickery, you can cut an 8 pitch thread.
    Anyone here actually done it on an HVLH??

    If so, please enlighten me!

    Thanks, Sid

  • #2
    You need the build the ratio with the change gears.
    Just a note, the change gears only compound through the knob that sets the 1-2-4 multipliers
    but the change gears do not compound through the norton side of the box.

    -D
    DZER

    Comment


    • #3
      As I understand it, the lead screw itself is 8 tpi.
      I need to understand what the change gears need to be at what positions??

      I don't have my set of Hardinge manuals here (home), so I was just looking to see if anyone has actually done it could walk me through the correct combination.

      Thanks, Sid

      Comment


      • #4
        I you want 8 and the leadscrew is 8, just make the drive and the driven gear the same (1:1), and the idler doesen't matter.
        DZER

        Comment


        • #5
          The HLVH lathe he has appears to have a quick change gear box.

          http://www.lathes.co.uk/hardinge/

          So just making the change gears a 1::1 ratio will not do it. I believe this thread describes how to do this:

          https://www.practicalmachinist.com/v...-hlv-h-117764/



          Originally posted by Doozer View Post
          I you want 8 and the leadscrew is 8, just make the drive and the driven gear the same (1:1), and the idler doesen't matter.
          Paul A.
          SE Texas

          And if you look REAL close at an analog signal,
          You will find that it has discrete steps.

          Comment


          • #6
            Thanks guys. More research to be done.
            Not sure what gears I have Wonder if I could just use a timing belt. Seems like an expanding project!
            I think I’ll see what our lathe in our R&D lab will cut on Monday.

            Sid

            Comment


            • #7
              Originally posted by Paul Alciatore View Post
              The HLVH lathe he has appears to have a quick change gear box.

              http://www.lathes.co.uk/hardinge/

              So just making the change gears a 1::1 ratio will not do it.........




              ........................."the change gears do not compound through the norton side of the box." Read what I said.

              --Doozer
              DZER

              Comment


              • #8
                Are you saying that the "norton side of the box" actually means that the quick change gear box is out of the path and you are using manual change gears ONLY with a straight, 1::1 path between them and the lead screw?

                I did read what you said. I do not have this particular lathe so what you said did not register as a way of taking the quick change gear box out of the path. And apparently, from post #3, neither did the OP, Sid Poleski. I also read your post #4 and still it was not clear to me, at least, what had to be done to have this direct setting that by-passes the quick change gear box. I was just trying to point to another discussion where he may get more help. Apparently you do have first hand knowledge of this lathe and quick change gear box. but your description of what to do just did not come across to me. And apparently not to the OP either. I still do not know what "norton" is referring to. I was only trying to help him, not contradict you.

                I know that brevity can be a virtue, but sometimes things need to be spelled out in painful detail.



                Originally posted by Doozer View Post

                ........................."the change gears do not compound through the norton side of the box." Read what I said.

                --Doozer
                Paul A.
                SE Texas

                And if you look REAL close at an analog signal,
                You will find that it has discrete steps.

                Comment


                • #9
                  If the HLV-H is similar to the HLV you'll have to set the gearbox to OUT and configure the end gearing for your pitch. Since the manual only specifies settings for 10TPI and finer threads, you'll have to add a 4/5 multiplier into the train somehow to achieve 8TPI, then go gentle with the cutting loads lest you break something.

                  Here's the relevant pages in case you don't have them:

                  Click image for larger version

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                  Click image for larger version  Name:	hlvh end gears 2.jpg Views:	0 Size:	177.7 KB ID:	1918265
                  Peter - novice home machinist, modern motorcycle enthusiast.

                  Denford Viceroy 280 Synchro (11 x 24)
                  Herbert 0V adapted to R8 by 'Sir John'.
                  Monarch 10EE 1942

                  Comment


                  • #10
                    Added to that, the above link by Paul Alciatore has reference to the change gears being 20DP 20PA and there are further references about them being 22/29DP gears. They might be 22/29 stub gears or they might well be straight 22DP but I don't think any were 20PA because they simply wouldn't fit in standard config. UK models are straight 22DP 20PA end gears.

                    Incidentally, and just for interest, the UK gearbox has different ratios on the HLV than the US version. We have 19,38 and 72 where you have 27, 54 and 108. I guess that is because of BSP threads being 19TPI where you guys have the 27TPI pipe threads.
                    Peter - novice home machinist, modern motorcycle enthusiast.

                    Denford Viceroy 280 Synchro (11 x 24)
                    Herbert 0V adapted to R8 by 'Sir John'.
                    Monarch 10EE 1942

                    Comment


                    • #11
                      I'll be the smart ass here and suggest you drive the leadscrew with a servo or stepper and have an encoder on the spindle. Who says you need to dick around with gears? It can be temporary solution without hurting your Hardinge.

                      Comment


                      • #12
                        Originally posted by RB211 View Post
                        I'll be the smart ass here and suggest you drive the leadscrew with a servo or stepper and have an encoder on the spindle. Who says you need to dick around with gears? It can be temporary solution without hurting your Hardinge.
                        Well, not so smart ass. Paul Babin (maybe others) offer an ELS for this lathe.
                        Dial in whatever pitch you want. Kind of a big investment for the one gear I need!
                        Know this can be done with the proper gears, and I think I understand what Doozer is saying.

                        Sid

                        Comment


                        • #13
                          No change gears were harmed in the writing of this thread.
                          Paul A.
                          SE Texas

                          And if you look REAL close at an analog signal,
                          You will find that it has discrete steps.

                          Comment


                          • #14
                            The gear in the above chart called "First Gear" (what you'd normally call the stud gear) turns at three different rates compared to the spindle, according to the position of the 1,2,3 knob.

                            Knob
                            Position
                            Spindle
                            turns
                            1st Gear
                            turns
                            1 1.25 1
                            2 2.5 1
                            3 5 1
                            So you need the gear train to be the reverse of any of those ratios in order to turn the 8TPI screw at 1:1 with the spindle for 8TPI threading. You can either swap the 30 tooth screw gear for a 24 in the '10tpi' chart above or swap it for a 48 and use No1 on the 1,2,3 knob, if the train will fit.
                            Last edited by Peter.; 12-27-2020, 05:23 AM.
                            Peter - novice home machinist, modern motorcycle enthusiast.

                            Denford Viceroy 280 Synchro (11 x 24)
                            Herbert 0V adapted to R8 by 'Sir John'.
                            Monarch 10EE 1942

                            Comment


                            • #15
                              Ok, so there IS a way to make a 8TPI train but it does require that the two 22 tooth gears work in mesh with each other, The only issue with that is the original hubs are the same OD as the gears themselves so if you slide them up so the hubs are touching the gears don't mesh. You will need to replicate the hubs with smaller diameter flange to allow those 22T gears to mesh AND you'll have to make a new bolt to clamp it up as the head on the original bolt will foul the 30T gear (or you can fudge the hub flange thicknesses to make it clear).

                              Click image for larger version  Name:	HLV-8TPI.jpg Views:	2 Size:	77.5 KB ID:	1918298
                              Last edited by Peter.; 12-27-2020, 07:11 AM.
                              Peter - novice home machinist, modern motorcycle enthusiast.

                              Denford Viceroy 280 Synchro (11 x 24)
                              Herbert 0V adapted to R8 by 'Sir John'.
                              Monarch 10EE 1942

                              Comment

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