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how to hollow segmented pieces

Discussion in 'Woodturning Discussion Forum' started by Don C Davis, Jul 21, 2020.

  1. Don C Davis

    Don C Davis

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    I have been building some segmented vases etc. and It is really slow going 'hollowing' the inside of these. I typically use a carbide finisher--round tip--carbide tool. Alternatively I use a bowl gouge and start smoothing/hollowing the inside once I have 3 rings glued on top of each other--I'm looking for advice insight on how to be efficient at hollowing/smoothing the inside wall of these segmented pieces--

    Any advice/input is appreciated!
     
  2. Doug Freeman

    Doug Freeman

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    There are 2 approaches to segmented pc hollowing - glue it all up and then hollow it, or hollow piecemeal as you describe. This can be done with a lot of variations - any number of rings at a time. I’ve glued up top and bottom 1/2’s, hollowed the bottom, glued the top on, then finished it. Hollowing deeper than 3-4” by hand held gets challenging. Captive or articulating systems remove a lot of the project and personal injury risk inherent in hand held hollowing.
     
  3. Roger Wiegand

    Roger Wiegand

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    I haven't done any segmented hollow form turning, but it would seem that you'd want to do the entire glue-up prior to shaping. Two major issues occur to me, one is that it would be really hard to make a smooth, flowing continuous curve a little bit at a time and two, if you thin out the base that is supporting the work first you're going to have a lot of vibration as you get farther out. Most times one thins the outermost edge first and then works back toward the tailstock.
     
  4. Don C Davis

    Don C Davis

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    Interesting input fella’s—I still am not sure what the best tool to use is!!
     
  5. Don Wattenhofer

    Don Wattenhofer

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    My approach to segmented hollow forms is a little different then most since I tend to glue up stacked rings or staved, then put them aside until I think of a use for them.
    The staved type are no different then a solid wood hollow form meaning that it is mostly side grain that is being removed, reference my avatar.
    The stacked rings are easier to get a smooth surface because the cut is basically linear to the wood grain.
    I have an articulated hollowing system that I don't use any more because I feel that it is to cumbersome so I have gone back to my arm brace or my selection of ring, proform and bured scrappers mounted on big heavy 4' long steel shafts.
    Note: I do not understand what is dangerous about free hand hollowing unless you are over extending for the capabilities of a particular tool.
     
  6. Russ Braun

    Russ Braun

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    I am a segmenter. Any vessel with depth, like a vase, is glued up in sections (1-3 sections).

    If I use two sections (halves), the segments are glued directly to waste blocks on separate faceplates. One half has the bottom ring is glued to the bottom waste block, stacking rings towards the center of the vessel. The other half starts with the top ring glued to the waste block working toward the center.

    As I stack rings, I true and flatten them only keeping maximum thickness. Once halves are stacked, glued and trued, I put them together “dryfit” between centers including waste blocks and faceplates.

    I turn the outside form to where I want it. I then separate the halves again and turn the inside of each to matching wall thickness using calipers to maintain uniform thickness. The halves are sanded and finished on the inside. The two halves are then glued together using masking tape to keep Glue squeeze out contained on the interior.

    Once dry, I remove the top waste block giving me access to the inside of the vessel. Typically, a little touch up is required along the glue joint only on the inside. I then finish the outside, part it off the bottom waste block, finish the bottom to complete.

    Doing three or more sections complicates matters but is basically the same drill. This is the easiest way to turn, and finish deeper segmented vessels IMO.

    I highly recommend getting Malcolm Tibbett’s first book on Segmenting (one of several). His basic techniques are tried and true; what I do is gleamed from his developed techniques. He deserves mentioning as he is one of my Gurus and a huge innovator in the world of Segmenting!

    There is also an AAW group dedicated to Segmenting - Segmentedwoodturners.org that will help you hone your segmenting skills. It has a huge library of pieces, tutorials and a membership always willing to answer your questions! Check it out for a free trial!
     
  7. Don C Davis

    Don C Davis

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    Russ Braun, thanks for the input, your approach seems very practical to me--I don't currently use wasted blocks but that may be a way to eliminate some of the issues that are bothering me.
     
  8. Robert D Evans

    Robert D Evans

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    I do mine similar to the way Russ explained. The picture shows a vase that has threaded glue blocks on each end. I held them together with tailstock pressure and turned the outside. Then separated them and finished up the inside, glued the two halves together on the lathe. When the glue is dry I cleaned up the outside glue joint, sanded and parted off the tailstock glue block. I made my glue blocks with a Bealle tap and maple scraps. I can use the glue blocks for several projects if I'm careful about parting off.

    IMG_2544.JPG
     
    Russ Braun likes this.
  9. Don C Davis

    Don C Davis

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    Heck Robert, I feel like a schmuck when I see pics of work like yours! I’m still thinking I am doing something alternating species side by side in my rings—figuring out a good way to ‘hollow/smooth’ the inside of a piece must sound very’Newbie’ to you.
    Thanks for the input sir I really appreciate it.
     
  10. Robert D Evans

    Robert D Evans

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    Hey Don,
    It's not that hard once you get started. I taught myself how to do this earlier this year. Since the pandemic, I've had lots of time on my hands and youtube is a great resource. As it turns out, I already had most of the tools I needed in the shop.
     
  11. Robert D Evans

    Robert D Evans

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    These are some of my segmented projects I've made since March. The vase on the far left is the one that was pictured on the lathe. IMG_2505.JPG IMG_2592.JPG
     
  12. Don C Davis

    Don C Davis

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    Man those are beautiful pieces brother, I have a lot to learn--Great work man!
     
  13. Mike Johnson

    Mike Johnson

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    Very nice indeed, all of them are show quality pieces!
     
  14. Don Wattenhofer

    Don Wattenhofer

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    I totally agree and I have done many deep segmented hollow forms.
     
  15. Russ Braun

    Russ Braun

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    I know many segmenters that thread their own waste/glue blocks instead of using faceplates! I might have done the same if I had heard that idea prior to investing in a 1/2 dozen faceplates! Nice work Robert!
     
  16. Russ Braun

    Russ Braun

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    I’m in the middle of a 25K plus piece glue up Don. I am doing it as a follow along project on the segmentedwoodturners.org site. You will soon see how I turn/ finish each of my three sections after creating my outside form with them joined together dry-fit. You should fully grasp the concept once seen; if not, I am here for you Brother!
     
  17. Mike Adams

    Mike Adams

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    I've watched a few large segmented vessels being turned. David Marks and Kyle Toth both have assembled some _large_ segmented pieces and both hollowed in sections. With smaller projects, I see a mix that seems dependent on the vessel's diameter and opening, and the turner's comfort level.

    The turnings I've seen done in sections were all somewhat wide all had small openings
     

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