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 Post subject: Diamond topper lap/ review + questions
PostPosted: Wed May 16, 2018 7:38 pm 
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As my Crystalite laps has worn down I've started searching for a good cheaper alternative. I have looked at several toppers without success. All of them leave ginormous scratches in the stone, except for lightning lap, however that lap moves so slowly that I rather not use it. I believe this is due to quality control. Does anybody have recommendations for a good topper lap and where you bought it. Below is the list of laps I've tried and how they rated. For consistency I've bought all of them at 3k then tried to polished the stone with a lighting lap 3k to bring out the scratches and remove most small shallow scratches that would be expected. for comparison my 3k crystallite lap leaves none.

Kent Supply Overall good however left two bands of very deep scratches (re-cutting on 1500 didnt remove them had do go all the way to 600 to remove
X-Cell Worst of all tested scratches everywhere
DuMin Didnt even test, was shipped rusted and had diamond compound splattered on reverse side
Kingsly north Best of the bunch but still left moderate scratches


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 Post subject: Re: Diamond topper lap/ review + questions
PostPosted: Wed May 16, 2018 8:37 pm 
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I think the typical recommendation is to never use a topper above 600 grit. For whatever reason they give poor results, particularly 3000 grit.

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 Post subject: Re: Diamond topper lap/ review + questions
PostPosted: Wed May 16, 2018 11:20 pm 
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I have never had good results from a topper in any grit 600 or above. In my opinion, the few dollars saved is not worth the aggravation of scratches, and runout issues. The Crystalite standard laps are very good and more than worth the cost considering that they last for years and cut many, many stones.


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 Post subject: Re: Diamond topper lap/ review + questions
PostPosted: Thu May 17, 2018 10:06 am 
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I have had negative experiences with any plated laps with grit finer than 600 US mesh and neutral with 600 mesh. If you cut many stones, a charged lap or a sintered lap are both efficient and economical.

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 Post subject: Re: Diamond topper lap/ review + questions
PostPosted: Thu May 17, 2018 5:58 pm 
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I have never encountered a 3000 plated that was satisfactory for very long. When new, they scratched from rogue grains. When they finally quieted down, they didn't scratch much. When, shortly after this stage, they wore out, they lost diamonds, which dragged across the facet. There seem to be physical size limits or metal/diamond ratios that don't work at plating 6µ.

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 Post subject: Re: Diamond topper lap/ review + questions
PostPosted: Thu May 17, 2018 8:48 pm 
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Joined: Sun Oct 29, 2006 11:43 pm
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Location: North Carolina
The toppers from Kingsley North, https://www.kingsleynorth.com are excellent. From my own use, that of many friends, and the many students at the faceting classes at North Carolina State University, toppers in 260, 600 and 1200 grit work great.

While some folks reject toppers without thought, all they have to do is look at a Crystalite Standard lap, which is (on those laps I have myself) a topper attached to a base plate. These have been around and well praised for years and years. So taking a topper and using it on a base plate (better known as a master lap) is pretty close to the same thing.

There ARE many BAD toppers out there. Once I saw laps at 500, 1000 and 2000 grit on ebay for about $10 apiece. Just to see their quality, I bought one of each. They look good and which is a coarser or finer grit is visible (good because they were not labeled). However, when I cut some facets with each grit, it was hard to see any difference between them. At 60x magnification the scratch sizes all looked the same. So I put them aside and warn students away from them. Could be they needed extensive breaking in? Don't know.

So, yes, some toppers are not worth much, though those toppers above did cut really fast. My experience with Kingsley North is that their laps, at $25 apiece, are a great buy and will last for more than 100 stones. Can't say how long because they haven't quit yet. Also, Lopaki toppers seem to work well but I have only a little experience with them.

In some ways I liken this to those who say not to ever buy a used machine. Personally, I've had hands on with over a dozen used Ultra Tecs (oldest was built in 1964) and 4-5 used Facetron's. Only two had problems: one Facetron had set in a humid basement for 20+ years and the lubrication in the head had hardened. I sent the head to Facetron and they cleaned it out and sent it back, working like new. The other was an older Ultra Tec where the adjustments to the yoke bearings had been turned as far as it would go and the yoke arms had spread open.

The NCSU Craft Center has 6 Facetrons from the 1980's which have been used mostly by newbies and people who thought they knew how to use them. Yet these used machines work just fine.

If a machine looks physically abused, yes, don't buy it.

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 Post subject: Re: Diamond topper lap/ review + questions
PostPosted: Sun May 20, 2018 9:24 pm 
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Bob K.
Hi. I have been professionally cutting colored stones since 1980 and diamonds since 1981. I have tried many different types of diamond laps in different grits on many different materials. Perhaps you have not been faceting for very long or perhaps you have not cut many materials. Hardness differences of minerals constitutes the major factor for cutting lap wear. Topaz is twice as hard as Quartz and Corundum is four times harder than Quartz, so cutting Corundum wears far more greatly on diamond laps than does Quartz. In actual practice, cutting Ruby and Sapphire wore out my plated laps very quickly and made plated diamond laps uneconomical for professional use. For that reason, I chose sintered diamond laps which you can redress as the diamond wears down.
If you're a hobbyist who cuts Quartz, Peridot, Sunstone, and Garnets, plated laps may satisfy your expectations. Where faceting of harder gem materials is a business, I have found plated laps to be much more costly than sintered diamond wheels when you calculate consumption and time costs.

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 Post subject: Re: Diamond topper lap/ review + questions
PostPosted: Wed May 23, 2018 1:48 pm 
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Recently I've started doing all my cutting after preforming with a 1200 topper and I love it. For some reason the 600 toppers that are available in bangkok are super coarse compared to what I'm use to as a 600 grit so I moved up to 1200 and it's great. Feels buttery smooth, cuts quickly, and doesn't seem to leave any deep scratches that cause problems in polishing. I go straight from a 1200 topper to a polishing lap with 0-2 or lately 0-1 diamond powder and olive oil and its giving me great and fast results.

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 Post subject: Re: Diamond topper lap/ review + questions
PostPosted: Wed May 23, 2018 10:49 pm 
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justinkprim wrote:
Recently I've started doing all my cutting after preforming with a 1200 topper and I love it. For some reason the 600 toppers that are available in bangkok are super coarse compared to what I'm use to as a 600 grit so I moved up to 1200 and it's great. Feels buttery smooth, cuts quickly, and doesn't seem to leave any deep scratches that cause problems in polishing. I go straight from a 1200 topper to a polishing lap with 0-2 or lately 0-1 diamond powder and olive oil and its giving me great and fast results.


Ah, you are learning so fast. You actually make most of your money preforming and doping, not laying the facets on.


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