Turning laburnum (Golden Chain) - my most gnarly starting block

Discussion in 'Newbie' started by Jamie Straw, Mar 24, 2016.

  1. Jamie Straw

    Jamie Straw

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    Just want some company on this journey. I've had a 4' long Laburnum log floating around for 5 or 6 years now, came down in our back yard and I got hubby to cut the trunk to size, sealed the ends and have just shuttled it from one place to another in the wood pile all these years. Finally cut it into blanks two weeks ago, and put the first one on the lathe today. The flat spot just the other side of the tailstock is where I cut off a burl with golf-club-shaped birdseye in it, which I'm hoping a pen turner might be able to use. I'm hoping the next bowl will be natural edge, to take advantage of the striking black edge on these pieces. The heartwood is dark chocolate brown, other tones run from a yellow-cast to the black, and that pinkish layer in between. Common name is Golden Chain Tree.

    As first mounted on lathe:
    Laburnum 1AAW.jpg


    After a little work -- having figured out what speed I could go at. Started at level 1, then 2, hard to turn air at #2. As soon as I could, I went to 3. Then had to come in for dinner.:D Back to it in a little while.
    Laburnum2AAW.jpg
     
    Last edited: Mar 24, 2016
  2. odie

    odie

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    Jamie......

    Is that black streak part of the bark, or is it part of the sap wood? If that color can be kept, it would make an interesting contrasting color.......
     
  3. robo hippy

    robo hippy

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    I know the Brits love it. I have a few pieces, and it is all darker than that. I have heard that just about every thing on the tree is toxic also. Never checked that out though.

    robo hippy
     
  4. Jamie Straw

    Jamie Straw

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    I think, looking at this diagram, that it's the phloem (inner bark), and the pinkish layer is the cambium. Yep, I want to get a natural edge out of what I have left.
     
  5. Jamie Straw

    Jamie Straw

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    The toxic nature...

    Yes, it is considered toxic, most problematic incidents seem to come from people (kids, mostly) eating the seed pods or, occasionally, the leaves. Contains cytisine, symptoms similar to nicotine poisoning, but evidently not as poisonous as nicotine. Here's the best article I found on it: http://www.thepoisongarden.co.uk/atoz/laburnum_anagyroides.htm I'm wearing dust mask and long sleeves, but not worrying about wearing gloves for turning. Probably will for sanding, just because I easily react to sanding dust of many kinds.
     
  6. Jamie Straw

    Jamie Straw

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    Ahhhh, geez, not a great day...

    Man, this stuff is dense and hard. Am sharpening 3x as often as usual. Then there's the fact that I didn't wrap it up last night so some little checks were there today, been tap-dancing around them all afternoon. [Again learning that "dry" doesn't mean much.:p] Worst thing, though, is the fact that when I turned it around to hollow it (going from between centers to in the chuck), it didn't run true so I'm having to (try to) reshape the outside. For homework, I will make a list of what could have caused that. "Thanks for listening" says me.:)
     
  7. odie

    odie

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    Well.....I also had one of "those days" today! :mad:

    I guess we all have them...... :rolleyes:

    One thing to take into consideration, is every piece of wood is an "individual"......sometimes those from the same tree don't respond to tools exactly the same.

    I've found that some wet blanks can dull tools really fast.....even more so than dry wood......Well, there is that occasional dry piece of wood that can be a bugger, too! ;)

    Tomorrow is a new day.....I won't mess it up by thinking too hard about today!:p

    ko
     
  8. Bill Boehme

    Bill Boehme Administrator Staff Member

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    I'll help you start the list:


    • Just because the chuck body runs perfectly true doesn't mean that the jaws will have the same center as the body. In fact, it would be very surprising if they did. The reason is that machining tolerances for the scroll, the base jaws, and top jaws, all stack up to ensure that there will always be some error.
    • When the jaws are tightened on a tenon (or recess), the wood fibers don't compress equally all the way around because the grain orientation varies from side grain to end grain. Also, various grain features affect the compressibility.
    • The simple act of removing something from the lathe and then remounting it will always result in some alignment shift even if using the same chuck.
     
    Last edited: Mar 28, 2016
  9. hockenbery

    hockenbery AAW Advisor Staff Member

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    If I'm turning a hollow forms or a bowl once I finish turn the outside after it is mounted in the chuck or on a faceplate.
    For a thin walled turning I want it dead center so I just do that last surfacing when mounted for hollowing.

    For a rough out a little off center is no big deal.

    If a piece is running a little untrue it can often be corrected by loosening the Chuck and moving the piece toward true an tightening it.

    When it is off a lot it is usually the tenon: a little long, match to the jaws profile is off. torn grain on the tenon or when the tops of the jaws rest, torn grain or fuzz in the corner of the tenon.

    I prefer using a spindle gouge to cut the tenon walls because I get a clean surfaces and a clean corner.
    Scrapers and parting tools often leave a rough surface especially if they are not sharp..

    Al
     
  10. odie

    odie

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    There is a philosophy in coaching sports, that if a good player screws up badly.......don't take him out of the game. Instead, give him responsibility by keeping him active in the course of the game. That is a philosophy we can apply to ourselves. The thought behind this is a good player will dwell on his mistakes, and that becomes a psychological negative. It's better for our mental outlook to rebound with our successes.....than to dwell on our failures.

    After screwing up pretty badly the other day, I took out one of my best "promising" roughed bowls and worked on that in a marathon session yesterday.......and, now I am looking back at "accomplishment" again!

    This is good for the soul......:D

    ko
     
  11. Jamie Straw

    Jamie Straw

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    The tenon was a little long, I sanded it down on the belt sander to make it clear the bottom of the chuck. My jaws are right-angle (not dovetailed), but I suspect some other little thing was a bit off. It was off enough that I could feel it, but didn't really see it when it was spinning.
    Yep, I used my spindle gouge for finishing off the tenons.
     
  12. Jamie Straw

    Jamie Straw

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    That piece of Laburnum was just full of lessons.:p I didn't cut far enough away from the pith, it started a little crack right after I rough-turned it. I also got what appear to be heat checks, embarrassingly I suspect those were from tool heat. I finished the bowl as a "thick" specimen, with a recessed base, and went ahead and sanded it followed by Watco. I immediately took another piece of Laburnum and slapped it on the lathe. Sharpened the bowl gouge, ground the heel back more than it had been, and went to work again. It started developing cracks too, but my tool technique improved, with no burnishing or heat checks. It started to crack near where the pith had been removed, so I sacrificed it (cut in half). Today, I pulled out the moisture meter and checked the level in the other pieces I have from that tree. They weren't near as consistent as I had thought, so I cut them well away from the pith, cut to reveal fresh end grain, and Anchorsealed. Will let them sit for awhile before attempting any more bowls. Don't want to waste what's left, 'cause don't know when another tree that size will come along.:eek:
    Laburnum Bowl1.jpg
     
    Last edited: Mar 28, 2016
  13. Jamie Straw

    Jamie Straw

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    Update

    Had a session with my mentor today, and he looked over the little bowl. Reassured me that the check I thought me due to heat were not. Just the wood being wood.:)
     

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