I’m going to have end caps on my bench, which will work something like a scaled-up breadboard end. The purpose isn’t to help hold the top flat, though. On the right end – where the wagon vise is located – the end cap holds the vise screw in place. On the left end, the end cap is mostly to balance out the look of the right end.
It is a big slab. Approximately 25” wide and nearly 4” thick. Even if I had a euro-style slider saw with a 12” blade, I’m not sure the sliding table would take the 200-lb weight of the slab. Although that would be a very easy way to make the necessary cross cuts.
Neither do I have the patience to use a (hand-powered) panel saw to work something this large. Don’t know if I could be as precise as I want, either.
So I resorted to using my trusty circular saw. Even went out and bought a new blade.
The biggest problem when using a saw when you have to cut from both side to make a through cut is to get the cuts to line up. The solution is to build a collar that you clamp around the piece. The collar just needs to have guide faces that are coplanar and perpendicular to the piece. It is pretty straightforward to make.
Take a couple of scraps – plywood or hardwood – maybe 4” wide and a bit longer than the piece is wide. They need 1 face and 1 edge flat and squared to each other. Also cut a couple of blocks to be just longer than the piece is thick – maybe by 1/64” to 1/32”.
Using a flat assembly table, build something that looks like this:
The blocks are spaced so the collar can slip around the slab. Easy!
Second step is to make sure the saw blade is 90° to the base
Third step is to measure the offset from the blade to the edge of the saw’s base. In my case, 5 1/16”.
Next, lay out the cut lines:
Line 1 is the outer end of the tongue, while line 2 is the inside shoulder. Lines 3 and 4 are then offset by the saw’s cut offset.
Slide the collar over the end of the slab and clamp it on Line #3 to start:
Set the saw blade to cut through 1/2 the slab and then make the first cut with the saw against the guide. Then, keeping the collar clamped in place, flip over the slab and make the second cut:
In this case, I didn’t have the saw blade extended quite enough. However, the remaining bit was easy enough to break by using a mallet.
You’ll notice that the cuts don’t quite line up. Assuming your technique resulted in even cuts on both sides, this means that the edges of the collar aren’t perpendicular and coplanar to the slab face. Using a square to check, I shimmed one edge of the collar using a couple strips of masking tape. All is good:
Flip the slab back over and reset the collar to line #4. And reset the saw blade depth to be the shoulder depth you want. In my case, 1 1/4”. Make the cut:
Here’s the easiest way to cut the rest of the tongue’s shoulder – use your saw to freehand closely spaced kerfs:
The kerfs should be spaced closely enough so the you can easily break off the remaining strips of wood with finger pressure. Then use some sharp friends to clean up the shoulder. I used a slick, a chisel and a router plane but there are other ways to skin that cat…
Make sure the collar stays clamped in place during the kerfing and cleanup, because you need to flip the slab over and repeat the process.
Voila – you now have a tongue on the end of the slab.
-- Mark Kornell, Kornell Wood Design