Bunmawashi (Japanese Beam Compass)

2018-08-20T17-39-21
Later I have been doing some volunteering work at a neighbourhood tools library and wood shop; several users there have asked me if we had anything to draw a circle, so I decided to make a simple beam compass using bolts and wing nuts to hold the pencil and tighten the mortise around the beam (the nail sticking out of the upright sank between the workbench top boards in the photo) #BeamCompass #HandToolsOnly #AmericanElm #Elm #WhiteAsh #Ash #Woodworking
2018-08-21T16-47-28
Making the beam compass for la Remise inspired me to make one for myself too; after a little browsing, I decided to make a Bunmawashi, a Japanese beam compass, as presented by Toshio Odate, but adapted to hold a pencil. Still work in progress, but it should not take much longer to finish it. I am using Butternut for the beam and post and Black Walnut for the wedges. BTW, planing Butternut is sheer fun! #Bunmawashi #BeamCompass #HandTool #HandToolsOnly #Butternut #BlackWalnut #Walnut #Woodworking
2018-08-22T15-14-27
The vertical post of the bunmawashi has an octagonal section; I started by tapering four sides; hammer and chisel and block plane for the bottom part and Jack plane for the top part. For the remaining four sides, I had some trouble holding the piece so I built Jim Tolpin's sticking board for dowels; this worked very well for the first few passes with the block plane and once those sides got large enough (or too large for the sticking board) I finished off holding the piece on the bench. The final result is not a perfect octagon (I had some trouble balancing the block plane perfectly flat, especially on the bottom part), but is respectable enough. #Bunmawashi #BeamCompass #HandTool #HandToolsOnly #Butternut #BlackWalnut #Walnut #Woodworking
2018-08-23T08-00-17
The Bunmawashi is ready for service; it can draw circles up to 60" in diameter. This short, immediate gratification, project was real fun to work on. #Bunmawashi #BeamCompass #HandTool #HandToolsOnly #Butternut #BlackWalnut #Walnut #Woodworking

2018-08-23T08-04-29
The Bunmawashi is ready for service; it can draw circles up to 60" in diameter. This short, immediate gratification, project was real fun to work on. #Bunmawashi #BeamCompass #HandTool #HandToolsOnly #Butternut #BlackWalnut #Walnut #Woodworking

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