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Thread: When to Use a drilled recess for chuck jaws

  1. #1
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    When to Use a drilled recess for chuck jaws

    I'd be interested in knowing how the drilled recess performs when turning, since there is no dovetail? Also, when do you drill as opposed to cutting in a dovetail recess.

    Thanks
    Joe

  2. #2
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    So far, I have been turning a dovetail to match the jaws of my chuck.

    But your post made me think. If I was using green wood or a dry soft wood I would think that the dovetail of the jaws would deform the wood. It would probably hold just fine - - assuming no major catches. But if I was using a dry and very hard wood (e.g., eucalyptus), there wouldn't be any significant amount of deformation and it would be held less securely.

    I'm not sure if I'm going to switch my technique though because the tip of my forstner bit leaves about 1/8th inch impression in the finished hole and that means that I eventually would have to turn off that 1/8th inch.

    Thanks for starting this thread. I look forward to reading the responses of others who used drilled holes with their dovetail jaws.

  3. #3
    I imagine it would be fairly straightforward to drill the recess, then use a dovetail tool (a few pictures popped up in a thread just a couple of days ago) to add a dovetail without really affecting the diameter or the drilled recess.

    Best of all worlds-- saves time, still get a flat/clean bottom, has the dovetail for a solid grip.
    Licensed Professional Engineer,
    Unlicensed Semi Professional Tinkerer

  4. #4
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    Quote Originally Posted by Brice Rogers View Post
    ...Thanks for starting this thread. I look forward to reading the responses of others who used drilled holes with their dovetail jaws.
    Brice, I wrote something on the Joe's same question earlier today in another thread. The message with the question disappeared since then which confused me at first but this is what I wrote:
    http://www.sawmillcreek.org/showthre...25#post2726625

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    Quote Originally Posted by Joe Frank Porter View
    I'd be interested in knowing how the drill recess performs when turning, since there is no dovetail? Also, when do you drill as opposed to cutting in a dovetail recess.
    Joe,

    My experience: in softer wood like walnut, cherry, soft maple, etc. the dovetail of the chuck jaws presses into a drilled hole in the wood and forms it's own "dovetail". For me this has worked very well - I've never had one come off. If it is ever necessary to take it off the jaws and remount and hope to have it even close to registered (iffy at best, regardless) you have to make sure the jaws are in exactly the same place.

    I prefer to drill when my blank is flat on both sides (cut from a plank), quicker, especially if I'm doing a bunch. I usually cut the recess on the lathe if just doing one piece, especially if the blank is held by a screw chuck.

    If the wood is hard like osage orange, black locust, and lots of exotics I will cut a dovetail since there is little give to the wood. Also, the dovetail makes sense for large and heavy blanks. In addition, if the jaw diameter is not very close to the recess diameter the dovetail will help hold more securely. One more thing - I knew a turner who was horrible at tool control - I saw the same bowl come off his lathe three times. He needed a good dovetail (and to learn how to turn without catches!) That's all I can think of at the moment.

    JKJ

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    As for the little divot made by the Forstner bit if the blank is held by the other side (screw chuck, etc) when I make the recess I usually cut that away with a little dished cut since at the end I often like to use tailstock support to turn the bottom and the tailstock is in the way then. This one is probably not typical since I decided to leave a slightly raised flat "donut" around the center but the idea is the same - easier to turn the hole away at this point then I'm not guessing at the bottom thickness when hollowing.

    BOC_demo_bot_IMG_6703.jpg

    I use a small flexible plastic disk for the tailstock to bear against so it doesn't mar the bottom, but a little piece of soft wood would work too.

    JKJ

  5. #5
    I always use a drilled recess for mounting my bowl blanks. I only use them for turning the outside of the bowl. I do generally drill down far enough, so that when I put the bowl blank on, the flat surface will sit on the face of the chuck jaws. This would be 1/2 inch plus deep with my Vicmark chuck. This is a recent thing for me to drill deep enough for this type of seating. Mostly, when cutting blanks, I focus on the top of the bowl, and would rather even up the bottom of the blank rather than having to even up both the top and bottom. For the recess on the bottom of the bowl, I always cut that in with a dove tail scraper, and do finish cuts on it so sanding is minimal. It is my finished bottom. The dove tail gives a much more secure grip on the bowl blank. Given my hogging off technique using scrapers, and I core any thing of size, this extra security is a must. If I was going to turn off the bottom, then I would use a tenon.

    robo hippy

  6. #6
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    Not lost John, it’s right here.

    http://www.sawmillcreek.org/showthre...50#post2726450
    Have fun and take care

  7. #7
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    Quote Originally Posted by Leo Van Der Loo View Post
    Thanks for checking, but no, that's not the message, it's not even the same question. The message was right about here in Brandon SPEAKS thread with the title "drilling reces":

    missing_message.jpg

    When I went back to look at it I was confused for a bit then I figured that Joe deleted it and started over in a new thread, this one. Either that or the playful spirits of woodturning forums thought it would be a good joke. Either way, not an issue.

    JKJ

  8. #8
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    Quote Originally Posted by Joe Frank Porter View Post
    I'd be interested in knowing how the drilled recess performs when turning, since there is no dovetail? Also, when do you drill as opposed to cutting in a dovetail recess.

    Thanks
    Joe
    Joe I never drill the recess and also never use the dovetail shape in any of them, I heard all the reasons turners give for using them for years already, mind you I’m not the kind of turner that tries to get all that wood out of the bowl in the shortest possible time.

    I am not or ever was a production turner, it has always been the love turning, and for nearly 60 years already, it has evolved from using scrapers, (as the bowl gouges we all use now where not invented yet) to using the HSS bowl and spindle gouges now.

    I start with a faceplate to rough turn the outside, (Always from fresh green wood) and cut the recess with my bowl gouge and clean the corner of it with a scraper, the wall of my recesses are always at 90 degrees to the bottom or a slight bit more than that.

    Most times the bottom of the recess is just a hair lower than the outside of the bowl surface, and I use just one hand on the chuck key to tighten it, going around a couple of times if I feel that the wood gives, but never crank it hard.

    I don’t loose bowls (mind you catches are few and far between and should be by now I guess , the dovetail shape is much overdone, the shape of my Oneway chuck jaws are also not a dovetail shape (They are available if you insist) and are holding just fine.
    Last edited by Leo Van Der Loo; 09-14-2017 at 4:19 PM.
    Have fun and take care

  9. #9
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    John, You got the correct answer. You win. I originally posted my question in the other thread, but since I was late posting my reply/question, I decided to post as a new thread. Sorry for the confusion.

    Thanks,
    Joe

  10. #10
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    Thanks all for your informative replies.

    Joe

  11. #11
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    Quote Originally Posted by Joe Frank Porter View Post
    John, You got the correct answer. You win. I originally posted my question in the other thread, but since I was late posting my reply/question, I decided to post as a new thread. Sorry for the confusion.
    No problem! I try to read all the posts so I saw both and figured that happened. A new thread makes better sense for your question.

    Wait, is there a prize??! I'll take a new American Beauty lathe, or I guess an 8' log of african blackwood would be ok.

    JKJ

  12. #12
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    Being lazy I usually start a bowl on a single screw or small faceplate--reverse and cut a chuck recess and cut he bottom. Easy when you can see the whole bottom. A single screw is the fastest mounting possible and the screw hole is to be hollowed anyhow!

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