是的，你没有看错：trircle!我将向您展示如何制作独特形状的碗on a bandsaw with a really simple jig. Using the technique you can make oval, triangular, rounded rectangle, and rounded five-sided bowls. As an added benefit, you get more than one bowl each time and they will perfectly nest to make a complete set. I’ll describe the technique by making atrircle碗套；那是具有圆形三角形的碗。
I will show a lot of pictures. Take a look at them, they are annotated throughout for additional information!
Bandsaw, miter saw, sander
Various small pieces of wood.
步骤1：Fusion 360 Trircle的模型
Before we go into the workshop, let’s model these bowls inFusion 360。
Use the attached Fusion 360 file (triangular bowl parametric.f3d) to follow along for thetrircle。I made the design parametric so you can change the shape and size of the bowl; and get the relevant measurements for making it in your shop.
将Fusion 360文件加载在“设计工作区 - 实心”中，然后转到“修改”>“更改参数”。您应该在上面的第二张图中看到一个屏幕。
The shape of the bowl is determined by the radii of the two different arcs forming the sides.
You can change these two parameters: the large_arc and the small_arc
然后，碗的“直径” D由d = groun_arc + small_arc给出
If the values of the large_arc and the small_arc are close to each other the bowl shape approaches a circle. A good range for a pleasant looking trircle is for the small_arc to be somewhere between 10% and 50% of the large_arc. The example we are making below has the values of large_arc = 5.5 inches and small_arc = 1.7 inches, resulting in a 7.2 inches ‘diameter’ bowl - measured at the bottom. The top of course is larger because of the angled sides!
您可以在Fusion 360中更改大_arc和small_arc，并立即看到所得的碗形状。在“参数”窗口中，单击“大_arc”或“ small_arc”的“表达式”以更改其值。值以英寸为单位。下一步中的动画显示了一个trircle，对于Small_Arc参数，从0.4英寸到5.5英寸。
Step 2: More Model Parameters
(1) the angle of the sides of the bowls
(2) the height of the bowl sides
(3) the wall thickness of the sides
Keep the parameters at reasonable values otherwise the results become unpredictable or break the model.
The last parameter is calculated:
triangle_side =（大_arc -small_arc）
您将需要此测量来布置并切割自己的碗设计as described below. In our example triangle_side has a value of 3.8 inches (5.5" - 1.7" = 3.8").
Once you have a design that you like write down the values for triangle_side, angle, height, and thickness. You can also do a screen capture of your design and parameters in Fusion 360. Now it’s time to actually make the bowls.
Step 3: Make a Bowl Blank From Wood Segments
Make a bottom board that is about 12 inches by 12 inches square. Mark an equilateral triangle with a side-length of triangle_side from step 2 in the center of this board, and drill 1/8" holes A, B, and C through the board at the triangle corners. It is important that the spacing of the three holes is准确和等距(e.g. 3.8 inches). The attached pdf file (triangular bowl sketch) will help in the layout.
步骤4：Trircle Cutch夹具 - 非常简单！
您准备构建一个非常简单的切割夹具。乘以12英寸x 15英寸的MDF或胶合板板（实际尺寸不是很关键），并从一侧到另一侧，而不是对角线！如PDF图（夹具尺寸）所示，在中心线上标记孔位置A和B在距离边缘6英寸和9.8英寸。通过A和B的夹具板钻1/8英寸的孔。exactlytriangle_side inches (e.g. 3.8 inches) apart toexactlymatch the holes of the bowl blank from the previous step.
For cutting I am using a 1/4" wide bandsaw blade. Set your bandsaw table to 25 degrees (the angle from step 2 above, or whatever angle you designed for the side of the bowl - 10 to 30 degrees is good); and set the fence to about 2” from the blade. Make a single cut into the jig up to the center line. Clamp a stop block to the fence against the jig so that you can reliably repeat the cut to the centerline in the following steps.
Step 5: Cut the Trircles
Place the bowl blank on the jig so that you can insert two pins (8d nails work well) through holes A and B进入the holes in the jig. You are ready to cut the perimeter of the first bowl.
Turn on the band saw and run the jig against the fence up to the stop block/centerline. This will make a tangential cut into the bowl blank. Turn off the bandsaw. Clamp the jig to the band saw table so it won’t move or slide off, or hold it in place. Then remove the pin from hole A (closest to the blade), turn on the band saw, and slowly rotate the bowl blank clockwise to continue the cut. You pivot around point B. Stop when hole C lines up with the open hole in the jig, i.e. at 60 degree rotation. You completed the first large arc cut. Turn off the band saw.
Insert a pin through hole C into the jig, remove the pin in hole B, and make the next 60 degree cut until hole A lines up with the open hole in the jig. As you pivot around point C you make your first small arc cut.
Then repeat the same procedure making 60 degree large/small cuts until you made it all the way around. Turn off the band saw and unclamp the jig. Carefully back the jig out from the blade and discard the outer waste piece.
该技术通过削减公司工作nsecutive arcs at 60 degrees each. A large diameter arc is followed by a small diameter arc, large diameter arc, small diameter arc, etc. The transition from large to small to large is perfectly smooth.
Move the fence to the left by about 1/2” (12 mm). This determines the wall thickness of the bowl. Then repeat the same procedure as above. When you are done you will have the first trircle shaped wall-ring. There is a tangential split (entry cut) at the start of the ring that you will have to glue back together. I have found that with careful cutting/glueing the split is nearly invisible in your final bowl.
Continue cutting wall-rings until you run out of wood towards the center, or until the blade gets too close to the pivot points and can't cut the small arc. The last picture above shows the bottom of the bowl blank where I was unable to cut the very small radius around the pivot.
The resulting bowls will nest nicely into each other. Depending on your glued-up blank and angle you may get from two to four nested bowls.
Step 6: Alternative Glue-up
I prepared a different bowl blank that may be easier to make; but not as good looking. It is also a little more difficult to cut the wall-rings cleanly as the bandsaw blade tends to follow the long-grain. Pictures only!
Step 7: Finish the Trircle Bowls
步骤8: Wait, There Is More!
You don’t have to stop attrirclebowls. The same approach can be used for oval, rounded square/rectangle, five-sided pentagon shaped bowls, and even higher polynominal shapes.
Ovals: use four pivot points, and e.g. 38 degree and (180 - 38) = 142 degree arcs (angles vary with design)
Rounded rectangle: use four pivot points and three different arcs
Pentagon: use five pivot points and 36 degree arcs
Of course you can also 3d print the bowls from the Fusion 360 mesh files! I’m showing one small trircle bowl, just for fun!
And the last picture is a ceramic bowl made with the help of a wooden trircle mold.