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Thread: Sphere projects photos

  1. #1
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    Sphere projects photos

    Dave Mount did a great job of detailing how he turns spheres. I can not be the only one who tried it. Let's all express our appreciation for Dave's efforts by posting photos of our sphere like round things.

    Mine is a 3 inch American Elm sorta round ball.

    Elm Sphere.jpg

    I used Dave's method to get to the 3D octagon, Rounded off the corners and remounted it to turn the extra wood where it had been mounted. Then I sort of fell into my old habit of just remounting it in many orientations until it looked and felt right. The grain in the original blank ran approximately 20 degrees from the axis, so I really paid little attention to how I was mounting it each time.

    In the past I used a method that was posted on the creek several years ago. Turn a cylinder and rough out a sphere staying a little greater than the diameter of your cylinder. Then remount with the original axis vertical and use a parting tool to cut a groove through the middle of your sphere until it just touches the cylinder diameter which is now the horizontal centerline. You now have two circles at 90 degrees to each other that clearly mark out the wood that you need to turn away. I think Dave's method was more accurate and if you are trying for a sphere with a defined diameter much more likely to be successful. Once you get to the octagon for a 3 inch sphere there is really very little wood left to remove and very little chance of making a mistake with Dave's method.

    Looking forward to seeing your spheres, balls, or sorta round things.

  2. #2
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    I will admit to making mistakes when I measure things. Over the years I have developed habits that eliminate measurements. I was going to include this in my first post as part of how I differed from Dave Mount's process, but it gets a little long and might not be of interest to many. So here is how you don't do any measuring while using Dave's method of making a sphere. I have seen versions of this posted elsewhere. They always include a drawing that is really not necessary as you can easily make your own chart.

    This is much easier to use if you do it on graph paper. Start by drawing a vertical and horizontal axis that intersect near the bottom left corner of your page. On the horizontal axis mark the diameter of the largest sphere you are likely to turn. Now draw a line from the top of the vertical line to the mark you made on the horizontal axis. Next mark 0.293 inches from the intersection of the two axis and draw a line from the top of the vertical line to this new mark. Take this chart to your shop.

    Turn the cylinder and mark the ends following Dave's directions. Set your calipers to the diameter of the cylinder on the actual cylinder. Lay the calipers on the chart parallel to the horizontal axis with one tip on the vertical axis and the other on the line representing your diameter. (This is where you wish you had used graph paper.) Draw a horizontal line between those two points. Now reset your calipers so the points are on the vertical axis and the line that you drew 0.293 times your largest sphere diameter while on the horizontal line you just drew. Take them to the lathe and mark the distance from each corner as Dave explained in his procedure.

    When I made my chart I did it on an extra long piece of paper. After laying out the lines I cut the top off so that a 1 1/2 inch diameter was near the top of a standard sheet of paper and a 6 inch diameter was on the horizontal axis. After using it a few times I realized the need for graph paper to help keep the calipers horizontal when setting the 0.293 times the diameter measurement.

    If you think you might want to try the 16 sided rough out you can draw another line on the same chart. I used distance from each corner along the facet with is 0.108 times the diameter. Note in Dave's procedure he used the length of each facet and then eyeballed the middle. That distance is 0.199 times the diameter. Lay out another line for the method you choose the same way you made the first line. I tried the 16 sides using the distance from each corner along the facet and it was worthless on a small sphere. If I ever make a really large sphere I will use Dave's length of the facets measurement of 0.199D.

  3. #3
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    Nice sphere! You can say all you want about it not being truly round, but the picture sure doesn't betray it if it's even true -- I suspect its "spherocity" is proportional to your modesty (both substantial).

    I like the elm, especially the "swoop" in the grain in the upper half of the photo. I've found that often the spherical shape displays the grain of the wood in ways that you wouldn't intuitively expect looking at the square blank.

    Your "no measurement" hack for layout is very clever. If I understood it right, it's something as in the photos below (correct me if I misunderstood). Since it's just a proportion and not a measure, the attached jpg can be rescaled to any size for printing as long as the photo proportions aren't changed. The same thing could be done for the 0.199*diameter step to the hexadecagon. That would allow accurate layout using nothing more than old fashioned outside calipers. Do it on a treadle lathe and you have a Roy Underhill approved sphere. . .

    Capture117.jpgCapture118.jpg

    Best,

    Dave

  4. #4
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    Your triangles work just as good, and might be easier to understand. Mine are a little different. Here is a photo of the one I used for the last 5 or 6 spheres. That makes it several years old. I find my place on the chart by matching the diameter of the cylinder horizontally from the vertical axis line to the line marked diameter. I draw a horizontal line at that point on the chart. Then I reset the calipers to the distance from the vertical axis to where the horizontal line crossed the line marked 0.293D.

    sphere chart.jpg

    It is interesting, or perhaps embarrassing, that despite a 53 year old engineering degree and more math education than I knew what to do with, I still printed the article I first read about this method and didn't think that it is just proportions and I could draw it anyway I wanted. Then when I drew my own I didn't tumble to the fact that it would be a lot easier to line up the horizontal line if you made your chart on graph paper. You can see on the chart why trying to do the corner to corner measurement for a 16 sided figure with a 3 inch diameter is a waste of time.

  5. #5
    Quote Originally Posted by Paul Williams View Post
    Dave Mount did a great job of detailing how he turns spheres. I can not be the only one who tried it. Let's all express our appreciation for Dave's efforts by posting photos of our sphere like round things.
    .
    Spheres with feet.....

  6. #6
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    Quote Originally Posted by Lawrence Duckworth View Post
    Spheres with feet.....
    How clever!
    Last edited by John K Jordan; 07-18-2021 at 6:00 PM. Reason: typo!

  7. #7
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    Quote Originally Posted by Lawrence Duckworth View Post
    Spheres with feet.....
    Very nice work, and as John says, very clever. Tell us about the inserts please. Glass? Resin you cast yourself?

  8. #8
    Quote Originally Posted by Robert Hayward View Post
    Very nice work, and as John says, very clever. Tell us about the inserts please. Glass? Resin you cast yourself?
    These inserts are boro glass marbles, Robert. I made a bunch of them awhile back after some surgery and couldn't be on my feet for any length of time. What's interesting to me is they're somehow magnified in the wood sphere; my granddaughters love 'em.


    Here's an expert link to how they're made.

    https://www.youtube.com/watch?v=Cj1Oy0W3CbE

  9. #9
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    Very interesting video. What diameter are the marbles?

  10. #10
    these Boro marbles are 1.75 to 1.85

    here are some furnace glass marbles, about 2.8" completely different glass and process, but still a sphere obsession

    CCECEDF9-FA9A-4167-88B2-7C887F9BB0C0.jpg

  11. #11
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    Quote Originally Posted by Lawrence Duckworth View Post
    these Boro marbles are 1.75 to 1.85

    here are some furnace glass marbles, about 2.8" completely different glass and process, but still a sphere obsession

    CCECEDF9-FA9A-4167-88B2-7C887F9BB0C0.jpg
    Very nice, and again, clever. Seems like a wonderful obsession!

    So I take it you're a glassblower/worker. Do you have a glass studio with a kiln or use one in a studio nearby?
    A daughter-in-law works in glass but hasn't had access to a kiln for years. A potter friend with 4 kilns has considered about making one for glassblowing - he has a 2" natural gas line to his house which should help.

    I've never experienced glasswork but I was mesmerized watching the glassworkers in Murano Italy. Some of the work displayed in glass shops and galleries was astounding.

    BTW, I once stumbled on a woodturning shop in Venice where the turner apparently liked to turn spheres and variations, eggs and such. Unfortunately the shop was closed at the time.

  12. #12
    I agree that the glass process is mesmerizing...and I've enjoyed it as a hobby for quite awhile....but woodturning is super addictive 7FD5EE7E-ED8F-4EF0-A456-FEFC5309AF66_1_201_a.jpeg 68B516C4-F859-4A8A-99CC-B8CAF56EE36F_1_201_a.jpg
    Last edited by Lawrence Duckworth; 07-19-2021 at 7:11 PM.

  13. #13

  14. #14
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    Quote Originally Posted by Lawrence Duckworth View Post
    Are these made at least partially from steel?

    JKJ

  15. #15
    Yes they’re steel. I pretty much quit messing with steel. Did it most of my life.

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