Group,
I performed a quick calculation using equations developed by Hertz (sphere to sphere contact) to calculation how much pressure the stylus applies to an Edison Diamond Disc record for :
1. Edison Diamond Disc Phonograph
2. DJ style of Stylus with 0.7 mil spherical shape and 2 Grams of weight.
3. 3.75 mil "Expert" stylus with 4 Grams of weight.
The results were very interesting! I used the material properties of Bakelite for the Edison Disc Groove and Diamond for the stylus. The PSI (pounds per square inch) values are the "point contact" force which in turn is spread
over the contact area.
Results:
1. 0.00166 sq inch contact and 72,566 PSI
2. 0.00015 sq inch contact and 93,583 PSI
3. 0.00046 sq inch contact and 19,902 PSI
Conclusion : Although the actual force is spread under and around the contact area, the calculations shows that the Original Edison Design was somewhat better than using a LP style and low gram load. The reason is because of the
non-linear relationships in the Hertz equations.
If anyone has other results please let me know.
Marc
I performed a quick calculation using equations developed by Hertz (sphere to sphere contact) to calculation how much pressure the stylus applies to an Edison Diamond Disc record for :
1. Edison Diamond Disc Phonograph
2. DJ style of Stylus with 0.7 mil spherical shape and 2 Grams of weight.
3. 3.75 mil "Expert" stylus with 4 Grams of weight.
The results were very interesting! I used the material properties of Bakelite for the Edison Disc Groove and Diamond for the stylus. The PSI (pounds per square inch) values are the "point contact" force which in turn is spread
over the contact area.
Results:
1. 0.00166 sq inch contact and 72,566 PSI
2. 0.00015 sq inch contact and 93,583 PSI
3. 0.00046 sq inch contact and 19,902 PSI
Conclusion : Although the actual force is spread under and around the contact area, the calculations shows that the Original Edison Design was somewhat better than using a LP style and low gram load. The reason is because of the
non-linear relationships in the Hertz equations.
If anyone has other results please let me know.
Marc
Comment