I may be the person of whom you speak. I still don't believe that the abrasive dust was added to wear the needle rapidly but rather for strength and hardness to stand up to the force of the acoustic sound boxes of the day. The rapid stylus wear was a "side effect". Material science was relatively primitive in the day. Even for the day better approaches could have been had. Edison Diamond discs were played with acoustic soundboxes with diamond styli and the playing surfaces were made of an early polymer with no abrasive material added. While that system had to be more expensive it was quieter.
H. callahan wrote: ↑13 Jul 2019 04:19I assume that he machine+soundbox used for this test was in fully working condition, otherwise the test might have shown a different result.Bob Dillon wrote: ↑12 Jul 2019 23:26Interesting that it appears to show little to no wear. Of course, that is on that particular machine with a new steel needle every play. Might have been interesting to hear the record after the first play on the gramophone, then played on a modern hi-fi turntable. Then hear the 100th play on the gramophone again on a modern turntable for comparison. The results may be more revealing of wear having set in. As one of the commentors in the video noted, alignment is important. Some of those old acoustic phonos made really no provision for proper offset of the reproducer to the record groove wall. The old style Columbia machines with their straight arms are one example of that. The reproducer needs to be in good working order too, with a pliable diaphragm and rubber gaskets, so that the movement of the needle is not restricted, thus reducing unnecessary record wear. Not unlike the suspension on a modern phono cartridge.
When comparing the 1st and the 100st play i can hear very small differences, surface noise has increased and there also is distortion on high frequencies - but in the "shellac-world" the record still is in veeery good condition after a hundret plays, almost like new. We´ve had it in another thread where one person did not belive abrasive materials being in the shellac-mix to shift wear onto the needle, but this test does show that the idea of shifting wear from the record onto the needle can work pretty good.
I think one of the reasons why the record held up that well is that the surface of the groove still was undamaged. When playing a record having grey grooves there usually is more shellac-dust on the needle - so it seems that a shellac will wear faster once the groove is damaged.