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  1. #1
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    Default Worm Gear - Looking for a used one

    I am looking for a used worm gear, around 22 to 25mm in diameter with about the 30o rake. Something like this. I just need the worm and will make the gear to suit. It needs to be a coarse pitch as shown in the picture.

    Click image for larger version. 

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  2. #2
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    Default Re: Worm Gear - Looking for a used one

    See if you can get a drive gear from a gate motor. Centurion make a solid for sliding gate motors.

  3. #3
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    Default Re: Worm Gear - Looking for a used one

    How are you going to make the gear to suit?

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    Default Re: Worm Gear - Looking for a used one

    I will probably end up hand cutting and filing both. Modern gearboxes worm gears have a pitch that is a little too fine.

  5. #5
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    Default Re: Worm Gear - Looking for a used one

    I dont know what you are making but its easier to machine the worm and use it to make the gear.

  6. #6
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    Default Re: Worm Gear - Looking for a used one

    I am recreating an antique device. These things were made by hand so I am sure I can make a set. I am unsure if a lathe can cut such a coarse thread. The finer it is and it will not wind back. It simply is some elbow grease and I am reasonably handy with hand tools. I am thinking also of spiral winding a coil from 3mm rod and this will become the worm.

  7. #7
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    Default Re: Worm Gear - Looking for a used one

    https://croftsgears.co.za/

    Not used, but much easier!

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  8. #8
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    Default Re: Worm Gear - Looking for a used one

    Ive made a worm and wheel on my lathe and it was a 6mm dp thread. Quite course. I made the worm longer than necessary and used the worm as a hob to generate the wheel. I basically made a cutter from the worm and hardened it to cut a brass gear. It came out real sweet .The teeth on that clock gear ? do not have a normal profile of a gear so it may be very different process.
    Clickspring has nice videos of filing tooth profiles for clock gears etc.

  9. #9
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    Default Re: Worm Gear - Looking for a used one

    Ja, familiar with how to make fine pitches, you can even use a tap to do the brass gear if you want standard pitch sizes.

    Will check Clickspring out thanks.

  10. #10
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    Default Re: Worm Gear - Looking for a used one

    Difficult to see scale in the photo. What is the pitch of the worm?
    Beat-up rat rod of a '96 Nissan Patrol that bears the evidence of many wonderful adventures (and a few stupid indiscretions).

  11. #11
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    Default Re: Worm Gear - Looking for a used one

    Difficult to tell but I would gauge ot between 22 and 25mm diameter. Roughly counting the teeth looks like a 15:1 ratio.

    The worm drives the speed governor. This is what I am busy making.


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  13. #12
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    Default Re: Worm Gear - Looking for a used one

    Scaling from the original photo, if the worm is 22-25mm OD (assuming you meant OD and not pitch or effective diameter), and assuming the worm is single-start, then the pitch is between 8 and 9.2mm. I believe that is outside the range of most manual lathes. Certainly it's outside the range of my lathe.

    It could be done on a CNC lathe. But setting up and doing one off on a CNC might be more than you want to pay.

    I know a guy who can, if you want I can PM you his contact details.
    Last edited by Peter Connan; 2021/04/30 at 07:50 AM.
    Beat-up rat rod of a '96 Nissan Patrol that bears the evidence of many wonderful adventures (and a few stupid indiscretions).

  14. #13
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    Default Re: Worm Gear - Looking for a used one

    Get it 3d printed in a suitably tough material
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  16. #14
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    Default Re: Worm Gear - Looking for a used one

    Thanks guys, I want to try make is look as original as possible. It is a single start so should not be too difficult, hell I've ground a telescope mirror to within a couple of wavelengths of light, I am sure I will manage .

  17. #15
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    Default Re: Worm Gear - Looking for a used one

    I'm not sure of the size, but the Peugeot 404 uses a worm drive in the diff.
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  18. #16
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    Default Re: Worm Gear - Looking for a used one

    To close the thread out.

    Found an elegant solution, the guys in the screw conveyor industry use it.

    Simply put it is a series of washers that are split on one side and then stretched out to the correct pitch and then each washer is welded together to for a long spiral which is then placed on the shaft. Will work perfectly for me.



    There is a spreadsheet that the guy posted to assist you in determining the washer size.

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