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Thread: Question for turnere using Vacumn chucks

  1. #1
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    Unhappy Question for turnere using Vacumn chucks

    Occasionally I use a vacum chuck to hold a piece. The one I was doing yesterday is odd shaped and I was cleaning up the bottom. I was pulling 50-60 lbs of negative pressure, but keep losing the piece. Speed is 210 rpms(slowest speed available)

    Any ideas, so I don't put the piece back in the burn pile?

    Bruce
    Bruce Shiverdecker - Retired Starving Artist ( No longer a Part timer at Woodcraft, Peoria, Il.)

    "The great thing about turning is that all you have to do is remove what's not needed and you have something beautiful. Nature does the hard part!"

  2. #2
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    I don't use a vacuum chuck. But, I'll surmise a faster speed will help. That way you can lightly apply the tool to the 'shadow' and reduce catches and digs.
    That's a surmise. Wear yer face shield if you try my 'surmise' technique.
    "Folks is funny critters."

    Think for yourselves and let others enjoy the privilege to do so, too. ~Voltaire

  3. #3
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    calling vaughn.. your being paged!!!! i know he uses one alot bruce .. i would say from my vacuum experience that your not getting a good seal because once you get a good seal you cant pull it off a flat surface..
    If in Doubt, Build it Stout!
    One hand washes the other!
    Don't put off today till tomorrow!

  4. #4
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    Bruce, I agree with Larry. Sounds like you're not getting a good seal for some reason. What kind of wood it it? I've had some woods that were just to porous to hold with the vacuum. Is there any unevenness or warping on the part of the piece where you're attaching it to the vacuum chuck? Sometimes you can get it to grip uneven surfaces by adding a gasket of 1/4" or so closed cell foam between the chuck and the wood.

    I'm guessing you're just working on the foot area, and not turning out near the edge of the piece. When you say the piece is odd-shaped, what do you mean? Is it turned on a weird axis or off-center somehow? Holding an out of balance piece can be tricky, too.

    My fallback approaches for pieces that I can't get the vacuum to hold are to either use the vacuum chuck as a friction chuck with the tailstock holding the piece in place, or using stretch wrap or other tape to hold the piece to the lathe, usually held face to face with a rough turned bowl in the scroll chuck. (When I'm using the tape method, I keep the tailstock in place as long as possible, and use as low of speeds as I can.)

    And Frank, for a piece that keeps getting out of the vacuum chuck, increasing the speed is not a good idea. Although speed is handy when turning a lot of air (like on a winged bowl), we're typically using the vacuum only while we work on the very foot of the piece, away from any wings or other odd shapes or surfaces.
    When the going gets weird, the weird turn pro. - Hunter S. Thompson
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  5. #5
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    I agree with Vaughn. If I have a piece such as oak I will use saran wrap to get a better seal. If it is a offcenter piece I use the vaccum chuck as a jam chuck with the tailstock in place.
    Bernie W.

    Retirement: Thats when you return from work one day
    and say, Hi, Honey, Im home forever.

    To succeed in life, you need three things: a wishbone, a backbone and a funnybone.

  6. #6
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    It's gotta be a seal issue...shape, thickness, type of wood. Any pic's?
    Your Respiratory Therapist wears Combat boots

  7. #7
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    When I said 50-60 LBS, that is what the guage reads. The wood is Osage Orange. I'll add photosand possibly video tomorrow. Thanks for the comments so far.

    Bruce
    Bruce Shiverdecker - Retired Starving Artist ( No longer a Part timer at Woodcraft, Peoria, Il.)

    "The great thing about turning is that all you have to do is remove what's not needed and you have something beautiful. Nature does the hard part!"

  8. #8
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    Quote Originally Posted by Vaughn McMillan View Post
    Bruce, I agree with Larry. Sounds like you're not getting a good seal for some reason. What kind of wood it it? I've had some woods that were just to porous to hold with the vacuum. Is there any unevenness or warping on the part of the piece where you're attaching it to the vacuum chuck? Sometimes you can get it to grip uneven surfaces by adding a gasket of 1/4" or so closed cell foam between the chuck and the wood.

    I'm guessing you're just working on the foot area, and not turning out near the edge of the piece. When you say the piece is odd-shaped, what do you mean? Is it turned on a weird axis or off-center somehow? Holding an out of balance piece can be tricky, too.

    My fallback approaches for pieces that I can't get the vacuum to hold are to either use the vacuum chuck as a friction chuck with the tailstock holding the piece in place, or using stretch wrap or other tape to hold the piece to the lathe, usually held face to face with a rough turned bowl in the scroll chuck. (When I'm using the tape method, I keep the tailstock in place as long as possible, and use as low of speeds as I can.)

    And Frank, for a piece that keeps getting out of the vacuum chuck, increasing the speed is not a good idea. Although speed is handy when turning a lot of air (like on a winged bowl), we're typically using the vacuum only while we work on the very foot of the piece, away from any wings or other odd shapes or surfaces.
    I agree with Vaughn, sounds like a seal issue. The flat twine stuff (like clear wrap, but for wrapping pallets etc) is a very useful tool.
    The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails.
    William Arthur Ward

  9. #9
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    We had a demo from Donald a very talented member of our turning guild last weekend on making a vacumm system and i am set on attempting to make one myself. One thing that they showed for getting a good seal was stuff called fun foam from the craft store ( it`s like a sheet of foam gasket ). He said that the white stuff doesn`t transfer any color. Maybe this will work to solve your problem too.
    Daily Thought: SOME PEOPLE ARE LIKE SLINKIES..... NOT REALLY GOOD FOR ANYTHING BUT THEY BRING A SMILE TO YOUR FACE WHEN PUSHED DOWN THE STAIRS...............

  10. #10
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    Sorry I didn't get the pictures for you. My camera and computer are not talking. MY son, the computer GURU, is coming tomorrow for an egg hunt for my granddaughter and dinner. Hope we can figure out what's going on.

    Bruce
    Bruce Shiverdecker - Retired Starving Artist ( No longer a Part timer at Woodcraft, Peoria, Il.)

    "The great thing about turning is that all you have to do is remove what's not needed and you have something beautiful. Nature does the hard part!"

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