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                    – Add a New Dimension to your Faceting


                                  * Note: The Unit above is shown with a V2 Digital Faceting Mast. The Concave Faceting Machine does not include a mast


Concave faceting will raise your level of interest and excitement -- It creates “WOW!” stones.

Concave faceting “ain’t for kids”—it’s for someone who has experienced gem faceting and feels moved to the further enhancement of his gems.  Starting out with a faceted stone done on your Ultra Tec Faceting Machine, your Mast is then moved and positioned onto the Concave Machine—and aligned to the radial tool for the setting and polishing of the concave facets.

Yes, weight is lost—so it is an unlikely technique to be applied to expensive materials, rubies and emeralds, but, concave faceting is a way of making more common and less expensive gem rough—often varieties of Quartz — into objects of enhanced beauty and brilliance— and enhanced value.  And in any material, it provides enhanced satisfaction for the faceter who expresses creativity and skill.

 Yes, it takes time, and thought  - and gradually gained experience – and it takes equipment that can provide set-up ease, precision and repeatability, with controls of speeds and micro-adjustments.





-- This is the key element -- alignment of the faceted stone to the tool is critical. 


Initial Alignment

Initial Alignment (and realignment, if that becomes necessary) of a “home position” is quickly and directly performed by using the supplied Alignment Block.  The Alignment Block keys directly to the tool-holding Spindle—little room for error.


Tweaking the alignment   

The Mast-mounting Block provides “fine-tuning” stone position -- analogous to the “cheater” on the Faceting Machine. The Block provides for both radial and lateral micro-adjusting.


 Maintaining Quill Alignment 

Once aligned, the Quill, which swings from side-to-side in its flat-faceting mode, needs to hold steady.  This is accomplished with  the supplied Rigidizer.  It stops the side-to-side motion without inhibiting vertical setting or other functions.  It is fast-mounting—– less than a minute--and later, fast de-mounting.




Two motion elements are involved—there is the Tool Drive that provides tool rotation, and there is the Table Drive that provides tool reciprocation. Importantly, independent motors and speed controls for these two elements are provided. In general, high rotation speeds and high reciprocation speeds are beneficial.

Safe-voltage 12 V DC/PM Motors are covered by protective housings.

The sturdy reciprocation table rides a smooth dual-track linear bearing system.




Cylindrical Tools --  Three basic tool sets are provided – Copper, and Phenolic, and Maple of  8 mm, 13 mm and 17 mm diameters

The provided Adapters hold standard tool shank diameters for the many 'off-the-shelf' tools available from Ultra Tec or other companies: 3/8”, ¼”, 1/8”, and 3/32”. 





The Concave Machine can be upgraded to include some, or even all, of the features of the FANTASY MACHINE. For example, the dial-in X positioning with dial-indicator readout, can be added as a kit (that would allow you to work with ball-tipped tools). Other features would require factory installation – but this upgrading capability became a design consideration when we realized that many people would be faced with a decision—Cavity or Fantasy?—and with a bit of thought, we could make that an easier choice to make.
Making Concave Gems is pretty straight forward. There is a level of creativity involved—judgments to make—but everyone who has some faceting experience will rather quickly succeed. If you Google “Concave Gems”, the Internet will provide many accomplishable ideas—it’s still pretty close to your old friend, faceting. In Fantasy cutting, the level of challenge goes up, the need for creativity increases—of course, the number of things you can do increases. Google “Fantasy Gems”, and you will be provided with ideas all right, but much of your own “inspiration” is still needed. Where Concave cutting is a brother of faceting, Fantasy cutting is a cousin – a second cousin –closer to carving.

Things to think about !?

Our other new machine, the FANTASY MACHINE, can also operate in the Concave Mode – With the FANTASY MACHINE, siginificant capability is added, none removed. 

If you opt for a Concave Machine, and want to upgrade to the Fantasy Machine later – how much more would it cost than getting the Fantasy machine in the first place?  Not so much—perhaps $200.

Concave cutting takes more time than flat faceting, obviously – and fantasy cutting much longer.  In both cases, thinking time is involved – whereas in flat faceting you move quickly from one step to the next.  So— this 'ain't for kids' —and not for someone who lacks patience or time — but is certainly for someone who wants to broaden the horizon of lapidary interest.



The Concave Machine, ready to facet with your Ultra Tec V2 or V5 Mast (Rigidizer supplied)

Item number 2627.7


  - Click here for a range of useful products that extend the use of our equipment


>> This page last updated Feb 1, 2011



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