Ball Bearing Tone Ring

The ball bearing instruments differed from the others by having a tone ring that was mounted on ball bearings which sat upon heavy steel springs and washers.

Ball bearing tone ring.

The old two piece flange rim was probably the heaviest rim not the ball bearing which had holes drilled in it. While the exterior beveled appearance of the head remained the same the new tone ring construction is evident inside the body with some of the earlier raised head rings having no holes. The twenties mastertones underwent a significant evolution from 1925 to 1930 during which time the tone ring rim and flange changed quite a bit. But a heavy rim might work well on a cut down tpf rim.

Ball bearing tone ring. A good banjo at a good price. One of the resonator wall lugs is missing. Circa 1927 all mastertone models including style 3 changed from the ball bearing tone ring to a cast metal raised head or archtop tone ring.

Ball bearings are used with applications that have high axial loads and low to moderate radial loads. Most modern banjo players believe that the purpose of these springs was to maintain a constant tension on the old fashioned skin banjo heads that were in use until the late 1950 s. I would not be surprised if this issue alone was the cause of heated discussions between loar and gibson management resulting in his departure in 1925. Self aligning ball bearings such as the wingquist bearing shown in the picture are constructed with the inner ring and ball assembly contained within an outer ring that has a spherical raceway.

The reasonfor the change was economic not artistic or even to enhance the sound but it did develop the characteristic gibson sound of the thirties. Mounted bearings bearing units have a bearing inside a housing unit to ensure a secure fit and mount. The ball bearing tone ring system was without question a major step forward but it proved to be prohibitively expensive to produce as well as a nightmare for head replacement in the field. 41 get it as soon as thu oct 8.

Gibson ball bearing banjos. The pot still has the skin head. The resonator has a very dark almost black stain and appears to be original but i can t be sure. This construction allows the bearing to tolerate a small angular misalignment resulting from shaft or housing deflections or improper mounting.

Big bearing 7616dlg ball bearing with set screws and snap ring 1 shaft size 2 outside diameter 1 179 inner race width 0 625 outer race width pre lubricated metal 18 41 18. Then the so called fat boy then the 5 8 thick of the 30s.