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Thread: 1/2-24 thread mounting drill chuck

  1. #1
    Join Date
    May 2004
    Posts
    3

    Post 1/2-24 thread mounting drill chuck

    Anybody out there know where I might find a drill chuck that mounts to a 1/2-24 thread?
    Chuck on old "Champion" (I think) drill press needs replacement.

  2. #2
    Join Date
    Apr 2004
    Posts
    237

    Post

    I just want to verify that it is a 1/2 - 24 and not a 1/2 - 20 thread as the former is a National special thread and the latter is a National fine thread being more common and there are lots of chucks with this thread size. There is only .008 difference between the two thread sizes when measuring from thread to thread or a simple mismatch between thread pitch gages if the threads are damaged or dirty. I don’t know your background or experience level so please do not take this insult to your skill level I just wish to point out some possibilities. If not a simple threaded adaptor may have to be made as I did a quick search and came up blank for 1/2 - 24 threads.

    Mike

  3. #3
    Join Date
    May 2004
    Posts
    3

    Post

    Mike:
    Thanks for your reply.
    Checked pretty carefully W/ thread gage. I've seen through my own searches that 3/8-24 & 1/2-20 are the current standards and I haven't seen anything else. I have an old (40's, I'd guess) Craftsman table saw for which I had to make a 1/2-24 arbor nut; I thought perhaps this thread may have been in wider use in the past. -May well have to make an adaptor but since this is a small tool trying to keep thingd compact.
    -Marc

  4. #4
    Join Date
    Jan 2003
    Posts
    3,641

    Post

    Marc,

    Back in the early eighties I was able to buy a 1/2" drill chuck with 1/2-24 thread off the shelf at a local tooling house. I remember being surprised that they had it in stock, but they said it was a standard item for them.

  5. #5
    Join Date
    May 2002
    Location
    Texas
    Posts
    10,761

    Post

    Marc,

    I don't know of any source for that size.

    I needed/wanted a larger chuck for my Unimat which used a M12 x 1 thread. I purchased a 1/2" Jacobs chuck with a 3/8" thread and bored it out, threaded 90%, and tapped. They have pleanty meat in the back end so this will work just fine. 1/2 is only slightly larger than 12mm so should be no problem.

    I mounted it in the lathe using the chucks own jaws tightened on a piece of stock in a 3 Jaw that was first turned concentric (tighten progressively at all three positions around the Jacobs chuck). Worked out pretty well but not perfect. You might be just as good or even beter gripping the outside of the chuck with a 4 jaw and dialing it in. I did all the work on the Unimat itself, so it can be done on any size lathe.

    Paul A.
    Paul A.

    Make it fit.
    You can't win and there is a penalty for trying!

  6. #6
    Join Date
    May 2004
    Posts
    3

    Post

    Thanks all for the ideas.
    The drill press in question is a "Companion", not "Champion" as I earlier erred. I'm told it was bought from Sears in the early 40's and that Companion was a cheaper line than the Craftsman line. It's a hand tightening chuck of the simple spring loaded jaws in cone type. The 1/2-24 thread, therefore, facilitates tightening the chuck as well as holding it on.

  7. #7
    Join Date
    May 2002
    Location
    Texas
    Posts
    10,761

    Post

    McMaster Carr, (732) 329-3200, invites inquiries of this type. I have have used their research abilities in the past with good luck. You might give them a call or get their e-mail from their web site: www.mcmaster.com

    Paul A.
    Paul A.

    Make it fit.
    You can't win and there is a penalty for trying!

  8. #8
    Join Date
    Oct 2004
    Location
    DFW Texas
    Posts
    1,012

    Post

    Marc
    I have what is probably a Companion hobby lathe of about the same vintage. It has a spindle thread of 1/2-24.

  9. #9

    Post

    1/2-24 thread, boy did I learn the hard way! I recently rebuilt my old craftsman woodworking spindle shaper. The bearings were no longer available so I bought metric size equivalents that fit the casting, and decided to make a new 1 piece spindle to match the bearing ID. Mic'd the old thread - 1/2" - got to be 1/2-20 right? Made the spindle from drill rod, went to screw on the original nut that holds the cutter on the spindle and she won't go. NOW I get out the pitch gage and see it's a 24. Chucked up some hex stock and made a new nut. Oh well, every day's a new adventure.
    Bob

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