Lathe chucks with unknown backplates

  1. dan.taylor.1

    dan.taylor.1 General Tinkererer

    Hi folks,

    I got 2 unknown 3 jaw lathe chucks with backplates. One is an Elliot 5" with as best as I can measure a 1 3/4" x 6tpi thread, there is also a 7 1/4" faceplate with the same thread.

    _20180929_142121.JPG
    _20180929_142023.JPG

    The other is a 4" unbranded bit looks good quality, with a 1" x 12tpi thread. Both only have the jaws that stick out most in the middle (I want to say external jaws?!).

    _20180929_142049.JPG

    I think I may keep the 5" as I've only 4" on either lathe. What are the backplate and faceplate, and the smaller 3 jaw worth?

    Cheers,

    Dan
     
  2. eLuSiVeMiTe

    eLuSiVeMiTe Forum Supporter

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    1 3/4x6 should fit some smart and browns. Would need to check later.
    Send it my way if you like. ;)
     
  3. zx9

    zx9 Member

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    1 inch x 12tpi would fit a Drummond M
     
  4. eLuSiVeMiTe

    eLuSiVeMiTe Forum Supporter

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    10,438
    Location:
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    Nope. 8tpi apparently. Il check when home.
     
  5. Pete.

    Pete. Member

    Messages:
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    Location:
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    Are you sure that the thread is 1.75"? It's a very odd size for a spindle thread though it does fit some dividing heads. That faceplate wouldn't be for a dividing head though.

    Can you flip the face plate over and take a photo of it please with the tape measure? It might be suitable to re-machine for my South Bend
     
  6. eLuSiVeMiTe

    eLuSiVeMiTe Forum Supporter

    Messages:
    10,438
    Location:
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    Mine must be odd. 1 3/4 x 8tpi.
     
  7. slim_boy_fat

    slim_boy_fat Forum Supporter

    He hasn't actually said yet that he's selling, they'd surely be in the other forum section then? :dontknow:
     
  8. dan.taylor.1

    dan.taylor.1 General Tinkererer

    Only thing I want to keep is the 5" chuck, I was asking what they're worth. Tbh I'm open to offers on them, or swaps for lathe/mill tooling.
     
    slim_boy_fat likes this.
  9. dan.taylor.1

    dan.taylor.1 General Tinkererer

    I'll get a pic tomorrow when I'm at the workshop again. The best I could measure the minor diameter was 1.6" give or take a thou or 2, and measuring across the back of the thread looks to be 1.75".
     
  10. Scruffywelder

    Scruffywelder Member

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    Dumfries & Galloway
    I think 1"×12tpi is used on Myford ML8 wood lathes
     
    Tangledfeet likes this.
  11. Pete.

    Pete. Member

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    I have a headstock for one of those so I could check it out.
     
  12. Tangledfeet

    Tangledfeet Forum Supporter

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  13. Pete.

    Pete. Member

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    Double-depth for 6tpi is 0.289" so if the minor is 1.600" the major should be about 1.889", which is awful close to 1-7/8"
     
  14. zx9

    zx9 Member

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    3,736
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    This is also true, one of the few directly interchangeable parts in the Myford and Drummond ranges, shame the ML8 was a dead tree lathe as you point out. ;)
     
  15. Richiew Tungsten Sharpener

    Messages:
    811
    Location:
    Teesside, England
    1 3/4 x6tpi Whitworth fits the Denham DF4/ Henry Milnes lathes. I own one. If it is a square thread I think it fits the Raglan Little John. I don't think the faceplate is worth much as you only ever need one but you can't have too many chucks or back plates especially ones with obscure threads that don't come up often. I would pay good money if the back plate is the stated thread. New backplates with more common threads like this go for around 20/25 quid on Ebay.
     
  16. dan.taylor.1

    dan.taylor.1 General Tinkererer

    It's a normal 55° thread not an acme that's for sure, is there a better way I can check the thread diameter?
     
  17. Richiew Tungsten Sharpener

    Messages:
    811
    Location:
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    I'll check one of mine with my super accurate ALDI calipers and see what number comes up.
     
    zx9 likes this.
  18. Richiew Tungsten Sharpener

    Messages:
    811
    Location:
    Teesside, England
    Internal diameter from side to side. All fit on my lathe spindle.

    Backplate 1.540"
    Faceplate 1.541"
    Catchplate 1.545"
     
  19. Pete.

    Pete. Member

    Messages:
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    Location:
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    Richiew double depth of Whitworth 6tpi is 0.214" so your numbers add up spot on.
     
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  20. dan.taylor.1

    dan.taylor.1 General Tinkererer

    Looking again. I think the backplate may be 1 7/8" x 6tpi as its definitely 1.600" inside, the faceplate it's 1.551" inside. The clearance bore on the back of the faceplate is only 10 thou under that of the backplate at 1.810" compared to 1.820" so I'm moving clearer!!
     
    Anguz likes this.
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