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  1. #1
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    Default Hercus Leadscrew Handwheel

    I am considering putting a handwheel on the tailstock end of the leadscrew - like Myford Super 7's have, but not much of the leadscrew protrudes from the bearing, and it is 1/2" in diameter.

    First thought is to remove the leadscrew, and drill and ream it to take an extension shaft then thread and glue /transverse pin / grub screw / weld the extension into the leadscrew.

    Alternatively, move the bearing towards the headstock to give / expose the end of the leadscrew so the handwheel can be mounted onto it. To do this, re-using the mounting screw hole in the bed - closest to the headstock, and drilling a new leadscrew bearing mounting hole in the bed closer to the headstock. This would limit the carriage movement a little more than one inch. It would mean machining some of the leadscrew thread off to accommodate the bearings move towards the headstock.

    I can't find anything on the web for South Bend or Hercus lathes, and I can't believe that no-one has done this before.

    All suggestions are most welcome.

  2. #2
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    Default

    Curious, why would this be a useful addition. I don't have one on any of my lathes, so I have no experience of using one.

    Sent from my SM-N976B using Tapatalk

  3. #3
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    Default

    Quote Originally Posted by A J in WA View Post
    I can't find anything on the web for South Bend or Hercus lathes, and I can't believe that no-one has done this before.
    I suspect it just isn't worth the effort. I honestly can't think of a use for such a feature. What did you have in mind for it AJ?
    Chris

  4. #4
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    I use the handwheel on the Myford to measure precise distances along the job. As an example I was making some facsimile cleaning rods for the Japanese Type 38 Arisaka. There is a groove and a step at the end. This is easy to do with the handwheel. If I was making lots, I would set up the six station carriage stop, but it takes ages to set up.
    Arisaka Type 38 Cleaning Rod.jpg
    Last edited by A J in WA; 2nd Aug 2020 at 02:58 PM. Reason: Photograph added.

  5. #5
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    Default

    Hi AJ, Guys,

    Quote Originally Posted by A J in WA View Post
    I use the handwheel on the Myford to measure precise distances along the job. As an example I was making some facsimile cleaning rods for the Japanese Type 38 Arisaka. There is a groove and a step at the end. This is easy to do with the handwheel. If I was making lots, I would set up the six station carriage stop, but it takes ages to set up.
    Arisaka Type 38 Cleaning Rod.jpg
    I completely agree with you, the calibrated hand wheel makes turning precise amounts easy.
    I've recently made some bearing spacers that have to be an exact length. Knowing exactly how much I must remove to get the right length is simply a matter of dialling the amount needed on the leadscrew hand wheel.
    Its all about technique !
    Best Regards:
    Baron J.

  6. #6
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    Default

    Ok, thanks for the explanation. Makes sense. I am a bit spoilt, I've got a DRO on that axis.....but not on my 2 Hercus 9's....had to rely on carriage stops and/or sneaking up on the cut and measuring along the way.
    Be interesting to see how you go with this modification. Cheers.

    Sent from my SM-N976B using Tapatalk

  7. #7
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    Quote Originally Posted by Silversprings View Post
    Ok, thanks for the explanation. Makes sense. I am a bit spoilt, I've got a DRO on that axis.....but not on my 2 Hercus 9's....had to rely on carriage stops and/or sneaking up on the cut and measuring along the way.
    Be interesting to see how you go with this modification. Cheers.

    Sent from my SM-N976B using Tapatalk
    Hi Silversprings,

    If you think about it the leadscrew is just a long accurately made thread so each turn will move the saddle an exact distance. The hard bit is a calibrated wheel on the end so you can determine exactly how far the saddle will move for what ever fraction of a turn. Obviously you do have to take up any backlash in the direction that you want to go !

    You can easily get within a fraction of a thou this way.
    Best Regards:
    Baron J.

  8. #8
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    Default

    I just use a magnetically held dial indicator on my ways set to a predetermined zero as my stop. Run the carriage almost up to the zero disengage the half nuts and take the cut of the thou needed to the zero.

    I can do it reasonably well and accurately now.

  9. #9
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    Default

    Quote Originally Posted by A J in WA View Post
    I am considering putting a handwheel on the tailstock end of the leadscrew - like Myford Super 7's have, but not much of the leadscrew protrudes from the bearing, and it is 1/2" in diameter.

    First thought is to remove the leadscrew, and drill and ream it to take an extension shaft then thread and glue /transverse pin / grub screw / weld the extension into the leadscrew.

    All suggestions are most welcome.
    Hi AJ, I've just been rereading this thread and thinking about what you said ! I agree a shaft extension is probably the better way to go. At least you wont have to mess about with the support bearing for the end of the leadscrew. A welded or pinned joint isn't going to slip either. The only issue is a calibrated wheel handle. This website can produce a calibration tape if you can give it the right parameters.

    https://www.cgtk.co.uk/metalwork/calculators/divider

    There are other calculators on that site as well that could be useful.

    HTH.
    Best Regards:
    Baron J.

  10. #10
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    Default

    Could you make the handwheel with an internal thread to replace the nut? You could probably remove the thick washer to gain some extra shaft length. High strength Loctite might be enough to secure it.
    Attached Images Attached Images
    Chris

  11. #11
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    Quote Originally Posted by jack620 View Post
    Could you make the handwheel with an internal thread to replace the nut? You could probably remove the thick washer to gain some extra shaft length. High strength Loctite might be enough to secure it.
    Hi Guys,

    Hey Chris, that is a good Idea ! Make a special nut to replace the original one that extends the leadscrew enough to get a calibrated handwheel onto.

    I do believe that ARC Euro have suitable handwheels in stock as well

    https://www.arceurotrade.co.uk/Catal...heels---Chrome

    Only 65 mm diameter, may not be big enough, just under a 5 UK.
    Best Regards:
    Baron J.

  12. #12
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    Mar 2013
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    Mt Pleasant SA
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    Default

    Another way to lock the handwheel if using a female thread in it, provided the handwheel hub is deep enough, would be to use a counter-screw i.e. a male version of a locknut.

  13. #13
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    Just realised that my lead screw bearing block is different than yours. Mine is the classic 9" version. This would present a different set of challenges to extend for a hand wheel. Anyway, I then thought, why not make a graduated ring around the saddle hand wheel. A lot of modern lathes have these. I think this would achieve your goal of accurate measurement along the bed axis. And would be an easier modification to achieve (I reckon, without giving it a lot of thought...yet). Cheers, Tony

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  14. #14
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    Default

    Thanks everyone for the suggestions. It is most appreciated.

    Here is another thought I would like some opinions on.

    It is: remove the tailstock end bearing, and machine about half an inch or so off it! This would give a bit of the leadscrew to attach a handwheel to. I don't think the remaining bearing would be too weak to support the leadscrew. I think it is "over engineered" for the job. I think the size that it is, is to facilitate ease of manufacturing.

    The forces on the leadscrew when feeding towards the headstock would be taken by the tailstock end bearing. In reverse, feeding towards the tailstock would apply force to the headstock end bearing...... I think, or is it vice-versa?

    The added advantage of my "cunning plan" is that if the bearing fails, I can easily obtain another, and there is no machining on the leadscrew or bed left behind after the bearing has been replaced - to show that my cunning plan failed!

  15. #15
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    Hi AJ,

    I wouldn't try machining the leadscrew support bracket. I would be more inclined to go with drilling and threading the end of the leadscrew to fit a short extension piece. The lathe remains original and if done properly it can be easily returned to original. Plus I think that you may run into the overhang on the lathe bed with the wheel.

    Tony: There is a design for a precision saddle hand wheel that is calibrated in thou's. Simply using the existing saddle hand wheel won't give you accurate movement to the thou. Pop a dial gauge in the tailstock chuck and try it, it will be almost impossible to get to the thou repeatedly. The Myford S7LB leadscrew hand wheel is already calibrated in thou's and can easily be read to a 1/4 thou.
    Best Regards:
    Baron J.

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