Ball bearings were indeed used in very popular tonearm designs at all times. Todays high tech manufacturing allows to create bearings with incredibly low tolerances. The bearings used in the schick arm have 0 (zero) positive tolerance and 7µm negative tolerance. From a perfect ball the negative tolerance means ‘dents’ with 7µ depth. Since there are many balls holding the construction the probability of really having 7µ tolerance is extremely low. This gives an extreme stable connection between the moving parts.
top quality ball bearings
Low tolerance gives the bearing another desired property: quietness. Obviously noise of the tonearm bearings would cause movement and resonances in the arm, that would cause a loss of information again. The low tolerance surface is achieved by polishing, which makes the surface of the modern ball bearing very smooth and silent if turned. It is possible to buy an identical looking bearing for a fraction of the cost. Turn them and put them to the ear. You can hear already metallic scratch noises, nothing you would like to have in the music signal.
Just turn a vintage arm horizontally and you know what I mean. There just loose balls arranged around the tonearms parts are used.
The low tolerance and smooth surface has a third important advantage: low friction and low stick effect.
The mechanical momentum necessary to start moving is very low. Thus the cartridge will again track better. The super smooth surface also makes the friction very low. We are talking of values where regular grease would be like fixing glue. For lubrication a special very light synthetic oil is used that will last a lifetime.
A word to the life expectancy of the bearings. They are made to withstand really high revs. That will never occur in their tonearm life, but ensures their quality for decades.
Apart from the crucial moving part of tonearms, another important issue are the resonances. Metal is usually a good resonator, which is bad. But metal is strong and rigid. In a mechanical assembly the resonances of the metal can be kept very low. If two ‘ringing’ pieces of metal are brought together and joined mechanically, they do not produce any sound anymore. So the use of a headshell is a very good treatment for arm resonances. The mechanical interface between the arm tube and the headshell connector also controls the resonances very good. The same applies to the pivot axis and the counterweight. All three elements are safely joined together in order to control the resonances.
Special care was taken with the damping of the tonearm tube. Three different materials in 9 sections are used here.
The schick 12 and schick 9 inch tonearms are designed to follow the Baerwald geometry. This allows the smallest amount of tracking distortion over the whole record, for a given length.
However, to optimize an arm for one certain radius is just as possible, as using Lofgren or Stevenson geometry by changing the cartrige position in the headshell.
12 inch tonearm:
Null at 66, 120,9mm Baerwald
Mounting distance 304,75mm
Offset angle 17,11
eff. Length 317,5mm
9 inch tonearm
Null at 66, 120,9mm Baerwald
Mounting distance 229mm
Offset angle 22,345
eff. Length 245,8mm (9,6 inch)