Initially, the 2001 bandsaw was extremely wobbly but I aligned it and tried to use it. I broke two couplers, first one of the old yellowish-white translucent ones that was probably original equipment on my Greenie and then a newer opaque white one. I initially ignored the first coupler failure, 60+ years seemed okay. But after the second I read a thread here on coupler failures and decided that wobble was like mis-alignment, and now think I overheated the coupler. I worked out that my Accessory Mounting Locks needed asymmetric adjustment because of some manufacturing variation and that has greatly diminished, but not eliminated the wobble.
Before I figured out the lock/clamp problem I mounted the Magna, which had significantly less wobble even without tightening the lock. And I had never had to adjust the locks more than snug with the Magna. With the new bandsaw I find that the tighter I make the locks the more I decrease wobble, even going beyond hand tight.
The Magna has straight mounting tubes where the newer model has the eccentrics. (Small 1/4 inch eccentrics, not offset tubes.) In addition, there are several dimensional differences and features that seem to make the new tubes prone to wobble. Since most readers don't have a straight tube mount to compare, the tubes are similar to those on an extension table. The straight tubes have no horizontal adjustment, vertical adjustment is done with stop collars. I aligned both on the same SS 520 and then removed a tube from each to make these measurements and observations. Objective measurements are eccentric first, followed by straight tube, in inches:
Overall length: 6-7/16 Vs 7-1/2
Length above mount surface: 4-1/4 Vs 4-9/16
Flats above mount surface (ignoring bevels): 4-1/8 Vs 4-1/2
Flats below mount furface: 2.077 Vs 2.841
Corrected: Tube diameter: 1.231 Vs 1.239 (Avg of 6 measurements, variation was +/- .001)
1)The end bevels on the aluminum eccentrics are much more pronounced than on the straight steel tubes. This is important to this thread because only the flat, non-beveled, portion provides support.
2) The straight tube gives much firmer engagement in both bandsaws with the set screw loose. It fits snugly into both collars and goes in all the way to the mechanical stop. The bandsaw setscrew does almost nothing. In contrast, the eccentric fits loosely. It will go in to the mechanical stop but vertical adjustment takes it well off the stop and leaves it only partially engaged in the upper collar. The setscrew is working hard, forcing engagement between the tube and lower collar. Some wobble may come from the lack of engagement between the tube and the upper collar, contributed to by both the smaller diameter and the shorter length of the tube.
3) Similarly, the straight tube gives much better engagement below the mounting surface in the SS headrest. The headrest mounting holes are about 2-3/4 deep, so the eccentrics don't use the full length. With the lock (SPTclamp) loose, the eccentric is a pretty sloppy fit in the mount compared to the straight tube. The smaller diameter and shorter length both contribute. Even the small shoulder of the eccentric compared to the stop collar contributes. Similar to the set screw in the lower collar of the bandsaw, this requires the lock/SPTclamp to do a lot more work to reduce wobble on the eccentric mount.
4) In addition to expecting the lock to do a lot more work, I observe that it is not in the best axis for doing that work. Bandsaw wobble is left to right, toward and away from the headstock. Clamping force is front to back. This seems consistent with my earlier observation wobble diminishes with greater clamping force, including more than I think is intended (beyond hand tight.)
5) Nothing I've seen leads me to think that the eccentricity itself has much to do with wobble. I think the biggest contributor to wobble is the smaller diameter of the eccentric tubes.
I still have a few things to do when I put the bandsaws back together, and re-align them. But based on my observations and measurements, I think that the wobble I am experiencing now is largely inherent to the design of the eccentric tubes, or at least the ones that I have. I became very sensitive to the wobble after breaking couplers, and initially expected to get the wobble down to a level that the design perhaps no longer supports (Magna-like). Also I need to change my expectation that snug engagement of the lock/clamp should be sufficient. Much firmer engagement is needed for the eccentrics.
I've seen several threads that included bandsaw wobble, but I doubt if I've seen them all. Am I missing anything that would explain this better, or perhaps some trick(s) to improve?