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Messages - FlashGP

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Very well.  Peter Stringfellow test cut it as my concave was still a concept at the time.  He cut a stone about 6 or 7mm.

Now I have my concave working I plan on cutting it in amythest after I finish a couple of stones I am cutting for my wife.  I can't enter the competition.

I added the concave facets on the pavillon to the design I cut my daughter in tormalike, a 10mm stone.  Her stone sparkles beutifully and I like the design in larger stones.

I hope you will enter, especially the 2 optional sections.  I would like to see them gain a little traction and invigorate the comp.


Gemstone Faceting / Re: MB concave build
« on: September 12, 2019, 05:43:07 PM »
Thanks Makky.

I have used both a stationary splash pan and one bolter to the oscillator.  The stationary one is better as I can rest my hank on it when cleaning swarf off the cutter and it does not continually flex the drain hose.  A piece of 6.35mm copper aircon return pipe soldered to the splash pan makes a nice  point to plug the drain into.

My first splash pan made from a piece of 2 inch copper pipe and fixed to the oscillator hit a large piece I was cutting parrallel concaves in when I was cutting the facets on a large rectangle (abt 3.5cm long)

Forum Announcements & Rules / AFG 2020 Faceting competition
« on: September 11, 2019, 08:49:52 PM »
Hi All,

After 12 months of work and anticipation, we presented the competition schedule for the Australian Facetors' Guild 2020 Annual Faceting Competition Schedule to the AFG's muster last weekend.

We are trying to expand interest in the competition and have included two optional sections in Open division.  Makky, you had better finish your concave cutter because we have included a pretty little concave cut design I made based on the Bar Round 1 cut.  It's actually a mixed concave, flat facet paillion designed to lift the brilliance of the stone.

The other new feature is what is becoming known as the Open Challenge.  We set a design based on a drawing I did of a stone cut by Ron Young.  The challenge is that the cutter has to create his or her own cutting diagram and instructions and submit them with the stone for judging.  20% of the marks are presented in relation to the cutting diagram. 

We had a couple of trial runs and made up our own judging sheet for the cutting diagram.  The sheet is different to the sheet for the international Challenge.  Check it out.

I am still waiting for the AFG Webmaster to post update the AFG Competitions page, he may still be travelling home from Casino.  Here's a link to the Competitions page if you wish to have a look at the schedule when it is posted.

In the meantime I have put a copy on my silver smithing web site.  Here's a link to that page.
I'll take it down a little while after the AFG site is updated.


Fossicking Locations / Re: Places to find radioactive rocks?
« on: September 11, 2019, 08:17:17 PM »
Hi Rej,
Keep this up and you'll have men in black suits with dark sunglasses and earpieces visiting you.


Gemstone Faceting / Re: MB concave build
« on: September 11, 2019, 08:12:19 PM »

How do you find the lower linear bearings on your cutter?  I wasn't sure if they would have more slop than the linear bearings that run on the round rods (like those in your carriage for the motor.

Is that a CNC cutting head motor attached to your collett?  If it is how do you find it?  John Broadfoot had suggested a CNC motor, but they were 400W, it seemed a bit of overkill that would require a second power supply for the remaining electronics.

If you lower where your oscillator assembly pivots for angles by 30mm, you would have room to undercut the base a little so you can get 90 degrees.  I'm looking at that for step cuts.  The theory being that they would increase the range of angles that the side facets would reflect at, increasing brightness of the cut. 

The added benefit of lowering the cutting head assembly, is that you can then get 0 to 90 on the Quill and have a little spare for big stones.  It may make fitting the splash tray easier.


Gemstone Faceting / Re: MB concave build
« on: September 11, 2019, 01:33:27 PM »
Hi Makky,

you can use bearing alloy, but brass works well.  I have a re-purposed tap spindle for one cutter.  The others are brass inserts over which annealed copper tube has been pressed and glued in place with Locktite 262.

Aussie Sapphire may have some Polymetric mandrels left with 3/th shanks.  They were too big for my ER11A collets (max 7mm, but should work with ER16A collets.

I'm also considering buing some 1/4 inch and 6mm brass rod from the local brass supplier.  It comes in 3.6m lengths.  I figured I could make the 1/4 rod into new dops and cutters, and the 6mm into thread for more accurate adjustment than the current threaded rods I am using that were designed for stepper motors.


For Sale or Swap / Re: Faceting Designs Book
« on: August 24, 2019, 09:49:46 AM »
Hi Andrew,

Good to hear your concave machine is coming along.  I am using a motor with a 5mm shaft and haven't run into trouble with flex in the shaft.  The end of my collet finishes only 1 or 2mm from where the shaft leaves the front bearing.  I think the bigger issue is perfectly centering the collet on the motor shaft.  I included a bit of a discussion on this in the article in the latest Facet Talk.

I am still experimenting with an extension shaft (150mm shaft with the collet mount machined as a single unit) mounted in a couple of bearings.  My first attempt was an abject failure, but I have since found that the shaft seems to run true at each end, but is not perfectly round in the middle.  Attempt 2 will be with the self centring pillow block bearings mounted at each end.  I tried the linear style bearings (which can also be used for a rotating shaft) but with the eccentricity of the shaft, these were not smooth enough.  A bearing mounted shaft introduces a fair amount of bearing noise, especially on my configuration of a plywood platform..

Anyway, I'm purchasing a second copy of your facet designs book for our lapidary club.  We have a fair number of new cutters and some decent designs would be great.  A lot of the old designs they have window badly.


For Sale or Swap / Re: Faceting Designs Book
« on: August 19, 2019, 11:09:20 PM »
Hi Andrew,

Congratulations on your book.  It is interesting to compare the effect of the pavillion facet shapes against the performance of the design.  The arrow shaped facets in many of your designs seem to be the key to a good performance across a wider range of tilt angles than the more traditional elongated diamond shaped mains facets in standard cuts.



For Sale or Swap / Re: Faceting Designs Book
« on: August 07, 2019, 07:54:36 AM »
Hi Andrew,

Oscillating Rotary Table?  Is that for your concave cutter?


For Sale or Swap / Re: Faceting Designs Book
« on: July 30, 2019, 06:24:11 PM »
Hi Andrew, you better half's and your health comes first  we can wait for a book.

Hope your better half has a speedy recovery and your tooth (or what's left of it) is feeling better.


For Sale or Swap / Re: Faceting Designs Book
« on: July 23, 2019, 06:06:51 PM »
Best of luck.  Tooth ache is never pleasant.

For Sale or Swap / Re: Faceting Designs Book
« on: July 17, 2019, 08:01:47 AM »
Hi Andrew,


How much to buy direct from the author?


Ask a "Silly" Question / Re: Moulding Gold
« on: June 25, 2019, 06:10:15 PM »
Hi Moth,

There are tables you can look up to give the ratios neede for the desired colour, yellow, rose, white (also the less common purple, green and black).  You would need ti get the quantities for 18ct and subtract them from 9ct to work out how much impurity to add to 1 oz of 18ct to make it 2 oz of 9ct.

If the percentages are the same, you could use gold alloying beads from AJS or A&E Metals to oncrease the dilution of the hold and turn 18ct into 9ct gold.  These beads are not gold, but an alloy which when added to pure gold makes the quantity of carat gold you want.  They usually also include deoxidising agents.

Gemstone Faceting / Re: TV glass toxicity?
« on: June 25, 2019, 07:59:31 AM »
Hi Makky,  the high lead glass should be the front of the screen, to protect the viewer from X radiation.

TV screens have tens of thousands of volts potential in them, the little 16 inch screens we ran in space invader mavhines ran at between 15000 and 25000 volts.  The bigger the screen, the higher the voltage.

When breaking a svreen, first earth one end of the probe to the chassis, then poke the business end under the rubber flange over the end of the HT lead where it meets the screen.  If the screen is live, it will discharge with a crack.  It is then safe to handle.

Remove the yoke, a good source of copper binding wire, and break the neck of the tube off with a hammer.  It is thin here and the safest place.  You can then saw up the tube with lapidary equipment, or a diamond blade on an angle grinder if you take precautions to avoid breathing the dust.


Gemstone Faceting / Re: Stepper motors Fantasy machines
« on: June 25, 2019, 07:50:30 AM »
Thanks Makky,

Do you know if they work by toggling each set of pins sequentially like with a flip flop, or or if the pulses overlap so rotation direction is controlled.

I am also looking to rotate my machine on a pivot under the centre of the cutting mandrel.  I just have to work out how to keep it stable as the top of my plattern pokes through the base plate and in operation clears my motor by 2mm.

However to fantasy cut using shaped wheels, you meed the motor at 90 degrees to the direction of oscillation. 

This means making the whole unit bigger so you can mount the motor pointing at you across the top of the pivot, or oscillating ths axis you usually use to allign the cutter to the centre of the C axis of the stone. 

Hence the stepper motor for the y axis.  It can serve both as a positioning servo and as an oscillator.

I am yet to get sn arduino, but would use one if I confugure with a stepper motor.  Then I can have a position readout, voltage monitor to check the motor health (my last speed controller was feeding up to about 180vdc to the 90vdc motor, no wonder it was humming like a centrafugr) and a taco for the lap.  If I had a need, also an angle readout for the quill.


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