3 years, 6 months ago-
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If you have a a machine with just a protractor and not digital, what do you do if the diagram calls for angles like 21.63 or similar?
Hi,
A digital protractor from your local hardware is the cheapest option. They have a magnetic base, so you could glue a metal strip to the top of your quill base for it to sit on.
They work well with a dial gauge as you can rest the stone on the lap. Adjust the mast height till you have the angle you want, take the protractor off, note the dial gauge setting and start cutting. Using the dial gauge as a stop you will be able to maintain that angle with that row of facets.
The protractors from your hardware are accurate to about 0.2deg, the one in the picture, which I got from eBay, is more expensive and claim an accuracy of 0.05deg.Regards,
Frank.Having exact angles is nice on a machine but is not absolutely necessary. With experience using the machine you have you can achieve the meets correctly. For example, those that repair gemstones have to find the angle of a facet to re cut or polish it without having any knowledge of what angle it was cut at. What I am saying is you do not need to spend $5000 or more for a machine to enjoy our hobby. I presently own a graves mk4, older ultra-tec, and a facetron. All are capable of cutting complicated designs.
David,
I am in complete agreement with you. I also own a Graves mk4 an a Facetron and have used each to cut complicated designs with success. One can enjoy our hobby on either machine, as do I.I have only used a facetron and the way I deal with the 100ths is to take the 10ths number imagine lines using .05 as the center base line. After finding the middle of each number a good reference point can be achieved to find .025 and .075. Like what was stated earlier, getting that close is all about the meet from there. But I can return to a previous facet to finish polish with out any issues or any fault of accuracy in the return to a facet for REWORK–hate rework
For angles like 21.63 I would put half way between 21 and 22. Do the same with all 21.63 angles. If it’s more or less than .63 (21.25, 21.75) just move just off the main line for 21 or 22 and use same next time you have that angle.
All one has to do is use your fine height adjustment to find to right angle to make your meet. One thing that bothered me when I bought my new Facetron concerning the new digital heads is that all electronic devices eventual fail. Decade old Facetrons still work great and command a high price. I chose to go with a good analog machine. I started with a new Graves and cut too many stones to count using most all Jeff Grahams designs with it. Protractor machines have been around like forever and have stood the test of time. Admittedly the Facetron is easier and quicker but for over double the price.
hey mike the guys are right… i have about 30 machines, 6 different models of the LEE, a graves mark 1, 2 O’Brien portables, 3 different yrs MDR’s, 5 diff ultra tec’s, 4 diff raytech/shaws,3 sapphires, facetron, and homemades. and parts. everyone seems to think the machine does the cutting—-NO—- you do, the machine holds the stone and has the cutting surface but its up to you to know how far to cut and where and this is the process in the learning. one thing a 10th of a degree is not noticeable by the human eye and the brilliance of the stone. i’ve told my students as long as you are close to to the correct angle but they all don’t meet BUT you have the best possible polish the stone will be eye catching. i have a cut— reverse brilliant you might like to try. simple same number of facets as the regular brilliant but WAY MORE flashy. if you’d like a copy of it and a piece of laser yag to cut to it give me a yell, gemmakermz@cs.com . i’ve had other u.s.f.g. members all over country trying it. and are happy with it.
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