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

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  • #16
    Here's the arrangement set up on my HLV. As you can see the pair of 22's won't mesh unless you make a new hub (which is a simple enough job). Of course, if you got any other gears with your machine in addition to the five standard ones, you could put in a bigger idler than the 22T then it would fit just fine.

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    (Another option would have been to move the 60 in and the 55 out then flip the 22/30 and put the 22 idler between the 30T and 60T. Sadly that won't work because the 22 will never come close enough to the 60T to mesh with it.)

    Yet another option with the standard gears would be to flip the 22T idler over and put a smaller diameter washer behind it as a spacer. Then it would mesh but the large head of the retainer would foul the 30T so you would have to kludge up a bolt and spacer like in the pic below. If you can do this, you'll get 8tpi threading with the dial set to position 1.

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    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

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    • #17
      If you can double the lead screw speed and select 16 tpi it would work.
      The Smart & Brown model A only goes to 8 tpi, so to get 6 and 5 tpi, I doubled the gearing and selected 12 and 10 tpi respectivly. I did replace the safety link temporarily, for fear of it breaking with the extra stresses and was extra careful not to loose concentration and have a pile up.

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      • #18
        Peter., that certainly looks like a good way to go.
        Southwest Utah

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        • #19
          Originally posted by chipmaker4130 View Post
          Peter., that certainly looks like a good way to go.
          Well, it works on my HLV, hopefully Sid's clone is set up similar and he has the right gears. It would be interesting to find out what DP gears his machine uses.

          Originally posted by old mart View Post
          If you can double the lead screw speed and select 16 tpi it would work.
          The Smart & Brown model A only goes to 8 tpi, so to get 6 and 5 tpi, I doubled the gearing and selected 12 and 10 tpi respectivly. I did replace the safety link temporarily, for fear of it breaking with the extra stresses and was extra careful not to loose concentration and have a pile up.
          That would work on most mchines but not on the Hardinge Mart. The gearbox is entirely internal for all the pitches on the chart so you cannot alter them in any way. For any other pitch you have to disconnect the gearbox and use the end gears. There is no way to combine the two, in fact there's an interlock to prevent it.
          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

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          • #20
            Well guys, thanks for the help, but what I really need after looking at my cad file again is .25 pitch! Not .125!

            Sid

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            • #21
              I didn't know the Hardinge lathes wouldn't do 8tpi. But not surprising. My first CNC lathe with a 5hp spindle struggled with 1"-8tpi in mild steel. The final tool passes have quite a large tool contact so any lack of rigidity can cause a catch breaking the tool or worse. There are roundabouts for a CNC, like two threading cycles each doing half the depth, but the manual machine still needs the 8 tpi gearing. Where ever possible we milled coarse threads.

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              • #22
                Originally posted by sid pileski View Post
                Well guys, thanks for the help, but what I really need after looking at my cad file again is .25 pitch! Not .125!

                Sid
                You could achieve that by swapping the 60 and 30 then choosing position 2 on the dial. You'd definitely have to make a new hub for the idler though and you're risk of damaging something would go up a lot. If it's a 2-start thread, not so much.
                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

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                • #23
                  Peter in post #16 refers to making a new hub to allow greater variety of gears to be fitted. I am guessing that his "hub" is the swinging quadrant. A modified one would probably work for the job, but would have to be used with the door open as it woulf hang down a couple of inches more than the standard one. 4 TPI is a big jump from 11tpi and might be unobtainable.

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                  • #24
                    Well, I just had to look at my 10ee, this seems like a decent selection of threads, from 3 TPI to 92. I think I should make this lathe my next big project and actually use this thing...
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                    • #25
                      Though all my lathes will cut a 1/4" pitch thread, I would try to stick to only the 14+ up ones. The HLV-H is very rigid machine for it's size, but cutting 4 tpi might be asking a bit much of it. Doesn't hurt to try I guess. What's the low spindle speed?
                      21" Royersford Excelsior CamelBack Drillpress Restoration
                      1943 Sidney 16x54 Lathe Restoration

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                      • #26
                        Originally posted by The Metal Butcher View Post
                        Though all my lathes will cut a 1/4" pitch thread, I would try to stick to only the 14+ up ones. The HLV-H is very rigid machine for it's size, but cutting 4 tpi might be asking a bit much of it. Doesn't hurt to try I guess. What's the low spindle speed?
                        It has a VFD, so can go really slow.

                        Sid

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