The top consist of two sub-assemblies: The lower half and the upper. The lower half is made up of two plywood sheets glued together, edged with maple and joined using doweled bridle joints. The doubled up plywood is attached to the frame using a basic butt joint strengthened with 3/8” dowels and glued down with epoxy. I used this method because my wood was not wide enough for the desired final dimensions if I rabbeted in the panel. This simple butt joint gave me some additional width and the dowels and epoxy give it plenty of strength.
I used a pocket hole jig in a non traditional way to make dowel alignment simple. The glued up plywood is first drilled in the usual way using a standard pocket hole jig. After assembling the frame, I aligned it with the plywood base and drilled the 3/8 holes deeper into the frame to hold the dowels. After the glue dried, I used a Jsaw to cut them almost fllush then sanded the rest of the way. A trick to using the Jsaw for this is to put some tape on the saw. This raises the saw just enough so there are no saw marks on the surface. I could have used screws here, but I have wanted to try this joint and this was a good opportunity.
The block at the top is for mounting the end vise. The end vise is all metal, so I lowered and recessed it to clamp mostly with wood. The two big holes are to make it easy to pop out the upper half when it needs to be removed.
The upper half is just two 3/4” plywood panels glued together. It fits in the recess of the lower half. Wood screws attach it to the lower assembly and keep it flat. The screws are well below the top surface so that any tools I may use have no chance of being dinged. Screws work better then any wood joints I could think of for this purpose.
The dogholes were drilled with the bench assembled and the top screwed down so there is no jiggle. I used a router with a ¾ up-cut spiral bit to keep the dog holes aligned vertically. The router was held in a jig to make sure it did not move. Since the combined table is 3” thick, I had to finish up with a spur auger bit in an electric drill. I tried some other techniques to drill the dogholes, but they did not work well for me. I had to go back and glue in some dowels to fix some angled holes and re-drill with the router. Also keeping track of your screws is important. I caught one and ruined a router bit.
The top is attached to the legs with six 3/8 lag bolts recessed into the rails. I took extra care to make sure that the front edge was flush with the legs since this would be the clamping surface. Any minor irregularities were kept on the back of the bench. The leg/shelf assembly is reasonably stable by itself, but when the top is securely attached it makes everything rock solid.
The chop came from my home milled maple stash. It is about 2” thick. I first drilled the rounded corners with a Forstner bit and then cut the straight sections on my bandsaw. A jig saw or Japanese handsaw could have done this but would have taken much longer. The chop is canted the same 15 degrees as the leg. The top hole is for the screw mechanism. The hole for the screw is drilled oversize so wood does not contact the screw. This is designed so that the only contact is with a brass plate mounted to the front of the chop. This plate is drilled and threaded so that it can be mounted using 4 machine screws via recessed holes on the back of the chop. Below that and hidden by the brass plate when assembled is the hole and recess for holding the end of the chain. Finally on the bottom is the hole for the end of the linear bearing rod which only penetrates about 2/3 of the chop from the back. I drilled it exactly 1” but I had to taper it slightly on the side since the clamp was not closing parallel horizontally. There was a 1/16 gap on one side. The taper allowed some rotation of the chop side to side for a tighter clamp. I planned to epoxy in the shaft when it was all properly aligned, but it does not look like that will be necessary. Leaving it loose seems to allow for clamping items that are a little out of parallel and the chain pulls the shaft tightly into the chop when clamped. I will need to use it for awhile to see if any issues show up, but it looks good so far. The other benefit to leaving it loose is that it avoids any alignment issues with the screw.
The top of the chop is left overlong until all the assembly issues are taken care of. To finish up, I cut the top flush to the table, routed a cove around the edges and rounded over the top of the chop for a little extra clearance.
Here are the wooden parts with the bench disassembled. They are portable and can be carried by one person, though the lower top is quite heavy and pretty close to my limit.