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  1. #1
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    Default Goodell Pratt bench grinder

    Team
    I picked up this little grinder however it's missing a left hand half inch nut to hold the grinding stone in place. I went to the local bolt factory and got an imperial half inch left hand nut and it does not fit. I ended up taking the grinder to the factory and they said they don't have one.

    Is anyone familiar the threads that goodell Pratt used? And does anyone know where I can get a left hand nut for the grinder ?

    Cheers

    Stew


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  3. #2
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    Default

    Looks like a left hand thread?
    H.
    Jimcracks for the rich and/or wealthy. (aka GKB '88)

  4. #3
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    Default

    It is

  5. #4
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    Default

    I assume that you've measured the diameter at 1/2 inch? Short of using a thread gauge you can use a ruler and count how many pitches per inch. From that you have something to ask for if you can find somewhere that sells left hand nuts. Or find a machinist, or twist someone's arm here to make one.

    Graham.

  6. #5
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    I'm definitely more of a wood worker than metal worker :/

  7. #6
    themage21 is offline So that's how you change this field...
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    Default

    I'd hazard a guess that the tpi and the even the pitch angle/thread profile might not be a standard imperial thread on that grinder. It's a nothing job for a machinist to make one (or a couple), but convincing one to do it may be your undoing.

    Goodell-Pratt were bought by Millers Falls, which was in turn bought by Ingersoll-Rand and then looks to have been spun off and then taken over by a Chinese company. Given the dive that has occurred in the quality of the tools they make, I'd say that the intellectual property died around the time of the spin-off from Ingersoll. Which kinda kills the opportunity to email them and ask if they still have plans in a dusty cabinet.

    I can't access it from my current internet connection (annoying blocks all over the place), but this may help: Restoring a Goodell-Pratt Hand Grinder - Lone Pine Toolworks

  8. #7
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    Yes, this is a pretty simple job. If Stew draws a blank on a source, I'll volunteer to make one. I'd need to check that I have some hex stock of the right size, and without a complete thread definition (dia. pitch, thread from, required fit) I'd need the shaft to fit the nut to. I'm located in northern Sydney.

    Graham.

  9. #8
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    I've probably got some hex if you haven't.
    H.
    Jimcracks for the rich and/or wealthy. (aka GKB '88)

  10. #9
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    Default

    Impressive looking grinder but I bet it would enjoy eating the odd finger or two!

  11. #10
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    Quote Originally Posted by clear out View Post
    I've probably got some hex if you haven't.
    H.
    clear out, I found some 1 inch hex stock, so we're OK thanks. Stew is mailing the shaft down.

    I think it needs a machined flat spacer to go between the nut and the grinding wheel. Can anyone suggest how this would have looked?

    Graham.

  12. #11
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    Quote Originally Posted by Oldbikerider View Post
    clear out, I found some 1 inch hex stock, so we're OK thanks. Stew is mailing the shaft down.

    I think it needs a machined flat spacer to go between the nut and the grinding wheel. Can anyone suggest how this would have looked?

    Graham.
    Graham,

    Unfortunately the image for the No.115 (which I think this one is) does not show the spacer, but I am guessing it would be similar to this one:



    cheers,

    Camo

  13. #12
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    Just a plain spacer then, same diameter as the wheel flange. Stew, can you measure the diameter of the flange. I'll make the spacer match.

    Graham.

  14. #13
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    Default

    almost looks to me like beaten up Acme thread, possible? it is American.

  15. #14
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    Yes, from the photo it could well be a square thread of some sort. I'll wait for the shaft, measure it up, then grind a tool if I need to.

    Graham.

  16. #15
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    Stew has sent the shaft to me, it arrived today. The thread is a 1/2" 13 tpi V groove thread, so it's 1/2" UNC. I have a thread cutting tool somewhere, just need to dig it out and get the nut turned.

    Graham.

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