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Author Topic: Cabs from a faceting machine  (Read 3091 times)

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Shifter55

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Cabs from a faceting machine
« on: July 31, 2019, 11:17:23 PM »

A month ago I decided to make my own cabbing disks after the club I went to replaced their soft drums with harder versions. Was simple to do, just a neoprene foam disk and some good SiC sandpaper, had some issue choosing glues... but settled on stationary glue sticks for how weak they are.

I don't have a polish pad yet so the finish only goes up to 8K grit, but it's enough to make light material shine nicely, and the softness allows for very smooth curves!

Here's a 17x11mm cab that was taken from the orange core of some white mozambiquan agate, pictures were taken on a mirror to show the clarity of this stuff. With the leftover white material I might carve something to flank it with...

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rocks2dust

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Re: Cabs from a faceting machine
« Reply #1 on: August 01, 2019, 08:00:32 AM »

Looks great!
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Shifter55

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Re: Cabs from a faceting machine
« Reply #2 on: August 24, 2019, 02:03:23 AM »

Here's some more cabochons, it seems my large grit disks are wearing out quickly, so maybe it's time to upgrade to the fabric they use for belt sanders...

Bronzite from Australia. This stuff doesn't seem like it's straight amphibolite, since there's chalcedony and ironstone concretions running through it. Has some impressive spangles when you rock it, but since I cut this cabochon upside-down they are concentrated at the girdle.

Botswana Agate. Was hoping this would show some parralax effects when it was done, but the transparent zones are too cloudy for anything like that, it's a nice pink however.

Black Chatoyant Sunstone from Tanzania. The eye from the fibers was kind of over-exposing my camera when taking this shot. It's also an adularescent material so you can see a weak blue secondary eye on the right from that phenomena filtering through the fiber. I also have a backlit image to show off the inclusions and transparency, would you believe that in pieces with sparser inclusions you can get decent light return in a faceted stone?
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Shifter55

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Re: Cabs from a faceting machine
« Reply #3 on: January 14, 2020, 09:40:34 PM »

More stuff, going from left to right: Mozambique agate, Sunjade prehnite, Quebec hypersthene, Montana agate, and Indian hessonite. The prehnite also shows a star as seen in the attached video.

Anyone have advice for cabbing the harder black hypersthenes? The cleavage and lamellar structure means I get fissures when I go off the sheen axis, and it's getting to the point where I'm considering sodiom silicate treatment for the whole lot just to get it to behave.
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Shifter55

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Re: Cabs from a faceting machine
« Reply #4 on: April 19, 2020, 07:28:49 PM »

A piece of mt. Hays thunder egg with red specks, for some reason the dome on this stone tends to pick up light easily, resulting in a glowing tan cabochon...

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vitzitziltecpatl

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Re: Cabs from a faceting machine
« Reply #5 on: April 20, 2020, 07:35:03 AM »

Nice cabs. Nice material you're working with, too.

Noticed the bottom edge of the girdle on the Botswana was still sharp and chippy. Do you bevel that edge intersection after you're all done with the polish? Some people wait until then. I like to bevel them after I'm satisfied with the shape and girdle angle at the 220 stage.

Shifter55

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Re: Cabs from a faceting machine
« Reply #6 on: April 20, 2020, 11:27:46 AM »

Thank you Vitzitziltecpatl, that cab is the only one here that didn't have a bevel put on it.

With the darker material I've been putting the bevel on first to give a more obvious border, but I think I'm going to avoid doing it on cabs with L/Ws higher than 1.75, due to needing a little more care on the sharp ends.
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Shifter55

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Re: Cabs from a faceting machine
« Reply #7 on: August 26, 2020, 11:15:58 PM »


It's finally warm and still enough to cab outside without hurting my hands, so here's some more turkish blue and a test cab of pakistani idocrase.
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ileney

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Re: Cabs from a faceting machine
« Reply #8 on: August 27, 2020, 08:35:27 PM »

Beautiful stones. You got a very nice polish on the Turkish blue! The glow is quite pretty.
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Shifter55

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Re: Cabs from a faceting machine
« Reply #9 on: August 27, 2020, 09:38:59 PM »

Beautiful stones. You got a very nice polish on the Turkish blue! The glow is quite pretty.
Thank you, it helps a bit that it's under 20mm in length, the backing foam isn't quite resistant enough to truely cut at 8k if the cab is particularly large.
You can easily read text through slabs of the Turkish chalcedony, it's transparent enough that sometimes the Tyndall effect will wash out the blue from reflected light.
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Shifter55

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Re: Cabs from a faceting machine
« Reply #10 on: September 13, 2020, 12:16:20 AM »


This week's [successful, bloody hypersthene...] lineup. Pink tourmaline, Mtorolite, and Australian agate.

Girdle is a little thick, but the shape is good for catching light and followed the rough.

This was some Agate Creek material that I picked up because of some mud staining, the stained area cuts very differently and had cavities in it, also smelt like an ashtray so maybe not doing that again...
At least the shape came out well, was a test for a new stroking movement meant for tall cabs with extremely high L/W ratios.
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ileney

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Re: Cabs from a faceting machine
« Reply #11 on: September 13, 2020, 11:03:52 AM »

Weird. I love agate Creek stuff but mine has no smell and looks nothing like that!
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Shifter55

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Re: Cabs from a faceting machine
« Reply #12 on: March 19, 2021, 10:15:36 PM »

Had to get a new machine, old one had the bearing mounts failing, and there wasn't much that could be done there.

Here's a new material from Cambodia, I've only been able to get 100 carat-sized pieces but the combination of white banding and pink inclusions has an interesting effect.
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Shifter55

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Re: Cabs from a faceting machine
« Reply #13 on: April 11, 2021, 12:49:31 AM »







Some more cabs on my new machine. I tried a teardrop shape for the first time, couldn't really get good coverage on the straight areas, I think I'll curve the point a bit more next time.

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Shifter55

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Re: Cabs from a faceting machine
« Reply #14 on: May 15, 2021, 06:28:25 PM »


Some of the last of my silver obsidian and a droplet of purple smithsonite from a friday session. I wish I could capture the colour of the obsidan better on camera, it's mostly a beautiful silver grey like brushed steel without any green.
Smithsonite was sold to me as quartz, but I knew better. It cuts extremely fast and on the 8k polish stage I was even getting a "licked" effect from it being so soft.
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vitzitziltecpatl

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Re: Cabs from a faceting machine
« Reply #15 on: May 15, 2021, 09:14:14 PM »

Good work there. You obviously know what you're doing, and sound like you have no problem figuring out how to deal with the problems you've encountered so far.

It's a pleasure to see the material you're cutting, and the way you approach it.

Shifter55

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Re: Cabs from a faceting machine
« Reply #16 on: May 16, 2021, 12:13:54 AM »

Good work there. You obviously know what you're doing, and sound like you have no problem figuring out how to deal with the problems you've encountered so far.

It's a pleasure to see the material you're cutting, and the way you approach it.
Thank you, I still need to get over my reluctance to go with some of the in-depth solutions. Need to figure out a good way to do a final polish with a tumbler, and a durable design for a new style of cabbing lap that should solve my sandpaper quality issues.
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southerly

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Re: Cabs from a faceting machine
« Reply #17 on: May 29, 2021, 03:18:25 AM »

Nice work, great smooth curves. Nice to see some gem material cabbed.

David
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Shifter55

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Re: Cabs from a faceting machine
« Reply #18 on: June 05, 2021, 11:49:08 PM »


Montana Carnelian, this is much more river rounded and stained than the yellow, flat like it came from a rind too, and some Imperial jasper. That tuff is pretty adsorbent, going to have to watch for that when painting preforms to see flat areas.
How has everyone been going? I've mostly been fighting a post-lockdown-lift cold that the family commuter brought in, and winter joint issues.
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ileney

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Re: Cabs from a faceting machine
« Reply #19 on: August 01, 2021, 07:59:00 PM »

Beautiful. The purple smithsonite is especially lovely!
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