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Thread: Donut chuck???

  1. #1
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    Donut chuck???

    I sat and watched Bill Grumbines video again last night so I finally took some time to go out and turn something on my lathe. I have a lot to learn but so far so good. I have a bowl mostly done but need to take it out of the chuck and finish off the bottom including cutting away the tenon. I have two sets of cole jaws on two different chucks that I had purchased for this reason but both are too small for this bowl. Is a "Donut Chuck" the way to go now? I watched Bill use just a friction chuck in his video. So what do you all like to use?
    It's not what you achieve in life...It's what you overcome!

  2. #2
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    Tom, I use a vacuum chuck when possible. Second choice is a jam chuck that lets me nearly complete the bottom and leaves just a small nub to saw off, then hand sand to finish. I don't have a doughnut chuck, but would build one of the need arose. I think it depends on what you are most used to turning and then you build your technique to suit your style.

  3. #3
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    Tom, I have a donut chuck with a variety of different-sized rings. It's a handy way to finish bowl bottoms, although I seldom use mine anymore. These days I typically use a friction chuck like Bill does in the video, or a vacuum chuck. For someone starting out, a donut chuck is worth the time it takes to make one.
    When the going gets weird, the weird turn pro. - Hunter S. Thompson
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  4. #4
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    I keep thinking I will make a donut chuck and something else always seems to come I do think it is the way to go. I just use friction/compression probably about the same as Bill G. did. The only problem is with a small foot being able to put a design in and still sand. Guess I need to also buy a 1” sanding disc.

    But first, my trammel-chuck layout gauge, Swiss-army lathe wall cabinet, three point rotational dust hood, and….. just doesn't end.
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  5. #5
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    Well Ted...I have no style and not much technique. I dont have a vacuum pump so thats out......If you use a jam chuck...you still have to use the tail stock correct? So I assume you just turn it as close as you can then remove from lathe and cut or sand down the nub thats left?
    It's not what you achieve in life...It's what you overcome!

  6. #6
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    Yup, you still use the tail stock and do just exactly as you assumed. Use your own judgement on the size of the nub to leave...usually something on the order of 1/2" diameter or a little smaller depending on the mass of what you are turning. I have one of those flexible japanese style pull saws that I use to cut off the nub, then power sand with 2" discs to finish. Just be careful not to make the nub so skinny it accidentally breaks off during sanding, because then the torn fibers could extend into the bottom of the object beyond the point where they can easily be sanded out.

  7. #7
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    Quote Originally Posted by Tom Baugues View Post
    ...If you use a jam chuck...you still have to use the tail stock correct? So I assume you just turn it as close as you can then remove from lathe and cut or sand down the nub thats left?
    That's correct. You typically use the tailstock with a friction/jam chuck. Actually, some guys make a jam chuck that's perfectly sized to hold the bowl without the tailstock, but that's more work than I'm interested in doing.

    Here's a series of pics showing how I often do it...

    This is a box elder bowl. This shot shows the tenon:



    For the friction chuck, I'm using my vacuum chuck, but it's not hooked up to the vacuum pump. I add a ring of wetsuit material just as padding, to keep from denting the soft box elder wood:



    Using the tailstock with moderate pressure to keep things in place:



    As I whittle down the tenon, I define the area that will become the recessed (concave) foot. This is also when I'll do my final sanding on the lower parts of the bowl. You can see in this pic I still have some sanding to do, but in the next pic the sanding is done:



    Then I continue turning the nub smaller and smaller, until it's a cone. Typically, I'll turn the cone tip down to about 1/8" then make additional cuts and do some sanding to further refine the foot. With harder woods like maple or cherry, you can get the point of the cone down to about 1/16" or smaller before it lets go. In this photo, the wood gave way and the cone came loose sooner than I wanted, so I didn't get a chance to dress up the foot the way I wanted to:



    This photo is from a different bowl, but it shows how small I typically make the point of the cone:



    Once the cone lets go, any additional finishing is done off the lathe. Here, I used a chisel to trim the leftovers from the cone. In most cases, I don't use a chisel because I'm able to make the final cut cleanly while it's still spinning on the lathe.



    Obligatory action shot:



    Then a bit of power sanding to finish up:



    And it's ready for signing and dating:



    Does that help explain it?
    Attached Thumbnails Attached Thumbnails IMG_0844 - 800.jpg   IMG_0847 - 600.jpg   IMG_0848 - 600.jpg   IMG_0850 - 600.jpg   IMG_0852 - 600.jpg  

    IMG_0853 - 600.jpg   IMG_0855 - 450.jpg   IMG_0857 - 600.jpg   IMG_0861 - 800.jpg   Bowl 092 - 11  600.jpg  

    When the going gets weird, the weird turn pro. - Hunter S. Thompson
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  8. #8
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    Wow Vaughn, thank you very much for the great detailed photos. Although I have not even tried it yet I'm afraid of it breaking off sooner than I would want and sending the nearly finished bowl flying across the room putting lots of dents and dings into it. I suppose experience plays a big part here and the more times you try it the better (presumably) I would get. Well, I'll have to give this some thought tomorrow and come up with a plan.

    I do have another question for anyone.....does using the jam chuck inside the bowl mar up the already finely sanded interier of the bowl? I assume as long as I use a good padding like a router pad I assume it would be ok.
    It's not what you achieve in life...It's what you overcome!

  9. #9
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    Tom you can also use anything heavy rubber type material - I got a thick rubbing kneeling pad at the thrift store for $1.00 used in excerise classes. The thrift stores also may have a used wet suit and that would work just as good.
    The kneeling pad is big so i am able to cut small squares to use for sanding blocks that will mold in a curved way for sanding etc......
    Try the thrift stores or something like it for bargins on material like this...................................
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    Then you have to learn advanced rules - Professional
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  10. #10
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    Quote Originally Posted by Tom Baugues View Post
    ...I do have another question for anyone.....does using the jam chuck inside the bowl mar up the already finely sanded interier of the bowl? I assume as long as I use a good padding like a router pad I assume it would be ok.
    Yeppers, padding is a good idea. Like Dan said, just about any type of padding will work. I use a few layers of folded router pad (aka rubber shelf liner) pretty often. I've also used "Fun Foam" closed-cell foam sheets from Michael's. Some old mouse pads will work, too. For smaller bowls, I've just put a pad over the 4-jaw chuck and pushed the bowl down onto it. The wetsuit material I sometimes use with my vacuum chuck also works nicely. The vacuum chuck has rubber seals, but if I'm using the vacuum, the hard plastic shell can dent softer woods.

    As far as practicing to get the nub smaller and smaller, it's something you can build up to. When I started doing it, I'd take it down to about 1/4" diameter then saw through the rest with a flexible flush cut saw. (You can bend the blade and actually saw into the recess of the foot if you're careful.) As time went on and I got more comfortable with my detail gouge, the point of the cone got smaller and smaller, until I started cutting all the way through. I make sure I'm running the lathe at relatively low speeds, and I have my remote switch close at hand so I can turn off the lathe quickly when the gouge cuts through. Nearly all of the time, the cone point stays centered and the lathe spins down to a stop without the bowl getting off center. The rare times that it does go caddy-whompus, it has only been slightly off center, and I was able to stop the lathe before the bowl was damaged.

    It's important for the cut to be a shearing cut, with the cutting edge nearly vertical. If you hold the gouge with the flute up, you run a big risk of a catch, followed by bad words. This pic shows how I have the flute of the gouge pointed to about 9 o'clock. I alternate between 9 o'clock and 3 o'clock as I work the cone down in size. (This particular bowl had a rounded bottom with no foot.)



    That all said, this is not a technique to try for the first time on an important bowl. The potential does exist for it to go bad in the end.
    Attached Thumbnails Attached Thumbnails Bowl 092 - 09  600.jpg  
    When the going gets weird, the weird turn pro. - Hunter S. Thompson
    When the weird get going, they start their own forum. - Vaughn McMillan

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