Here we go with another photo heavy blog segment. I’ve explained the reason for all the detail before so let’s just get into today’s work.
With the leg assemblies all glued up, the next job is to tie them together into a rigid, rack free unit. This involves parts AC, AD, and AE in the plans. Start by marking the width of the lower stretcher cover from the work. This will be close to the dimension in the plans but almost certainly won’t be exact so mark it from the work.
Next take a measurement from the work for the overall length with the stretchers (AE) in place.
Mark and cut the appropriate notches for the posts and dry assemble with #8×2” screws. Remember that the plywood won’t split if you drill for them. Check that the stretchers are a tight fit between the leg bases. This is the critical fit that makes the bench rigid.
Repeat the process for the top, again insuring that the stretchers are tight between the top leg beams.
Mark the spot where the stretcher cover meets the leg …..
... and corner round the edges except that bit in way of the leg.
Spread the stretchers with glue, locate the screws in their old holes and assemble the stretcher box unit.
Check one more time that the fit is still tight and glue the unit in place.
When you have repeated the process for the top box, you should have a rigid little unit that looks like this.
Now get out the bottom of the torsion box top and let’s cut the wagon vice hole. This involves drawing a hole only 2 1/4” wide centered inside the traced line that we made when we had it assembled. When you have multiple lines, always put ticks on the one you want to cut.
I chose to cut the sides of this hole by hinging the skilsaw down into the line as it gives a cleaner, straighter cut than the jig saw. If you aren’t comfortable with this don’t do it. Use the jig saw.
You have to use the jig saw for the ends anyway. When making cuts like this with a jig saw you might want to cut a little inside the line and clean it up later with a router and a guide. Jig saw blades like to wander on the bottom side of the cut. I’ll cover this later.
Now, with the outer frame screwed and glued together and the long dog hole log installed, spread glue and screw down the bottom. (shown upside down of course)
This is a photo taken later, when I was assembling the top but I’m inserting it here to illustrate a point that you should always consider when building with plywood that isn’t flat. You can make it work for you. I should have mentioned this before but it’s something I do without even thinking about it, like checking for grain direction. In the case of these pieces, I laid them out so that the cup was up. That means that when you screw down the edges, the center is under pressure …. self clamping! There is no need to put screws in the dog strip area. Of course you can if you want or if the cup is the other way.
Next, glue up and install the short dog hole log and clamp in place. The holdfast is just there for alignment, not holding anything.
Then add parts “P” and “U” working quickly.
Now add the cross members and clamp everything. (Love those $2 clamps)
Now, just to be accurate, replace the top in it’s screw holes and re-trace the wagon vice hole. It is very important that this be as accurate as possible. When removed, as you can see, it is a bit off it’s old marks.
To avoid confusion, I made tack holes at the corners of the good line and then sanded the lines off. I then redrew only the good line and worked from it to lay out the actual hole to be cut.
Now you can glue the bottom / framing unit down to the leg assembly with lots of 2” screws. The critical alignment is that the first dog hole on the left should line up with the center of the leg vice and that the plywood box should be flush with the front of the leg vice leg.
With the hole cut out of the top sheet with a jig saw (slightly inside the lines), you can go ahead and glue the top in place and clean up the edges. I had planned to make the facing boards out of hardwood but since there was plywood left over, I cut them out of it and dry assembled them.
So there you have it, two sheets of plywood put to good use. I still have some scraps left over.
There’s nothing left but vices and lipstick and we’ll get to that tomorrow.
Thanks for looking in.
-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fibreglass trees. http://thecanadianschooloffrenchmarquetry.com/