- 2/3/07
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Maybe this has been discussed before; if so, my apologies in advance. I come from the gen world and don't have much experience with this.
I was recently servicing an A7750 that had all sorts of issues. During disassembly I discovered the jewel for the great wheel was shattered, pinched between the driver cannon clutch and the great wheel. I only found 2 pieces, leading me to believe it was broken during assembly. The first thing I did was inform the owner. Then I pressed a replacement jewel out of a parts movement and installed it, and everything is running nicely now.
A couple days later I was taking a closer look at the fragments and tried breaking one with a screwdriver. To my surprise, it split rather easily. I tried again on one of the resulting fragments, and it pulverized into dust without any difficulty.
I obviously have experience with pressing and working with jewels, both intact and broken. This "ruby" was actually just pink colored glass. No way it was a 9.0 on the Mohs scale. Remember, ruby is essentially pink-colored sapphire (like the crystals on most of your watches) and is extremely hard and very difficult to even scratch, let alone pulverize. Sapphire is the material used in the counter-mount bar code scanners at your local retail store; cans, foods, hardware, tools, etc. are all dragged across it all day every day for years and months with little effect. That's because only moissanite and diamond are harder on the Mohs scale.
Still haven't decided whether or not this is a bad thing. My first instinct is that this shouldn't be a problem if proper lubrication is present, but I have to give this some serious thought. Just be aware of this new feature.
I was recently servicing an A7750 that had all sorts of issues. During disassembly I discovered the jewel for the great wheel was shattered, pinched between the driver cannon clutch and the great wheel. I only found 2 pieces, leading me to believe it was broken during assembly. The first thing I did was inform the owner. Then I pressed a replacement jewel out of a parts movement and installed it, and everything is running nicely now.
A couple days later I was taking a closer look at the fragments and tried breaking one with a screwdriver. To my surprise, it split rather easily. I tried again on one of the resulting fragments, and it pulverized into dust without any difficulty.
I obviously have experience with pressing and working with jewels, both intact and broken. This "ruby" was actually just pink colored glass. No way it was a 9.0 on the Mohs scale. Remember, ruby is essentially pink-colored sapphire (like the crystals on most of your watches) and is extremely hard and very difficult to even scratch, let alone pulverize. Sapphire is the material used in the counter-mount bar code scanners at your local retail store; cans, foods, hardware, tools, etc. are all dragged across it all day every day for years and months with little effect. That's because only moissanite and diamond are harder on the Mohs scale.
Still haven't decided whether or not this is a bad thing. My first instinct is that this shouldn't be a problem if proper lubrication is present, but I have to give this some serious thought. Just be aware of this new feature.
