How to cut an exact round shape by hand?
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- This topic has 10 replies, 8 voices, and was last updated 6 years, 10 months ago by Philipp J..
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20 April 2017 at 9:55 pm #311338
Look at pauls instructional video on making a 3 legged stool. he goes through the process of turning a square board into a round seat
22 April 2017 at 1:26 pm #311362You always start with a precise line. Then use a coping saw to cut a bit over size, refine with chisel, spokeshave, rasp, file, scraper or sandpaper. The closer you get to the line, the finer your tool. And always pay attention to the grain direction.
Dieter
Amusingly, there is a saw called a “table saw” (and I don’t mean the machine) which was precisely for cutting round table tops
just saw one in a video on Youtube a coupla days ago: https://youtu.be/i0WmSUfZVWg?t=2m48s
26 April 2017 at 10:12 pm #311444I think, even with these saws, you still need to refine the cut. But they should work well, somewhat like a manual band saw. I have seen some on flea markets for quite cheap, but usually well rusted and horribly bent…
Dieter
Just saw this, and I think this would be the best answer, for me at least. Sure, you’ll still scribe an accurate circle and rough out most of the waste with saws, but once you’re down to a coupla mm left, and want to finish perfectly, I might go this way:
http://www.jimbodetools.com/images/products/390884.jpg
A fenced compass plane. The radius will be built into the plane, so it’ll be perfect, and the fence will keep you dead square. Make whichever size you require, and it’d be hard to beat.
22 May 2017 at 12:52 pm #312165Hi!
This is quite extensively explained for boat-building masts and spars, have a look at: http://www.boat-building.org/learn-skills/index.php/en/wood/making-wooden-spars/
The instructions show the use of a ‘spar gauge’ which is explained in more detail here: http://www.pettigrews.org.uk/lm/page030a.htm
Hope this helps..
13 June 2017 at 6:43 pm #312922Been meaning to try something that may achieve this – draw a circle the size you want with a giant compass (a piece of wood with a nail through for the centre point and a hole in the other end with a pencil sticking through. Then using the arc of the circle, cut out a curved piece of wood a few inches “long.” Then you could screw in a piece of bandsaw blade to the wooden arc, attach the wooden arc to the end of the wooden compass and use it as a sort of curved kerfing plane. If it works it may be quicker than handsawing past the line of a drawn circle and then refining with files / spokeshaves etc. Especially if you reuse the jig.
13 June 2017 at 7:56 pm #312924That might work Josh however i think you may get a problem with the saw getting clogged up, constantly, theres nowhere for the chips and sawdust to go. Thats probalbly why Coopers used the rounded planes instead of a saw like you describe.
Something that might work is, if you drill a center hole and mount the rough sawn blank on a peg or something so it can spin you could clamp a plane on its side to your benchtop and turn the blank towards it.
Slowly advancing the plane closer should ultimately give you a perfect circle in theory, if it actually works or not would require a trial run, but its a thought. -
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