Turning Squares into Triangles
Turning Squares into Triangles By Bill Turpin This is a report of a demo by Nicholas Di Mona at the 2012 Florida Woodturning Symposium. You start with a cube of hardwood of 2.5” or larger. Smaller wood is possible, but extremely difficult to work. Cube edges should be sharp and precise. You will need a live tail-stock center with a removable point (Oneway or similar) and a homemade jig. Hold the jig in any chuck and remove the point from the live center. Place the cube with one corner in the hole left by the removed point and the opposite corner in the wooden jig.
Dremel grooves actually provide the turning force. They must be accurate and true. Grooves are both 1/4” wide and deep. Dimensions of jig are adjustable. However the 120° are not. Chamfer the groove edges with a knife. Using a sturdy parting tool, cut between the spinning ghosts “A” and “B”. Cut about one quarter into the cube. Gradually curve the cut towards lathe ends, deepen, and widen the cut. Cut a shallow tenon on the tailstock end, and prep the cube corner inserted in the tailstock for removal. Shape the tenon end so that you have triangular wings (curved down towards the tenon end) of a balanced thickness. If you BREAK a wing off, remove all three. Remove from the lathe and remove the tenon stub. Remove the jig from the chuck, reverse the workpiece, and put the tenon in the chuck. Cut a curve in the top triangular wings. Demo was completed as a box. Drill thru the top wings into the body. Use standard box procedures for a lid that inserts into the box. Useful for small objects like a grandchild’s first tooth, a single ring, etc. Sand, finish, and remove the tenon. The wing sets will be at 120° to one another. The original cube
needs to be fairly exact. You start with eight corners, turn two of them off, and you end up with two triangle curved dishes with a box in the middle. Please excuse my poor computer drawing skills.
Rotate the second image 90° clockwise for the orientation on the lathe while tenon is in the chuck. Triangle tips should curve more towards the finial and base than my picture shows. Star image is view from above the finished box. As the size of cube is increased, make the diameter of the 5/8” hole larger and increase the depth of taper in the face of the jig. Demo used burl for the body, blackwood for the lid, and a lighter colored finial. A lot of hand sanding is required. You will be sanding side grain, cross grain, middle grain, end grain and probably tear out.
.
Dremel grooves actually provide the turning force. They must be accurate and true. Grooves are both 1/4” wide and deep. Dimensions of jig are adjustable. However the 120° are not. Chamfer the groove edges with a knife. Using a sturdy parting tool, cut between the spinning ghosts “A” and “B”. Cut about one quarter into the cube. Gradually curve the cut towards lathe ends, deepen, and widen the cut. Cut a shallow tenon on the tailstock end, and prep the cube corner inserted in the tailstock for removal. Shape the tenon end so that you have triangular wings (curved down towards the tenon end) of a balanced thickness. If you BREAK a wing off, remove all three. Remove from the lathe and remove the tenon stub. Remove the jig from the chuck, reverse the workpiece, and put the tenon in the chuck. Cut a curve in the top triangular wings. Demo was completed as a box. Drill thru the top wings into the body. Use standard box procedures for a lid that inserts into the box. Useful for small objects like a grandchild’s first tooth, a single ring, etc. Sand, finish, and remove the tenon. The wing sets will be at 120° to one another. The original cube
needs to be fairly exact. You start with eight corners, turn two of them off, and you end up with two triangle curved dishes with a box in the middle. Please excuse my poor computer drawing skills.
Rotate the second image 90° clockwise for the orientation on the lathe while tenon is in the chuck. Triangle tips should curve more towards the finial and base than my picture shows. Star image is view from above the finished box. As the size of cube is increased, make the diameter of the 5/8” hole larger and increase the depth of taper in the face of the jig. Demo used burl for the body, blackwood for the lid, and a lighter colored finial. A lot of hand sanding is required. You will be sanding side grain, cross grain, middle grain, end grain and probably tear out.
.
