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Bill part way through sawing of the first side of the rough turned ring. This is a simple job, but one must still be on one's toes to avoid trouble. There is often unknown stresses and strains in materials, wood and metals alike, that can either cause the saw kerf to open or close behind the blade. For this reason, one should never cut entirely through one side of a ring that has not been stress relieved (a heat treating term that means exactly as it reads), for fear of the ring suddenly collapsing as the blade cuts through the inner surface of the tube. Before the operator can turn off the machine, the bound blade, held in the collapsed tube, will either have jumped of the band wheels of the machine, or smoked the drive belts. If a stressed tube opens up, which it never seems to do, no problem. The usual technique is to leave 1/8 inch or so material, back out of the cut, and finish severing the ring by cutting from the outside of the opposite side of the tube, but there are times that this does not work out. See the next shot.
Photo by Bill Liebman