Edited and updated from my post to Jerry Dewbre’s Faceting Digest, 2000 Dec 31st.
Originally in response to John Schuy’s request for experiences with loose diamond grit mixed with Teflon Super-Lube grease for cutting and polishing.

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I am a commercial cutter and my needs are dictated by my customers which makes for a different attitude than most cutters. I do NOT recommend any of my methods for new or beginning faceters.

I don’t know whether this is a particular brand of Teflon grease but I have tried a locally available one, I have also tried silicone grease, graphite grease(filthy), molybdenum-disulphide grease and Vaseline as well as many varied oils and waxes. Although I do have to admit the differences between the various lubricants were not significant enough to make anything I tried stand out as superior. What is significant is that everything out-performed water by leaps and bounds. All produced more aggressive cutting with considerably better staying power for the diamonds and a more predictable action.

What makes water lub’ed cutting attractive is that it’s clean, has no smell, has no unpleasant feel and it wipes off easily from a facet and also when it gets on you. None of the grease, oil or wax lube’s can compare well with any of those features, so it comes down to whatever is the least offensive to the style and sensibilities of the individual cutter.

When using oil for lubrication there is no flushing action as the amount of oil used is minimal,  a drop or two is usually sufficient. This makes for a build up of dirty oily swarf  that is unpleasant but it does allow rapid cutting even more so if you dual grit your laps. Deliberate contamination Yikes! I dual grit some of my copper laps with a narrow ring of coarser grit at the perimeter. Cut and pre-polish without lap changing, A polishing lap with a pre-polishing ring lets you cut small facets and polish with the same lap. I have a BATTWing and also a tin/iron lap that were purposely built for dual use.

Whether loose, bonded or sintered, you will find that a new lap loses it’s aggression after a stone or two and then settles down after a few more. With sintered and bonded laps you live with it and call it the ‘break-in’ period, in fact many users will often prepare these laps by vigorously sweeping them with synthetic corundum before using the diminished ‘broken-in’ lap for cutting. These laps will now perform for many hundreds of stones without any noticeable change in performance. Obviously self-charged laps will ‘go off’ first, whereas well cared for plated laps have cut thousands without slowing down. Sintered laps by their very nature should last a lifetime.

Some cutters prefer the action of a freshly charged lap and will wastefully often re-charge to keep a lap as sharp as possible. The premise being that the cutting time saved represents considerable greater value than the excessive diamond use. I would be one of them.

With a grease/oil/diamond slurry you can set up a lap and use this effect to control your cutting aggression.  A ‘reservoir’ of slurry around the centre of the lap for an aggressive action to a slower action at the outer rim. This is very useful in a pre-polishing lap, especially if your meets need coaxing in a few places.

I use diamonds quite liberally and I do not use the traditional method of embedding. Certainly more wasteful, I just tap out little piles and smooth them around with an oily finger tip and then let the cutting action do the embedding. A new lap in a couple of seconds! I know I could probably reduce my diamond costs by using traditional charging methods, amounts and frequencies, but my bench time is the bottom line that is nicely accommodated with getting sharp/fast laps instantly.

With a sharp lap, corundum has a hardly noticeable hard and soft direction, most everything you cut is going to be predictable, consistent and fast, also high lap speeds are not necessary for rapid material removal. It is considered S.O.P. to clean a stone and wash ones hands before polishing but it is particularly important with greasy or oily fingers which hang on to contamination so much better.

Oil can be used for polishing too, my first choice being a BATT lap with an oil/diamond polish, it’s also what works best with zinc. I also have found that oil holds both Ce-Ox and Al-Ox very well on tin but not that effective on plastic. I have never used oil, grease or wax on a Darkside lap and see no reason to try

I must point out that use of an oil/grease lubrication when cutting is not practical for any stone that has cracks or veils that will reach the surface of the stone as they will surely fill with cutting swarf making an ugly black stain inside the stone that is nigh impossible to remove. Another related problem is that oily fingers can remove the printing from diamond boart bottles. A colour coding inside the bottle cap prevents mystery grit.

Tony.

The most obvious updates to this 10 year old article are the references to my use of Jon Rolfe’s innovative polishing products.
One of his latest products is his answer to the search for the least offensive way to enjoy the benefits of an appropriate lubrication. Once again he produced a winner.

CLICK HERE TO GET YOURS

CLICK HERE TO GET YOURS