The argument over 100th being used, is all about the lap tolerances and pressure, I use a weight for constant pressure and I don't press down on the stone on the lap; then the tolerance of the lap matters. I use ceramic laps for the cutting, of course I am cutting a circular shape, so the min amount of normal force is pressed back to the quill. I can facet to the 100th under this condition, but I admit I am to making flat facets. The argument of you cannot facet to 100th of a degree, depends on the amount of time your willing to cut the stone. In a commercial environment and using and pressing different pressures, you cannot, the only case, is the case that I use to cut circular objects and apply a constant force on the quill by using a weight that Ultratech provided. I use the DAD V5 UltraTech machine, the same as the given example with a uneven lap, I am only cutting the stone using a portion of the lap to maintain the 100th tolerances. For commercial uses and procedures, yes the different pressure will drop tolerances, as your lap is not that flat. However I have a AlO2 Lap that is flat, but I don't have a way to actually measure across the lap, yet.
Fascinating. Your report has me really interested in some things: What are the materials you are working with? What kind of work are you doing that requires precision to one-hundredth of a degree of angle? How are you achieving sufficiently flat lap surfaces that lap flutter isn’t creating more than one-hundredth of a degree variance? What kind of polish are you using so that the polishing medium itself isn’t causing variance? How much time does it take you to produce such precision? What kind of instrumentation are you using to measure the finished results, and validate that you are producing the angles to within one-hundredth of a degree? Based on your use of instrumentation to measure the actual finished results of your efforts, what is the range of tolerance you typically achieve? Thank you again for sharing your own experiences, and for filling-in some of these details.
When I first started faceting using a Graves Mk 1 machine, I saw designs with those 100ths which I called "Goofy Angles". Those designs were very intimidating to me UNTIL I got Gem Cut Studio which helped me better understand the significance (or insignificance) of those 100ths of a degree. I learned to set my Vernier as close to a repeatable position as possible and then closed in the Meet Points by raising or lowering the mast via Fine Height Adjustment Only to cut more or less on the Heel or Toe of a Facet. It took a while but I soon overcame my fear of "Goofy Angles" ! 😁
It’s incredible that you are achieving, holding, and repeating to 1/100th of a degree on any machine, especially a Graves. Please share the kinds of materials you are doing this with, and the time required to achieve it. Please share what equipment you are using to measure the finished product to know that you are actually achieving precision to the indicated 1/100th of a degree?
Very useful information for new faceters as myself.
That's exactly why I went for the analog dial instead of digital reader and saved myself hundreds of dollars.
I agree. Is one reason I try to round off in my designs.
The argument over 100th being used, is all about the lap tolerances and pressure, I use a weight for constant pressure and I don't press down on the stone on the lap; then the tolerance of the lap matters. I use ceramic laps for the cutting, of course I am cutting a circular shape, so the min amount of normal force is pressed back to the quill. I can facet to the 100th under this condition, but I admit I am to making flat facets. The argument of you cannot facet to 100th of a degree, depends on the amount of time your willing to cut the stone. In a commercial environment and using and pressing different pressures, you cannot, the only case, is the case that I use to cut circular objects and apply a constant force on the quill by using a weight that Ultratech provided. I use the DAD V5 UltraTech machine, the same as the given example with a uneven lap, I am only cutting the stone using a portion of the lap to maintain the 100th tolerances. For commercial uses and procedures, yes the different pressure will drop tolerances, as your lap is not that flat. However I have a AlO2 Lap that is flat, but I don't have a way to actually measure across the lap, yet.
Fascinating.
Your report has me really interested in some things:
What are the materials you are working with?
What kind of work are you doing that requires precision to one-hundredth of a degree of angle?
How are you achieving sufficiently flat lap surfaces that lap flutter isn’t creating more than one-hundredth of a degree variance?
What kind of polish are you using so that the polishing medium itself isn’t causing variance?
How much time does it take you to produce such precision?
What kind of instrumentation are you using to measure the finished results, and validate that you are producing the angles to within one-hundredth of a degree?
Based on your use of instrumentation to measure the actual finished results of your efforts, what is the range of tolerance you typically achieve?
Thank you again for sharing your own experiences, and for filling-in some of these details.
When I first started faceting using a Graves Mk 1 machine, I saw designs with those 100ths which I called "Goofy Angles". Those designs were very intimidating to me UNTIL I got Gem Cut Studio which helped me better understand the significance (or insignificance) of those 100ths of a degree. I learned to set my Vernier as close to a repeatable position as possible and then closed in the Meet Points by raising or lowering the mast via Fine Height Adjustment Only to cut more or less on the Heel or Toe of a Facet.
It took a while but I soon overcame my fear of "Goofy Angles" ! 😁
It’s incredible that you are achieving, holding, and repeating to 1/100th of a degree on any machine, especially a Graves.
Please share the kinds of materials you are doing this with, and the time required to achieve it.
Please share what equipment you are using to measure the finished product to know that you are actually achieving precision to the indicated 1/100th of a degree?
Hi,very thanks