C-clamp thumb screw

Discussion in 'Sand Casting' started by Petee716, Oct 8, 2021.

  1. Petee716

    Petee716 Gold Banner Member

    I got a request from a friend to make a couple dozen thumb nuts(?) that he can fit to various c-clamps. I didn't ask him too many questions about his application yet. (He's an old tradesman and knows what he wants. He's 88 and has probably forgotten more than I'll ever know.)
    He wants them 3 inches long and with enough beef in the center to drill various sized holes for different sized clamp screws. Shaped like a "butterfly". I'm picturing something like this.

    My guess is that these are normally forged. I'll be discussing his end uses at some point with him to decide what material to use but I wanted to toss this out to the forum to get some ideas. I'll be sand casting. My material options at this point would be aluminum, everdur, or cast iron. Aluminum just seems wrong for the job. Bronze is awfully bendy, and CI might be too brittle. Old Ray is a woodworker though, so the last two options might still be reasonable.
    I might be able to get ahold of one to use as a pattern and make several duplicate patterns in hydrocal so I could cast half a dozen or so at a time.
    Any thoughts?

    Tobho Mott likes this.
  2. Wingnuts!, also a slang term for people with big ears in Australia. Why not make them in brass: stronger than aluminium, will bend rather than break and highly machinable.
  3. Melterskelter

    Melterskelter Gold Banner Member

    I do think you could also make them in CI. With that wingnut, he would be hard pressed :cool: to break them. Dropping them onto concrete would not cause them to break. Bronze would be very nice and I would think very capable. Also, polished up, bronze would be beautiful. Aluminum made with a good robust design would also work fine for for woodworking. I am thinking just a bit beefier flanges on the I-beam cross section. He might appreciate the light weight. Sounds like a fun project and probably gonna learn a thing or two along the way from this guy.

  4. DavidF

    DavidF Administrator Staff Member Banner Member

    I'd go with the everdur for the ductility..
    Plus you can braze to it...
    Tobho Mott and Petee716 like this.
  5. Petee716

    Petee716 Gold Banner Member

    That would resolve the attachment question.
    DavidF likes this.
  6. Petee716

    Petee716 Gold Banner Member

    I decided to cast it in iron. 6 molds. 1 success, 5 failures. Metal just not quite hot enough I believe.
    20211205_140148.jpg 20211205_143342.jpg 20211124_221801.jpg
    Tobho Mott and Mark's castings like this.
  7. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Like the flasks. You'll get'em next time Petee.

  8. Petee716

    Petee716 Gold Banner Member

    I first tried making multiple patterns with machinable wax but that was a no-go. Too much shrinkage. Then I spotted a length of soil pipe that fit the bill nicely. I hope to get productive use out of them. The cost of the clamps added up.

  9. DavidF

    DavidF Administrator Staff Member Banner Member

    Or you forgot to say the magic words.....
  10. Melterskelter

    Melterskelter Gold Banner Member

    Ohhh so close! Sure looks like it was just a tic cool.
    Yup, next time.


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