Turning Tenons

Turning tenons is the process of turning down the cylindrical projection at the end of the mouthpiece (stem) to the diameter that will fit the mortise bored into the shank. This is the single surface that joins the pipe's two parts together, which is why it's considered the least forgiving stage of pipe making.

Even a deviation of one percent of an inch in tenon diameter changes whether the fit ends up loose or forced. For its place in the overall process, see the how a pipe is made entry.

Tolerance and Equipment

This is not a scale that can be held to with a wood lathe's dial; the work is mostly done on a metal lathe. What the metal lathe brings isn't so much precision as repeatability: a second part machined at the same setting matches the dimension of the first. The Taig Micro Lathe II, common in small workshops, is described in manufacturer and distributor documentation as capable of roughly 0.0005-inch working precision. Since the same lathe is also used in the workshop for drilling on the lathe, the mortise and tenon are often prepared on a single machine and with a single sense of axis.