shaker bench - the fix
I did not think I would be repairing the shaker bench so soon! As Dan commented, I have made a pretty major structural error. This is one of those sad instances where, in hindsight, you cannot believe you overlooked it. I oriented the half-blind dovetails on the end cap the wrong way. The force from the wagon vise is not at all supported by the dovetails.
What to do.
I spent a good part of that morning thinking about the options. I could put a few lag bolts through the end cap into the main part of the bench. This would be easy to do and would solve the problem. Trouble is - I really did not want to disturb the clean surface of the end cap. Set this idea aside to see if there was another solution. I then thought of adding a steel plate to the underside of the end cap and connecting it to the front apron. Jameel suggested moving one of the wagon vise rails forward so one of the screws also tied into the end cap. Moving the rail and adding a steel plate seemed like a pretty solid solution - so I went for it (and I could still add the lags if this failed).
Unfortunately - the Metal Supermarket had closed early and I was not able to get a piece of 1/4" steel for the plate. You would think that a guy who makes planes would have lots of scrap material on hand... nothing. Then I remembered the spare base plate for a jack post. It was 5/16" thick and had three pre-drilled holes in it. With some careful arranging - I could get the piece I needed and avoid all the holes but one. I was able to position the hole where I needed to make a cutout for the rail anyway. Unfortunately - this meant a lot of extra cutting. About 5 minutes in, elbows burning, I reminded myself that this was my punishment for making such a stupid mistake. It was about 1/2 an hour of hacksawing but the rough shape was done. Thankfully, I am fairly efficient at using a hacksaw and there was minimal filing and clean up to do on the edges.
Here is the plate in position with the wagon vise rail re-located. It took a few minutes to arrange the positions of the screws. There were quite a few other holes in the end cap already and I did not want to turn it into a piece of Swiss cheese. From left to right; the two left most screws catch the front apron only. The next one in catches a solid part of the end cap. The screw in front of the rail catches the solid part of the end cap and the last screw catches the end cap as well as the tenon of the main part of the bench.
I really debated on trying to locate a screw through the 1/2 blind dovetails, but I was worried it would compromise them structurally so I opted to position 2 screws in the solid section above the front apron.
Now that I had the top off (again) - I had an opportunity to take a few photos of the underside of the wagon vise. I was not sure if my explanation of the traveler covering the hardware and providing a “dead zone” above the base leg made sense. In the above photo, you can see the large nut is just proud of the Honduran Rosewood. This was done so the nut would bottom out against the end cap and not the wood. At least I took clamping force into account this time.
You can also see that the dog hole is positioned as far forward as I could get it with the pre-drilled hole in the hardware.
Hopefully this will take care of the it. If there is a problem, I will likely know about it rather quickly - this bench will see a lot of use. And while this whole thing has been quite embarrassing - Dan, thanks for catching this. I would rather deal with it now than after something went “pop”.