End grain hollow form.

Discussion in 'Segmented Turnings Forum' started by David Creed, Oct 25, 2016.

  1. David Creed

    David Creed New Member

    Hi Guys, i have an old oak table top which was discarded as it has a bow, my idea is to saw off lengths of end grain and then segment as usual, in theory the glue up should be stronger as its all long grain, still havent decided on a shape but it should be interesting which is part of the fun, cheers Dave
     
  2. Lloyd Johnson

    Lloyd Johnson Administrator Staff Member

    Just a rule of thumb, Dave, and please don't ask why I know this...

    The grain on a segmented vessel needs to run around the bowl. This is somewhat counter-intuitive since a segmented ring does not have a lot of strength because the individual segments will be more than 50% end grain glued to more than 50% end grain. The strength comes from gluing these rings together because the glue joint between the rings is pure flat grain glued to pure flat grain. That is why over time, you could see delamination between segments due to changes in humidity, but never between the rings themselves.

    This is also why vertical spacers between segments should be made by cross cutting boards instead of ripping them to make the spacers. Cross-cutting means that the grain of the vertical spacers will also be oriented around the bowl which is much better than having a ring where every other component has the grain running in alternate directions.

    A stave cylinder or compound stave ring for a segmented vessel, on the other hand, is a very strong segmented ring because the joints between the segments are flat grain to flat grain. The problem comes when gluing this stave ring to standard segmented rings because there will be end grain of the stave ring to flat grain of standard segmented rings - an unreliable joint.
     
  3. Glenn McCarron

    Glenn McCarron PRO Member

    Is there a reason why you want to cut end grain strips versus ripping long grain strips? Much nicer turning when your not encountering end grain.
     
  4. Lloyd Johnson

    Lloyd Johnson Administrator Staff Member

    A graphic would help but I don't have the time right now. If you cut vertical spacers by cross-cutting a board and then standing those strips up on end means that you will NOT be turning vertical grain (it won't ever be end grain) because the grain will be horizontal and wrapping around the bowl like the other segments.

    When applying vertical spacers between segments, it is simpler not to do this and that results in the grain in those strips being applied vertical instead of horizontal and while I don't think your bowl will much lose strength over this, it will stick out like a sore thumb and will be roundly criticized by turners who don't do this.

    Don't ask me how I know.
     
  5. mfisher

    mfisher Super Moderator Staff Member

    I agree with you Lloyd regarding how to cut spacers.
     
  6. David Creed

    David Creed New Member

    Thats a bummer Lloyd, but at least i didnt waste time and oak on an unsound idea, thank you for that. One of the reasons i thought about this idea is that, here in the UK you can buy kitchen/counter tops made from pieces of solid wood with random grain patterns, i found a 4 1/2" strip in a bin some time ago and made 2 pot belly bud vases, see pic, i have never heard of one of these laminated tops come apart but fully take on board what you have said, cheers Dave
     

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  7. Lloyd Johnson

    Lloyd Johnson Administrator Staff Member

    David,

    To be sure, I use reclaimed or throw-away wood at every chance I get. One of my favorite destinations in Portland is Gilmer Wood Company (http://gilmerwood.com) which is one of the largest importers of wood products in the U.S. They have barrels of exotic woods that are perfect for segmenting if you don't mind doing the prep work yourself. You just have to keep the grain orientation in mind when you cut it into segments and just remember the most important thing - the grain should run around the bowl unless it is a stave construction.

    I also frequent a company that makes stair treads for high-end homes. They are sanded to 1" thick and come in exotics as well as common hardwoods. I have them set aside factory seconds for me and I usually take everything I can get.

    Since I don't have a lot of time available to spend in the shop, I like to make open-segment projects because they are fast and have extensive design capabilities. For these projects, I almost always buy the wood from one of several eBay vendors that precision sand their products to consistent thicknesses. They always have maple, walnut, cherry and a couple staples but you can almost always find some exotics as well. They are usually about 3" x 16" in 1/4" or 3/8" and they ship in Priority Mail boxes that arrive in 2-3 days. I keep stacks of this wood near my table saw so I can grab one as needed without having to thickness sand or do any preparation at all. Since they are mostly Central to East Coast varieties, the grain color is quite consistent. Search eBay for 'thin lumber' and you'll find them quickly. I'm not sure they ship to the UK, but your local eBay certainly will have something like this.

    The best news is that it is far less expensive than anything you can get at a retail outlet.
     
  8. William Prickett

    William Prickett PRO Member

    so correct me if I am wrong but what I read was....... when cutting spacers the grain should be running vertical up and down and segments horizontal around the bowl it this correct. :) just reading and gathering information in my brain :)
     
  9. Lloyd Johnson

    Lloyd Johnson Administrator Staff Member

    Bill,

    No. The grain of all segments, whether standard segments or vertical spacers, should be horizontal - running around the bowl.
     
    William Prickett likes this.
  10. William Prickett

    William Prickett PRO Member

    I have seen many many many people on youtube do it wrong and I was wondering but never said anything in fear that I may be wrong :)
     

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