Q:
The shoulders of my tenons never line up perfectly when I cut them at the tablesaw. I use a dado blade and a miter gauge. What’s going on and how do I fix it?
Jeffery Lish, Castle Rock, CO
A:
A dado blade is a great way to cut tenons quickly and accurately. But if everything isn’t set up correctly, it’s easy to get uneven shoulders, which makes it difficult to get tight joints. The good news is that by starting with square stock and dialing in your miter gauge and rip fence, you should be able to get clean, even shoulders right off the saw.
After ensuring that your dado set is square to the saw’s table, check that the ends of your stock are square. Any angle on the ends will result in the shoulders on the edges of the workpiece being proud or undercut. Next, check that the face of your rip fence is square to the table. If it is angled, it also can result in shoulders that are proud or undercut. Finally, make sure your miter-gauge fence is square to the miter slot. If it’s not, then the shoulders on the face of the stock won’t be parallel.
Problem: Proud or Undercut Shoulder
Two ways to get a top or bottom shoulder wrong. A proud shoulder is easy to fix with a chisel. But it’s an undercut shoulder that woodworkers really dread, because it can’t be fixed easily.
Solution: Check for square before cutting. The end grain needs to be square to the edge, but a fence that’s not square to the table could also cause proud or undercut shoulders.
Problem: Shoulders Not Parallel
Too high on one end. This is a telltale sign of shoulders that aren’t parallel. The shoulder on the other side will be high on the opposite edge.
Solution: Square your miter gauge. Use a drafting triangle to set it to the miter slot. You’ll get square cuts even if the slot isn’t perfectly parallel to the blade.
Photos: Staff
Fine Woodworking Recommended Products
Veritas Standard Wheel Marking Gauge
Olfa Knife
Suizan Japanese Pull Saw
Comments
Good stuff, Mike, thanks.
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