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Bob''s Flashes - Drag lines and polishing lines

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dimonbob

Brilliant_Rock
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During the polishing process if the polisher is not using a clean lap, has left over grit on the the lap, is not patient, is in a hurry, or someother reason, he may end up with drag lines or polishing marks on one or more facets of the diamond.
A drag line is caused by the leading edge of a facet or open feather on a facet crumbling slightly and dragging the tiny diamond piece across the facet leaving a scratch or, in this case, a drag line. When this happens there are usually more than one or two lines. Polishing marks are usually caused by a dirty lap, an inexperienced polisher, the polisher not paying attention, or settling for a "good" polishing grade from GIA. An excellent polish takes a lot more time and experience and leaves no polishing marks.
I will be out of pocket for the next several days but I will return next Monday.
 

pqcollectibles

Ideal_Rock
Joined
Feb 22, 2003
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3,441
Luv the new Flashing Bob!


But, I gotta ask. What's a lap? Relating to finishing wood. Is it like the pad/belt on a finish sander?

Thanks much for these very informative posts, Bob!
 

dimonbob

Brilliant_Rock
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Dec 12, 2000
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670
Hi PQ,
A lap or scaife which is a metal wheel or disk that turns at a fairly high rate of speed. It is in the same plane as the table that it is on. The diamond is held by a dop which is clamped in a tang. The lap can have up to four diamonds on it at a time in these tangs. This keeps the man working the lap quite busy because he is constantly picking up the tang and looking at the diamond with his loupe to check the progress of what he is doing.
 

pqcollectibles

Ideal_Rock
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Feb 22, 2003
Messages
3,441
Thanks, Bob! I think I get the idea. Busier than a one armed man in a wall paper hanging contest, sounds like!


I worked for a Geology professor in college. His research is world famous to people that need to know about him. He patented a method to restore rock/brick/stone. When working on a historic brick building, we "made" new color matched bricks to replace weathered, crumbling ones. That required color matching, molding, and cutting the new bricks. We cut them one at a time to exacting specifications to match existing brick, but the operation sounds similar. We could also perform spot patch and repair holes or crumbled corners to revive the look. We would then "treat" the the remaining brick on the building to improve it's ability to withstand weathering. Buildings weren't the only thing we worked on. We restored markers in a historic cemetaries as well. But, probably the most significant project he worked on while I was there were the Sphinx in Egypt. No field trip for me on that one
, just the research aspect. Sometimes the little people get no glory at all. LOL


Thanks again, Bob. I learn more everyday!
 

anniediamond

Rough_Rock
Joined
May 5, 2003
Messages
18
Hi Dimonbob!

This is way more advanced then I am ready for, but...
Are drag lines deeper than polishing lines? Also, can they be polished out???? If still visable, would these be mentioned on the diamond certificate??

So much to learn, it's great having experts like you here to help!

Thanks,
Annie D
 

dimonbob

Brilliant_Rock
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Dec 12, 2000
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670
Hi Annie,

Yes, drag lines are deeper than polishing lines. They would show up as a scratch on the grading report. They can be polished out but the trick is not to cause more drag lines.
 
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