Figure 7 – Profiles for 6-Jaw Chuck Jaws
The primary purpose for bezel chucks in my shop is to hold gears so that I can work pivots. As you can see in Figures 6 and 7, 3 of the 4 jaw-profiles are designed to both hold a round work-piece (like a gear) in the center of the chuck – held on 6 sides by the jaws – as well as grip the inside of a work-piece (like a case for a pocket watch or a large ring). While I have used a 6-jaw chuck several times to hold rings of metal from the inside of the ring – most of my work focuses on holding gears so I can work pivots, or, sometimes, hold washers so I can work either the face of the washer or change the diameter of the hole in the center of the washer.
Given my focus on holding gears, I find that the most desirable profile is the bottom profile in Figure 7 – which offers 4 different steps for holding gears. When comparing the bottom profile with the one just above it one can see that the upper profile offers 3 of the 4 steps in the bottom profile, with the last step being replaced by 2 steps for holding rings. Hence it can hold gears, just not as large of gears as the bottom profile.
Likewise, the second profile from the top in Figure 7 offers three steps once again; with the step farthest to the right being very near the tip of the inner end of the jaw (the second jaw from the right in Figure 6 shows this a bit more clearly). This profile does offer the ability to grip the inside of smaller rings than the second profile from the bottom, but does not give as good of a fit for holding gears – in as much there are really only 2 steps that can be used to hold gears.
The top profile in Figure 7 is for a bezel chuck from the late 1800’s – a chuck that was really only intended to work bezels. The steps in the jaws are much shallower – making it pretty difficult to use it to hold gears.
In addition to holding bezels, there were 6-jaw chucks that were made to hold rings or other circular bits with holes in the center. Chucks 2 and 3 in Figure 3 are examples of ring-holding 6-jaw chucks. Figures 8 and 9 show the jaws of these chucks in more detail.