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Will a Longworth chuck mounted outboard with reversed rotation work?

Discussion in 'Getting Started' started by Greg Muller, Jun 27, 2020.

  1. Greg Muller

    Greg Muller

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    Or do I need a different Longworth?

    I'm getting ready to order a Longworth chuck, but it occurred to me that I've never used one, or seen one used when the spindle is rotating clockwise, which is outboard direction on my lathe.

    Do I need another for that use, or do they lock somehow?

    Thanks.

    EDIT: Found my answer. Sorry for the inconvenience. Mods can delete the thread.
     
    Last edited: Jun 27, 2020
  2. hockenbery

    hockenbery AAW Advisor Staff Member

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    In case someone else has the same question.

    No. The longworth chuck opens and closes much like the aperture on a camera lens.
    once closed and locked it should stay locked.
    Whether the piece stays in chuck depend on how well it is gripped And the forces applied to the piece by speed or turning,
     
  3. Arkriver

    Arkriver

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    Others may disagree, but in my opinion a longworth chuck without tail stock support is an accident waiting to happen.
     
  4. hockenbery

    hockenbery AAW Advisor Staff Member

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    No disagreement here.
    Cole jaws and longworth chucks both derive their holding power from the geometry of the rim and buttons used to hold the rim.

    I much prefer a jamb chuck but it doesn’t allow turning in the very center of the bottom.
     
  5. Robert D Evans

    Robert D Evans

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    A donut chuck is my preferred way to finish the bottom of bowls. Much safer than a Longworth chuck or cole jaws. The bowl is completely captured. It's just a little time consuming to set it up and of course you have to have the proper sized donut to hold the bowl. It's a lot cheaper too. For the price of a sheet of MDF, a few bolts and a face plate, you are in business.
     
  6. Greg Muller

    Greg Muller

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    Have you seen Ron Brown's combo version 2? Longworth and donut chuck combined. Sure looks like it'd be easier to center that way.
     
  7. Mark Jundanian

    Mark Jundanian

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    Yes. I have the Ron Brown Longworth with the donut attachement. It is solidly built and works well. Set up doesn't take too long, including centering. My pieces have no place to position the tail stock, so I start with the donut for the gross re-fashioning of the bottom, then do the final shaping and sanding with just the Longworth. I have never lost a piece, but at that point I am using a very light touch.

    Ron's Longworth 2 model threads on to the spindle which is a much better design than the original version that Rockler sells, which has to mount in chuck jaws (and incidentally will not fit Nova jaws).

    Another note about the Cole jaws from Nova, which might be the most common ones out there. The Nova jaws are sold with a set of grey buttons and these buttons do not hold well at all. The elastic material is too smooth and the buttons are cylinder shaped such that when tightened down they bow out in the center like a barrel, which tends to push the piece off the chuck.

    Nova sells an accessory set of buttons which is well worth buying. These are black and offer two shapes that are both effective and offer a variety of hold options. Since switching to the black buttons I have had no failures of hold with the Cole jaws, which I will sometimes use instead of the Longworth.
     
  8. GRJensen

    GRJensen

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  9. Greg Muller

    Greg Muller

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    Ron Browns combo unit is really intriguing to me. I may jump on it. If so, I'll want the version that clamps into chuck jaws, as I have a couple lathes and my inboard/outboard has different threads, too. I have adapters, though, so i guess it wouldn't make too much of a difference.
     
  10. Mark Jundanian

    Mark Jundanian

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    Ron's original fitting requires that your 50 mm chuck jaws have a dovetail on the inside, i.e. the jaws are designed grab a dovetailed tenon. The 50 mm Nova jaws are dovetail on the outside, but not the inside. I know there are jaws out there that work, but I suggest speaking directly with Ron about the suitability of the jaws you plan to use.
     
  11. Mark Jundanian

    Mark Jundanian

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    The observation I make is that although the buttons are tall, they are straight sided. I prefer buttons that are fatter away from the jaws than they are close to the jaws. I believe these have tendency to hold better, all other factors being equal.
     
  12. Greg Muller

    Greg Muller

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    I have the Vicmarc 120 with standard jaws. They are dovetailed inside and out, 10°.
     
  13. Greg Muller

    Greg Muller

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    Regarding those tall grippers, I emailed the site owner about using them on a Longworth.
    His response:

    "Thank you for your interest. No, these will not work on your Longworth style chuck. The Longworth chuck uses grippers that are tapered inward towards the top. They have to remain a bit loose until the chuck is rotated to advance the grippers towards the piece you're holding. Then, as you apply the final tightening they will tip in one final bit to apply pressure. My grippers will not act that way and so will not apply enough pressure to hold the piece. It would be dangerous. The covering on my grippers is harder than the Longworth grippers and are intended to be used on scroll type chucks that can apply the pressure required to securely hold your work.
    Regards,
    Dennis"
     

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