For my initial rough in I use a sintered 1200 after a 180 sintered preform, if the gem is small I use the 1200 only to preform. My first real cut is done on Copper exclusively using free diamond grit to charge in Lucerin as a medium from a filled syringe, depending on the gem type this is anywhere between 3000 to 8000 diamond, I prefer 3000 as an all round and use it by far the most, I can still keep a real close eye on the facet "moving" and allows correction before its too late, but still gets through the 1200 scratches in good time, at the same time if you run too deep its a quick way to cover off previous facets to bring the stone back to square and meet. I pre-polish at 12000 again free diamond and exclusively on Copper. Polishing lap selection can be difficult I started with Copper exclusively but have progressed to a few in my selection now including Tin and also Batt alloy. I have not gotten too involved in all the fancy hoo-haa around the modern this and that of laps, green laps, red laps, split grit laps and the list goes on I think marketing can play too much a point in your lap selection if you let it. I stick to what works for me. I polish with 100,000 diamond free grit exclusively, I have used this since the very first gem I have cut. I use water as lubricant/cooling on the preform. I use refined odourless kerosene for the cut and polish, old habits die hard!!! I inspect every facet under loupe without exception as I cut.
Yeah a cheater, well I have one on the Ultra Tec and I tried it once..... and hated it, I learned to cut on a commercial Imahashi machine and taught myself, never had a cheater thingy, I learned to control lap position and hand pressure to achieve the same result. I guess I hate because I have simply never used it, my style had already been developed over decades and I find it easier without it.
In time your machine will talk to you as you cut, there is a distinctive sound made when your facet is flat and you will come to it when you are on the money, get it wrong and you will hear a horrible squeal or grind and a bright mark on your lap with my types anyway, and a perfect condition lap will now be a mess with a deep cut in its surface that has been gouged out.
For the above reason I also check whenever I change a lap/index or angle without power to the motor and turn the lap with a CLEAN washed hand, you will see under the loupe where the facet is cutting/lap touching in relation to the gem and it will let you know if you are plumb and square.
Above EVERYTHING else is cleanliness, use a clean paper towel every time you need one and for every lap or grit without exception, keep your hands clean and wash them at every lap change and touch nothing that you will contaminate or risk cross contamination with. Keep your machine looking like it has just been unwrapped from its factory packing. Every lap has its own assigned storage and clean your lap if necessary before use and before storage. Follow this and the headaches will be far less and it will save you money without doubt.
Sorry bout my essays on the topic, maybe I should write a book.
