bowl turning

Discussion in 'Newbie' started by Dave Fritz, Feb 3, 2017.

  1. Dave Fritz

    Dave Fritz

    Joined:
    Sep 12, 2014
    Messages:
    125
    Location:
    Wisconsin
    When I finish turn a bowl I first reshape the tenon, then finish the bottom 1/3 of the bowl. Then I turn the bowl and mount it in the chuck. I first finish turn the outside and rim. I also sand as much of the outside and rim as I can reach.

    When I turn the bowl I use my vacuum chuck as a jam chuck and use the tail stock to hold it until I want to remove the tenon, then I use the vacuum chuck and take the tail stock away.

    I've noticed that when I get to the final step the outside has moved due to moisture loss or tension in the wood. Usually I don't try and do anymore to the outside because there isn't much support

    I have two questions:
    1) Is this process similar to the process you use
    2) Do you try and finish the outside in the final step or allow for some slight irregularity.
     
  2. John Torchick

    John Torchick

    Joined:
    Jan 24, 2010
    Messages:
    1,135
    Location:
    Southeast Tennessee
    Interesting questions. Waiting for answers as I am also interested in this as a new turner.
     
  3. hockenbery

    hockenbery AAW Advisor Staff Member

    Joined:
    Apr 27, 2004
    Messages:
    4,311
    Location:
    Lakeland, Florida
    Home Page:
    There are many ways to turn a dried bowl. I do a lot of what you describe. I also do a few things you did not mention.

    My method is a combination of things I learned from other turners. It will work for anyone who uses it. I balance the rim when I first remount it. The advantages of doing this is I get the largest bowl possible from the dried bowl and I get the warped bowl about as balanced as it can get.
    The first turning I do with a dried bowl is true the rim(the most out of round part) then the bowl will run faster with less vibration.

    @Dave Fritz if you have dried your bowl to <10% MC it should not move when being returned. It is possible to deform a bowl with the vacuum although they usually crack when deformed much. Also I when returning the hard dry wood it is possible to turn it out of round with too much bevel pressure.

    In January I did a demo for the tricounty Woodturner's. I rough turned a green bowl and mounted and turned a dry bowl. I did not sand it. Being a small bowl 10-11" diameter it will be easy to sand off the lathe.

    Link to video of returning the dried bowl


    View: http://www.youtube.com/watch?v=sCZWsHB4vlM
     
    Last edited: Feb 3, 2017
  4. dbonertz

    dbonertz

    Joined:
    Oct 16, 2007
    Messages:
    277
    Location:
    Fort Collins, CO.
    I agree with Al has said with one caveat. Even dried to 10% moisture you can expect a little movement in most woods. Just by the act of cutting the fibers will release some tension and thus minor warping.

    Turning the bowl around and putting it in the chuck to turn the inside will also make it appear out of round. Even with the best made tenon you will most likely experience a bit of out of roundness. Typically a shear scraping cut will retrue it and you can go about your business.
     
    odie and Bill Boehme like this.
  5. Dave Fritz

    Dave Fritz

    Joined:
    Sep 12, 2014
    Messages:
    125
    Location:
    Wisconsin
    The point about moisture is well taken. In a DVD on pepper mills the demonstrator put both pieces of his mill, after rounding and parting off, in a refrigerator kiln to be sure the moisture was at 10% before he completed the mill.

    Dale, to your point, even as you remove wood from the inside I find the outside will move due to the tension released from the removal of the interior wood. I suppose a lot depends on the species of wood too.

    Thank you both for your responses, they're very helpful.
     
    odie likes this.
  6. john lucas

    john lucas

    Joined:
    Apr 26, 2004
    Messages:
    5,830
    Location:
    Cookeville TN USA
    All very similar to what I do as well. Wood does move. I make my mirrors out of Kiln dried wood and they usually sit in the shop a while. Still after I turn them and glue in the glass which is perfectly round I can detect a slight oval to the opening. It's not much at all but definitely no longer round. I usually mount my roughed bowls between centers and adjust it so the rim is as even as I can and the tenon is also. Then I true up the tenon and turn the outside. Then I mount it in the chuck to do the inside. One thing I do when mounting the bowl in the chuck is to orient the grain in a sort of X pattern so that each jaw has the same amount of end grain and side grain in contact with the jaw. That is assuming a side grain bowl by the way.
     
    Bill Boehme likes this.
  7. RichColvin

    RichColvin

    Joined:
    Mar 13, 2016
    Messages:
    129
    Location:
    Dublin, OH
    John,

    How do you accommodate the wood movement on hand mirrors to prevent breakage?

    Rich
     
  8. Bill Boehme

    Bill Boehme Administrator Staff Member

    Joined:
    Jan 27, 2005
    Messages:
    8,139
    Location:
    Dalworthington Gardens, TX
    Home Page:
    I've used GE Silicone II because it doesn't contain acetic acid like some other silicone caulks, but there may be better products. Gluing at only the center and not the entire surface is one way to deal with wood movement issues.
     
  9. Dave Fritz

    Dave Fritz

    Joined:
    Sep 12, 2014
    Messages:
    125
    Location:
    Wisconsin
    Al, thank you for the excellent video. It was well done and easy to follow your process and thinking. I look forward to viewing more of your videos.
     
  10. hockenbery

    hockenbery AAW Advisor Staff Member

    Joined:
    Apr 27, 2004
    Messages:
    4,311
    Location:
    Lakeland, Florida
    Home Page:
    I appreciate the kind words.
    Much of the credit goes to Jan and Carl Brown.
    Jan is behind the camera working really hard and Carl does all the set up and cleans the water off the camera lens.

    Again this is my method and my go to tool is the Ellsworth ground Gouge.
    Many successful turners use similar techniques and a similarly ground gouge.
    There are lots of other tools and methods that work and some that don't.

    Have fun and be safe
     
  11. john lucas

    john lucas

    Joined:
    Apr 26, 2004
    Messages:
    5,830
    Location:
    Cookeville TN USA
    Rich I undercut the wood at the lip. Then I use bevel edge mirrors. I Leave the opening just a hair bigger than the glass. If the wood shrinks the glass simply goes into the under cut. I use a parting tool to cut the opening. Then I take my Thompson detail gouge and rub the bevel with the flute pointing horizontal. Then I just push it into the cut left by the parting tool. I twist it clockwise which lets the lower wing do the cutting of the undercut. Then I lower the handle keeping the lower wing in contact with the wood. This now becomes a shear scrape and I pull it out and round over the lip which cleans up the torn grain by the parting tool and shapes the lip at the same time.
     
  12. Tom Albrecht

    Tom Albrecht

    Joined:
    Feb 8, 2014
    Messages:
    411
    Location:
    Midwest USA
    Hockenbery, that was a great video, really one of the best I've seen on turning a dry blank. No, it IS the best. It makes me wonder why we have this "NEWBIE" section? That video should be in the Main forum-- it ain't just for Newbies.
     
    Last edited: Feb 9, 2017
  13. hockenbery

    hockenbery AAW Advisor Staff Member

    Joined:
    Apr 27, 2004
    Messages:
    4,311
    Location:
    Lakeland, Florida
    Home Page:
    Thanks for the kind words. I posted a thread in the techniques for this video.
     
  14. Bill Boehme

    Bill Boehme Administrator Staff Member

    Joined:
    Jan 27, 2005
    Messages:
    8,139
    Location:
    Dalworthington Gardens, TX
    Home Page:
    The short answer to your question about why we have a separate Newbie forums originated when a number of new turners felt like the main forum (which was the only forum at that time) was too oriented towards the "professional" turners and wanted a place where they could feel more comfortable sharing and asking questions. I don't want to derail the thread so I will expand on this in another thread.
     
  15. MichaelMouse

    MichaelMouse

    Joined:
    May 16, 2005
    Messages:
    3,540
    Nope, not the way I do it. I use a mortise inside and outside. Green roughs and cured bowls are done the same way. The inside one starts a green 1", so I drop a forstner down to make it round and centered again. Mount the piece, turn the entire outside, including sanding.

    http://i35.photobucket.com/albums/d160/GoodOnesGone/Method-One.jpg
    Can't be anything but centered perfectly after reversal, as the jaw faces bear on the bottom of the mortise and the dovetail sides wedge/hold it firm.
    http://i35.photobucket.com/albums/d160/GoodOnesGone/Method-Two.jpg
    When shape and thickness are as desired, and the piece at circular and as light as it will get, out comes the tailstock support.
    http://i35.photobucket.com/albums/d160/GoodOnesGone/Method-3.jpg

    Even the warp and go green turns are prepared the same way.
    http://i35.photobucket.com/albums/d160/GoodOnesGone/Bark-up.jpg

    Pieces are always secured at both ends until their lightest and best balanced, so it's a great safe method which allows me to stay out of the throw zone. I use the pin chuck, though lighter work will do fine with pin jaws or woodworm screws. They don't drift off center unless it's a truly mangled grain piece.
     
  16. Bill Boehme

    Bill Boehme Administrator Staff Member

    Joined:
    Jan 27, 2005
    Messages:
    8,139
    Location:
    Dalworthington Gardens, TX
    Home Page:
    Thanks for the information, @MichaelMouse.

    Would you consider attaching the images to your post rather than the links to Photobucket? The reason for my request is that Photobucket has become almost intolerable with their pop-up advertisements and other annoyances. I clicked on the first link from my iPad and had heck closing all the pop-ups. I haven't tried it from my PC yet, but McAfee is pretty good about blocking annoying content.
     
  17. hockenbery

    hockenbery AAW Advisor Staff Member

    Joined:
    Apr 27, 2004
    Messages:
    4,311
    Location:
    Lakeland, Florida
    Home Page:
    The center post is an old and effective method of turning a bowl without a chuck or faceplate just using a spur drive and dead center. I mentioned it when answering a question in the demo video.

    While the center post method works, I don't recommend it to students because it is too slow and and not useful for a variety of bowl shapes.
    You are right that it's big advantage is being a solid hold for folks getting big catches.
    Average students don't get catches.

    As a practical matter the technique is pretty much limited to open some what shallow bowls. Anyone who intends to core bowls will find the center post a poor method to use. Anyone who wants to turn deep bowls, closed rim bowls, or calabash style bowls will find the technique a poor or unusable choice.
     
    Last edited: Feb 16, 2017
  18. Mike Johnson

    Mike Johnson

    Joined:
    Jul 26, 2016
    Messages:
    619
    Location:
    Nebraska
    I like to use a recess in the bottom of the bowl and a tenon on the inside of the bowl for 1st turnings.
    I always leave a center mark on the recess and the tenon so there is reference for the center of the blank.
    The center point allows centering the blank between centers and cleaning up the recess or tenon as needed.
     
  19. MichaelMouse

    MichaelMouse

    Joined:
    May 16, 2005
    Messages:
    3,540
    The method comes from the practice of hammering a pin into the center of the piece to use with a reciprocating type lathe. Rope wraps around it. VERY old practice. https://www.bing.com/videos/search?...E6D80C2ED1E2B4AD15A9E6D80C2ED1E2B4A&FORM=VIRE Answer to small opening bowls is there as well. Folks used hook tools. Termite or scraping types work for the moderns.

    Takes near NO time to bore a 1" hole and tap onto the pin chuck/jaws. About as fast as putting a single screw on a faceplate. Not sure what else you do to take up time. Agree it's belt/suspenders having both ends mounted. But it never works loose with the pin chuck, and with the regular scroll chuck, it doesn't wobble off the shoulder of a tenon or from the bottom of a mortise on off-center unbalanced turnings. Great choice if you catch, too.

    I turn bowls 16X9 on it. That's about as deep as the average folks are able, I figure. It is for bowls, not "hollow forms," which, of course is an answer to another question. For those who core, The outside of the main is still fully turned before reversing, and supported by the tailstock center while coring. Haven't come up with a reason to do otherwise. As a matter of fact, being able to cantilever the first core in reverse to prepare a perfectly centered hold and bottom seems advantageous. Check the video for coring, old style.
     
  20. hockenbery

    hockenbery AAW Advisor Staff Member

    Joined:
    Apr 27, 2004
    Messages:
    4,311
    Location:
    Lakeland, Florida
    Home Page:
    @MichaelMouse no question it works well for open bowls. A really good idea for anyone using a mortise hold where using the tailstock will prevent breaking out.

    I'm sure you can drill a hole about as fast as I can seat a spur drive.
    its the turning that is slow with the post.

    By deep bowl Think deeper than wide
    Do an 8" tall 5" wide bowl with your method. It could be done but just not practical.
    Do a calabash style bowl. A spherical bowl.

    Another issue, once you bore a hole you are stuck with that grain pattern.
    The post also limits getting the tool rest into the bowl.

    It just isn't a technique that works well for the variety of bowl shapes that can be turned with a side ground gouge. It is also a much slower method of hollowing a bowl.

    Compare the hollowing on this bowl mounted on a tenon with your post method.
    Remember demo time runs about 3x shop time.

    View: http://www.youtube.com/watch?v=flw8LwQqGQU
     
    Last edited: Feb 18, 2017

Share This Page