The Von Trap(ezoid) Table

Instructions

Prepare legs. Leg material is 7/8” thick, 1 3/4” wide and oversize at about 21 or 22”. Using a miter saw or miter jig, cut one end of each leg at 11°. Measure and mark one edge at just over 20 inches so that you have enough to cut a tenon that is thicker that 3/4”. Set a stop block and repeat cutting the other three legs the same length. Cut the leg tenons. Use Workstation with the vertical clamping plate and the 11° shop made fixed angle block (svg for Origin or 3D print files are included), set the leg blank against the Workstation stop bar. Grid off of the leg front and left side. Your anchor point will be top left. The tenon file should sit so that the bowtie shape is towards the right side of the rectangle. The tenon will center itself and you cut downward. Using a 1/4” bit, cut the tenon to a zero offset, you can use a positive offset to clear to the outer edge of the leg. Cutting depth is 3/4” +0.005”. After the leg tenons are cut, taper the legs using tapering jig. Cut the outside of the leg just past the flat where the tenon is down to the bottom of the leg leaving a 1 1/4” wide bottom. I also chamfered the legs about an 1/8 of an inch. Shelf supports. Cut the tenons using Workstation’s vertical clamping plate. Align the parts either with the reference pins or the adjustable fixture set at 90°. Grid the part and anchor the file to the top left. Using an 1/8” bit cut to a depth of 3/4” +0.005”. Chamfer parts to your choice. Cutting the angles for the top and shelf. According to Fusion, the angle from the back edge to the side is 80.538°. If you can achieve 80.5° that is close enough. Just make sure they are all the same. That angle is the same for both the top and the shelf. Mortises. There are any number of ways to setup and grid your workpieces, here’s how I did it. Use Workstation, the shelf and put the clamping plate in the top position. If you have access to a 3D printer, the included files for right and left references are very handy. The resulting parts need heat sink inserts for 6 mm bolts. If you can’t get the reference blocks printed, make some sort of right and left reference block that will butt up against the clamping plate. Grid one side and then the other creating a right and left Workspace. Probe against the clamping plate and the respective right and left side. Cut the mortises in the shelf from the top side using an 1/8” bit. The side of the shelf will go against the clamping plate and the corner that meets the back edge will go into the intersection of the clamping plate and the respective side reference. When you import the shelf svg file it will need to be rotated to get it oriented properly. The number is 99.5° to orient on the right side and -99.5° to orient on the left side. After the file is rotated, set the anchor point at top left and top right respectively and position it at 0, 0. Follow the same steps using the same Workspaces for the top. For the top panel mortises make the cuts from the bottom of the workpiece. Back bevel. I used a table saw and fence with a vertical clamping jig to cut back bevels at 55°. For all four sides of the top and front and rear of the shelf, set the table saw blade at 35°. Position the jig face 1/4” away from the base of the angled blade using a 1/4” spacer or setup block. Clamp the workpiece so that a side is flat on the table. For both pieces the bottom side will be facing the blade. Cut all four sides of the top and only the front and rear of the shelf. The shelf sides can only be cut at 20°, otherwise the cut will be into the support mortises. Cut using a miter gauge set to 9.5° and the blade set to 20°. Match the cut distance so the remaining flat matches that left on the front and rear faces. Do your final sanding, assemble and apply finish.