first open segment bowl problem

Discussion in 'Open-Segment Turnings Forum' started by Rod Smith, Jan 8, 2018.

  1. Rod Smith

    Rod Smith New Member

    I glued up my first attempt to do an open segment bowl. It lasted one minute before I caught a piece and it blew apart. I was not really happy with the glue up so I am gluing up another one and so far it is looking good. I went from 1/2 inch thick segments to 3/4 inch thick and I made the wall thickness thicker. I have been looking for web sites that would help me with techniques and tools to use with open segmented bowls but have not had any real success. Any help to make my next attempt better. I know about the Hunter osprey tool but I don't have one. I have carbide tools ( small and large round, square and diamond).
     
  2. Bob Beaupre

    Bob Beaupre Administrator Staff Member

    Do you have pictures?
    What diameter is it, how many segments per row?
    What does your set up look like?
     
  3. Rod Smith

    Rod Smith New Member

    six inch diameter, 18 segments per row. I don't know what you mean by set up.
     
  4. Bob Beaupre

    Bob Beaupre Administrator Staff Member

    Are you turning on a face plate or using a chuck.
    Did you have it between centers or just supported from the head stock
    How fast were you turning it
    What tool were you using
    Did you sand off the sharp points on the segments
    How heavy of a cut were you taking
    How much overlap did you have from row to row
    What kind of glue are you using
     
  5. Rod Smith

    Rod Smith New Member

    Turning on face plate
    Just supported on headstock.
    slow rpms
    Small round carbide
    I did not sand sharp points
    Trying to do light cut
    Overlap was more than what i would have liked.
    Titebond II
     
  6. Jeff Miller

    Jeff Miller Moderator

    You have probably heard this before, but very sharp tools and a light touch work best. It can be difficult to control the depth of cut on open segments, especially if the speed is too slow. I try and turn at the highest speed that I feel comfortable with at the time.
     
  7. Bob Beaupre

    Bob Beaupre Administrator Staff Member

    As Jeff has said slow RPM can cause deeper than expected cuts, so a medium speed work probably would work better. Also, that small round carbide is basically a scraper and that can be awful grabby at low RPMs. Remember on segmented turnings you are turning all side grain and you could use a spindle gouge. If you put the tip into a high shear angle (handle way low) trying to keep the tool riding the bevel you may have more success, then you are cutting with the sharpest edge of the tool. And keep the tool sharp, you are going thru a lot of glue and that will dull the tool fairly fast.
     
  8. Arlin Eastman

    Arlin Eastman Member

    Rod

    It seems by what you wrote you have a tool presentation problem. For all scrapper work the scrapper needs to be lower then the center point or you will get a catch. I would suggest raising the tail stock 1/4" higher and that should take care of it. Plus scrappers are mostly used for clean up duty. If you learn how to use a bowl gouge this should also help you a lot in all turning.

    I was very fortunate that Lyle Jamieson came to my house 3 times to help me in my turning and also set up my grinder the right way and Jimmy Clewes also came to my house to show things he knows to.

    If you wish I can loan you a few DVDs of their to help you learn how to use it better. Just send me a PM with your mailing address. Also turning at the highest speed you feel comfortable with you will get much better cuts and smoother cuts as well.
     
  9. Lloyd Johnson

    Lloyd Johnson Administrator Staff Member

    You should not be in a hurry to turn an open segment bowl. The rows do not get locked into place until there is a new row on top of it. If you do need to do some turning, avoid turning the top row because it is not locked. Once you add a closed segment ring to it, the entire bowl will turn like it is a closed segment bowl.

    If you are using a gouge, always turn towards the bottom of the bowl. If you turn away from the bottom of the bowl, you are putting upward pressure on the segments which is doing its best to pop them off the turning.

    So if you have to turn the bowl because it will be difficult to reach the bottom, only turn the inside and start from the row beneath the top row and turn towards the bottom of the bowl.

    When it is time to turn the outside, you want to leave as much mass at the bottom of the bowl as possible so start your turning at the top row and work downward.

    Remember that an open segment bowl is fragile by nature and if you remove mass from the bottom, the lower rows may not have the strength to hold the bowl together.

    To get better at this, make open forms with just a few rows. Put a closed segment row on it and start at the top and you’ll have no problem at all. It is up to you whether you want to start with the outside or the inside but experience tells me that turning the inside is the biggest chance for failure so I tend to turn it first while I still have the mass of the bottom of the bowl in place.
     
  10. Rod Smith

    Rod Smith New Member

    Thanks to all that helped me out. I turned my first open segment bowl and everything went well using a combination of the different pieces of advise. Have any of you found a way to put a name of the plan on the Summary print and Row Print? It would also be nice to be able to print the Bowl View.
     
  11. Bob Beaupre

    Bob Beaupre Administrator Staff Member

    Rod you can export the bowl view to a jpeg image file and then print it out
     
  12. Lloyd Johnson

    Lloyd Johnson Administrator Staff Member

    Rod,

    You can also export the Summary to Excel and then add a title and format the document however you like. Go to the forum category ‘Follow Along Projects’ and watch Part 1 of the Open Segment Christmas Ornament where you’ll see how I use Excel to optimize and format the printout.

    I could not give you options anywhere near what you can get from Excel. Because Excel is so powerful and it is so easy to export the data to Excel, I won’t be adding much to the program.
     

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