Here we go into another new week. Today I continued in the process of parts making by laying out and cutting the tenon shoulders and cheeks.
This starts with a marking gauge, which uses a small knife blade to score a line where the tenon shoulder will be. Because the marking gauge can be set for the exact distance from the end of the board and the knife makes a cleaner, finer line than a pencil does (and because pencil is hard to see on a dark wood like walnut) I prefer using a marking gauge over a ruler and pencil.
Then we do a little set-up on the Incra Miter Fence so that the edge of the saw kerf falls precisely on the marked line, and cut the tenon shoulders. The end rails are shorter than the door rails, which are shorter than the back rails all of which are different from the center stiles – but they all get tenons. All but the center stiles are a 2” long tenon, so the blade height remains the same for all of them, but after each set the fence must be recalibrated for a new board length.
When done each end of each board has a groove cut completely around it which serves as the transition of the tenon. Some folks will simply put a dado head on and cut the tenon cheek and shoulder all at once. But I find that this tears out the wood pretty badly as such a large blade exits the wood, making for an ugly joint.
The next step is to cut the cheeks. I use my shop built tenoning jig for this. It hold the rail upright and square to the blade, supporting it and the rail passes through the blade. Two things I find helpful; first I lightly sand the shoulder cuts to remove the “fuzzy bits” that are bound to be there. These bits can hold the rail out away from the tenoning jig just a hair, but a hair off each side means the tenon will be too thin and won’t fit into the mortise well. A sloppy joint is a weak joint. The other is that I chop a correctly sized mortise in a scrap piece of wood and keep it handy. As each tenon is cut, I test fit it into this test mortise to insure a precise fit.
At the end of the I have a pile of parts with very clean, well fitted tenons.
Tomorrow we'll cut the haunches and start chopping mortises.