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Under Construction
by Bob's Rock Shop
Displayed at this year's Old Pueblo Lapidary Club Faceter's Hobnob was a special faceting machine which has been newly created to facet very large gemstones. The "Monster Faceting Machine" is the product of a collaboration between Old Pueblo Lapidary Club members Art Kavan, Billy Bob Riley and Tom Miller. Art is a former OPLC president, current president of the United States Faceters Guild, and is well known to the world class competition faceting community. Billy Bob is an OPLC lapidary and smithing instructor and faceter, and Tom Miller is a current OPLC board member. Billy Bob and Tom also happen to be machinists and fabricators.
Art Kavan provides some scale as he proudly poses with the Monster above left. An overview of the machine in place upon its sturdy cart is shown above right. The cart features retractable wheels on two legs - note the dolly used to engage and lift the other side standing just to the left of the cart. Art is the ramrod and financial benefactor of the Monster Faceting Machine project.
Shown at left twiddling the mast micrometer is Billy Bob Riley, who has provided all of the machine work on the faceting machine proper and who has also endowed the project with a fair amount of the raw material consumed in the making of the Monster from his personal stash of salvaged and surplus plate and bar stock. Tom Miller handled the fabrication of the cart and laps.
The above right view of the Monster's faceting head details the spring loaded index gear pawl engaging the gear teeth and the operation of the fractional index adjuster, also commonly referred to by faceters as an "index cheater". As the index cheater crank is turned slightly one way or the other, the gear pawl is laterally displaced by the rotation of a screw, facilitating incremental adjustments of the index position much finer than the 3.75° movement corresponding to a change of a single tooth on the 96 tooth index gear.
The overall general configuration of the Monster is known as a mast type faceting machine, this nomenclature being derived from the prominent mast used to position and support the faceting head and dop. The 33" high mast on this machine is fashioned from 1 3/8" stainless steel rod. The vertical position of the faceting head is coarsely changed by sliding it up or down on the mast and secured in place by tightening a screw driven d-clamp. Once clamped, a precision 40 thread per inch mechanical micrometer at the top of the mast (depicted at right) provides fine, calibrated adjustment of the head position over a 1" range of travel, Each full turn of this micrometer raises or lowers the head by .025".
The Monster operates as a "dead stop" type machine, which is to say the downward angular position of the faceting head and dop relative to the lap and hence the depth of cut are mechanically limited. Cutting by Ear provides a description of a time honored faceting technique using this general type of machine.
A side view of the faceting head is provided above left. The clevis attached, sliding stop rod serves to limit the angular travel of the head and dop. When the end of this stop rod's travel is reached as the head pivots downward, the mechanism arrives at its hard stop. I noted the machine design places this rod in compression rather than tension when it is supporting the weight of the head, dop and rough at the hard stop. This mass is considerable and I wondered if there might be potential flex issues with this rod. Now it is a pretty beefy rod, but then it needs to be, as weight of the rough alone this machine is capable of mounting and cutting could reach into the tens of kilograms...
The picture above right illustrates the construction of a dop and its attachment to the quill. Big stones require big dops! A transfer fixture of comparable scale has yet to be fabricated. Indexing is provided by a 6 inch diameter, 96 tooth gear. Nuts and bolts notwithstanding, this gear and the bearings are among the few across-the-counter components employed in the faceting head of the Monster not custom machined by Billy Bob.
Provided above are views of the protractor and detail on the 1/10° vernier used to set and adjust the elevation angle of the head and dop relative to the lap. I noted the calibration on the Monster's protractor extended well beyond the 0° to 90° range of travel calibrated on most faceting machines.
The faces of the cutting laps are fabricated from and covered both sides with 20" diameter disks cut from 1/8" thick copper sheet, which are attached to a core consisting of a 20" diameter steel disk cut from 1/2" thick steel plate. My calipers opened to 6" provide some scale for the mounted lap depicted above left. These laps alone weigh approximately 60 pounds each! They are constructed and attached to the motor driven platten in a manner that eliminates the use of the central bolt and nut protruding above the cutting surface of the lap typical of many faceting machines. This feature will facilitate working the stone over the full surface of the lap if so desired.
Depicted above right are details of the mast base and the dual "t" slots milled in the machine base plate that the mast assembly slides back and forth in. The 97 pound base plate is fabricated from a 24" wide by 36" long by
Depicted above are the Monster's massive 1-horsepower DC motor and speed controller, which were acquired as salvaged goods for $100. This is a 3600 rpm motor, so with the 2" pulley on the motor and 11" pulley on the arbor, the laps will turn with a theoretical unloaded top speed of about 650 rpm. At 650 rpm the edge of a 20" lap will be moving at approximately 40 mph, compared to approximately 15 mph for an 8" lap turning at the same rpm. That's all somewhat theoretical at this point however, as this motor and controller have yet to be wired and tested. So it isn't yet known at the time of writing if this motor even turns, but at $100 for the motor together with the controller, it was considered worth throwing the dice. Assuming the motor and controller work, their ability to drive under the load and braking effect of the friction and weight of the stone, head and dop bearing against a lap also remain to be proven.
Art distributed a hand-out providing some background regarding the impetus and his motivation to build the Monster and some further details about it.
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Why would anyone want a large faceting machine? A few reasons are that there are very few of them and our group is going to find out why. Another reason is that you need to keep stretching the perimeters in order to keep life interesting. And third there is a practical reason for museum and exhibition stones, not to dismiss the fun of doing it. I was first introduced to the Dare Devil's faceters work at the Faceter's Guild of Southern California Faceters Symposium 2000 which was held in Riverside California. There were several large stones on display and I was intrigued with the logistics of how they were made. I never thought very much of ever being involved in such a project though. Later in 2003 I was at the Ventura symposium and although there were no stones there, Ed Romack (a Dare Devil Faceter) was and I talked some about it there. In 2004 I was at a symposium in Mount Vernon, Washington and again talked with Ed Romack and he had a stone with him and we talked again about cutting large stones. Sometime in 2005 I decided to build a machine and experience cutting large stones. I got pictures of the Dare Devil machine and equipment and talked to Ed Romack a few more times and started talking to others and getting ideas. I got Billy Bob Riley and Tom Miller both machinists to help with the project and I did all the financing. Billy did the machine and Tom did the platform and laps. So here is what we have. The base plate weighs 97 pounds by itself, it is 1 1/4" thick, two feet wide and 3 feet long with double "T" slots to hold the 33 inch mast. The facet head looks like a tank turret with a 6" 96 index gear. We have 1" dops, a mechanical protractor for now, maybe digital in the future, a dead stop. The plenum is 9 1/2" with two wheel bearings. There is a one horse DC motor with variable speed to power it. We are still working on laps, we have they finished they are made out of 1/2" steel 20" in diameter with two 20" diameter 1/8" solid copper disks bonded on each side. We plan to use 100 diamond to start after using a chop saw to pre shape (notice I did not say pre-form) the large stone. We are working on corian 3/4 inch bonded on 3/8" aluminum to use oxides and one dished out and poured with black cabbing wax which will be charged with diamond for polish. You have to see the Monster to appreciate it. |
When I asked Art how much longer it would be until he was ready to cut a big one, he replied that the machine is now otherwise ready to run as soon as the motor is wired and proven. When I inquired what would be cut first, Art responded that he has a 10 kilogram or so piece of clear quartz on hand that may be used for a first pass at proving and debugging the Monster if there are substantive delays in procuring a suitably large piece of cubic zirconia.
Art and the Tucson group are following the footsteps of the Dare Devil Faceters, a venerable and celebrated group of Northwestern faceters with the motto "The Bigger the Better". Among the Dare Devils was Ed Romack, along with Richard Glismann, Calvin Miller, Dallas Hales, Carl Unruh and Cliff Jackson. The remarkable accomplishments of the Dare Devils group included the 7,597 carat Lucky Stone CZ, the 3,444 carat Duchess Quartz, the 12,678 carat Countess CZ and the 5,280 carat Milestone Citrine Quartz, which are depicted in my report on the Faceter's Guild of Southern California Faceters Symposium 2000.
Art credits several discussions with Ed Romack as instrumental in interesting him in cutting large stones and getting him started on the Monster. Ed is also well known to competition faceters, having served as a judge to numerous competitions including a number of Australian Challenges. I noted Ed was present at the 2006 OPLC Faceters Hobnob and actively engaged in discussing the Monster and the faceting of large stones with Art and other faceters gathered about it as I photographed the machine and interviewed Art and Billy Bob. Billy Bob has volunteered to field further questions regarding the Monster and can be emailed at stonefaceter@yahoo.com or phoned at (520) 408-3074.
Of course there is no doubt a significant curve ahead of Art and the Tucson group as they set about learning the ins and outs of operating the Monster and begin to facet large stones. My understanding is the Monster is significantly larger in capacity than the Dare Devil's own custom built machine, and so theoretically at least, should be capable of working even larger stones. If they apply the same determination, dedication, effort and love of faceting to the cutting of large stones that has propelled Art to the top rank of competition faceters, the fruits of their labors should be interesting and spectacular indeed.
Depicted above is the interior view of the meeting room in the Old Pueblo Lapidary Club clubhouse as the tables begin to fill with faceters and significant others here for the OPLC Faceter's Hobnob, held this year on Saturday evening, Feb 4th. This annual event is held during the Tucson Show and serves as the primary gathering and social event for amateur faceters attending the Show. I noted over 70 signatures on the guest register for OPLC's 2006 Faceter's Hobnob. The Hobnob provides a great opportunity to socialize and meet other faceters face to face. Many of the Hobnob attendees have previously become acquainted online and shared questions and answers through the USFG Faceters Email List.
A most beautiful gemstone contest has been traditionally held during the Hobnob to provide an opportunity for the attendees to show off their work along with receiving bragging rights and an award plaque if their stone wins. No meetpoint judging here, the stones are seat-of-the-pants evaluated by the contest judges based on their overall effect and presence, or "beauty". The entries were divided into two divisions, one for natural stones and one for man-made materials. A panel of judges for this year's contest was selected from among the Hobnob attendees at random.
Above left is an overview of the 13 stones entered in the man-made division. The most beautiful of these was judged to be OPLC faceter Paul Head's 16.5 mm cubic zirconia heart, depicted above right. Paul's original design stone was cut from a very pale aqua CZ. Paul said this stone took him about 10 hours to cut. He couldn't recall the weight of it off the top of his head.
Above left is an overview of the 16 stones entered in the natural division. The most beautiful of these was judged to be Andrei Brodzik's 11.5 x 7.5 mm Afgani tourmaline oval, depicted above right. This stone employs a barion oval design, Jeff Graham's "Rainbow". Andrei related that he has been faceting for only two years and that he has probably cut less than two dozen stones total to date. Andrei estimated it took him approximately 6 hours to cut this stone. Andrei has just recently moved to Tucson and we are looking forward to welcoming this relative newcomer and promising faceter to Old Pueblo Lapidary Club.
Depicted above two "effect" stones entered in the contest that depict a butterfly and a spider. Above left is a butterfly rendered in natural clear quartz. The designer of the butterfly cut and the faceter who cut this stone are both unknown to me. Above right is a spider rendered in a 53 mm synthetic clear quartz. This stone employs a reversed frosting variation of my Bola Spider design and was cut by fellow OPLC club member and Monster machinist Billy Bob Riley. Billy Bob most likely holds the world record for faceting the most Bola Spiders, reputedly having cut approximately fifty of them to date.
If you are a faceter or interested in faceting and don't yet have a copy of the OPLC Faceters Companion CD, be sure and check it out.
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