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  • Square to round

    Hello fellow wood turners. I made a trip into Halifax Speciality Hard Woods this week and came home with a bunch of square bowl blanks.

    I did the normal things, made a flat surface on one side, drew two lines corner to corner to get the center, then struck a circle using a compass. Normally, most then head for the band saw to cut out the circle to help speed things up. Well it sucks to me be as I do not have a bandsaw and cannot afford a new one just now.

    I have experimented with jigs on my radial arm saw to do multiple cuts to make it near round, but at some angles, hard wood is not the easiest thing to cut even with a new or sharp blade. In the old days, I just cut the corners off at 45 degrees to make the blank 8 sided, threw a faceplate on it, then turned it to round. A slow process cutting all that scrap off not to mention the risk of catches and tear outs. I even experimented using my router to do that first cut or to but that did not work out so well.

    Guess my question is: How do those that don't have band sawas do it? I have never tried my hand held jig saw, but I cannot see that being a pleasureable experiance.

    Thanks for any suggestions

    Steve
    Steve from Chester NS

  • #2

    Re: Square to round

    Re: Square to round

    a bandsaw certainly is the best way of course

    a jig saw or recip(sawzall) saw will work but slowly, clamp the workpiece securely, saw away, moving the workpiece as needed. remember you are basically doing a rip cut rather than a crosscut(saw blade will be with the grain)
    my shop is a beaver lodge
    steve, sarnia, ont

    sigpic

    1940's Beaver Jointer

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    • #3

      Re: Square to round

      Re: Square to round

      I have a fairly big lathe, a 20" General 260, and I often don't bother trying to round the blank very well at all. No argument about the rounder it is being smoother but it takes some time to do it and if you don't have a bandsaw then it is even more difficult which is the subject of your post.

      A lot of the tearing and bumping due to an unround blank can be eliminated by roughing the correct way. In case you aren't doing it this way, do not stick the tool into the bumps at 90 degrees to the bed. Start at the centre near the tailstock if you are using it and then cut outwards to the bowl rim. You will be cutting some air near the edge but it is mild compared to trying to cut the bumps. As you shape the bowl bottom you will automatically be rounding the blank.

      Knocking off the corners by any amount before you start is a big help,

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      • #4

        Re: Square to round

        Re: Square to round

        1+ on what Bill said.
        I normally just knock off the corners with a chain saw.
        Since you will be getting a lot of bumps it helps to raise the tool handle if you are starting at about 45* down. Raise it about halfway and a lot more of the force of the cut will be put into the tool rest rather than shoving the handle back. Once you have it rounded you can drop the tool handle again.
        I set the rest at 45* to the bed and just start at the corner taking about 1/8-1/4" bites sliding the tool across. Keep the rest close and it doesn't take very long.
        I do have a bandsaw but have never used it on a blank. I agree with Jamieson that it probably takes longer to round it on the bandsaw than on the lathe, but you can start the lathe faster if rounded on a BS.
        Between two evils, I always pick the one I never tried before.

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        • #5

          Re: Square to round

          Re: Square to round

          Good day all. Thanks for all of the replies to my question. Made up some more blanks today. Used the chop saw instead of the radial arm saw. Made very quick work of getting it close to round.

          Sat the miter at 45, lined up the cut to the circle I had drawn, set a stop block and then cut the 4 corners off. Reset the miter to 22 1/2 degrees and knocked off the 8 corners left by the 45 degree cuts. Now being 16 sided, the outside turned very quickly to round. A couple of quick cuts on the lathe, and I am good to go. Had to stop turning so I could clean up a bit, 2 jumbo sized garbage bags of shavings. Saving then to use as kindling for the wood furnace, or mix then with paper and water and press them into logs.

          Anyway, back to the shop, nice and cool in the basement of my house compared to the 31 degrees outside.

          Pictures soon

          Steve
          Steve from Chester NS

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          • #6

            Re: Square to round

            Re: Square to round

            Just for fun, try leaving some square and turning it so you end up with square plate.
            People who start with burls and other rough pieces don't make any effort to make it round, but your process is as good as any.
            In an age when scientists are creating artificial intelligence, too many of our educational institutions seem to be creating artificial stupidity. - Thomas Sowell

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            • #7

              Re: Square to round

              Re: Square to round

              Hey Steve, I didn't hear anything about a chainsaw but if your shop is in the basement then you don't want to run it there so get an electric you can get them as low as 80.00 bucks, cheaper then a bandsaw. If you are like me you get a bandsaw and then right away want a bigger one, it never ends. HAHAHA
              Darren in Oshawa

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              • #8

                Re: Square to round

                Re: Square to round

                Hi Steve

                Hope you didn't spend all your pennies on the blanks

                Unless you can use the small corner cut-offs, I would just turn them away, if you turn from the center out and up/around to the top of the blank this works pretty good, this picture shows it a bit, as you can see the cut after cut that has been made to the top of the blank.

                Rouging blank.jpg

                Of course as was mentioned you don't have to make every blank round, turning pieces that are not round but rectangular or square, just a few pictures here to show some that I have done, should get you some ideas if you want to go that way

                Japanese Lilac.jpg Black Cherry.jpg Black Walnut.jpg Walnut bowl.jpg
                sigpic
                Have fun and take care
                Leo Van Der Loo

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                • #9

                  Re: Square to round

                  Re: Square to round

                  Thanks for the additional comments.
                  Gene: I have turned them from square in the past. Takes way too much time and restarting evertime you move the tool rest in closer. I have made a few square bowls. In a few days, as soon as I get the pictures ready, you will see a six sided tray that I made a week ago.
                  Thenewguy: Chainsaw and wood lathe, sounds too lethal to me. Would be ok if the blanks were 15 or 16 inches across, but I am talking less that ten inches, mostly 5-6 inch.
                  Leo: Some great suggestions in your work there. I wil lattempt one like this as sson as I get cleaned up and ready for the show this weekend.

                  Thanks all
                  Last edited by Steve McCarron; 08-14-2012, 01:40 PM. Reason: Typo
                  Steve from Chester NS

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                  • #10

                    Re: Square to round

                    Re: Square to round

                    Originally posted by Steve McCarron View Post
                    Thanks for the additional comments.

                    Thenewguy: Chainsaw and wood lathe, sounds too lethal to me.

                    Thanks all

                    Clamp the blank down to cut it, I wouldn't dare try the chainsaw on a running lathe. Nor would most of us.
                    In an age when scientists are creating artificial intelligence, too many of our educational institutions seem to be creating artificial stupidity. - Thomas Sowell

                    Comment


                    • #11

                      Re: Square to round

                      Re: Square to round

                      My bandsaw isn't powerful enough for thick hardwood. I also use the miter saw technique. 45 the corners and then setting it to 22.5 degrees has worked great for me. I have also tried just turning the blank with 8 sides but it takes a lot longer.

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