Do I really need to score polishing laps and if so how?

There are a lot of different opinions about scoring, but in my experience, I think it helps. I have cut a lot of stones and tried polishing about every way I can think of, but scored laps seem to work better and faster.

If you are not sure, you can always score your lap later. After you have tried it un-scored, it will not hurt anything. It is hard to take that pretty new lap and cut it up... I know, but this does work, and all the old pros I know, score their laps.

 

 

Yes, at least for me, scored laps work much better than non-scored laps do. Scoring helps keep the polish on the lap where you want it and also gives the chaff/waste a place to go that will not scratch your stone. I score all of my Tin and Zinc laps whether I am using Diamond, Cerium Oxcide (CO2), or Alumina Oxcide (AO2).

Scoring is easy to do and there are many ways to do it. I use an old piece of hacksaw blade (you can use a razor, knife or whatever, I like the hacksaw because it is fast) about 2" long and drag it (scrape to make grooves) from the center (mounting hole) of the lap straight to the outside edge all the way around.

Then turn the lap 90 degrees and score across the lap to create diamond shaped grooves where they cross each other. The little diamond shapes hold the polish...

After scoring I wipe off the loose bits, and then if you want you can put some polish and water on it and use an old piece of Garnet or Tourmaline to help knock off the burrs (I usually do not bother).

Note: Be sure not to use something hard like CZ, if you accidentally imbed a piece, it will cause scratches.

When your lap is new you will notice some metal accumulates on the edges of your facet(s) and there might be some slight rounding, it will wipe off and does not hurt anything.

As your lap breaks in, it will begin to work harden and not do this much at all, and will polish flatter facets, also as it is used it will start to polish faster and better. When you have used the lap a while and it seems to slow down, score it again.

 

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