I'd like to see a bur set, 45 or 90, cut with a profile designed
for "fat girdle" stones. They would look like regular setting burs,
except instead of a sharp edge, the edge would be squared slightly,
to cut a notch in a prong that would provide clearance for stones
with thicker girdles.
Dear David,
I was cleaning up old emails and found this entry and an answer
struck me.
Burrs for " fat girdle " stones could be made from regular setting
burrs by grinding or sanding the sharp edge away .
This will leave the edge squared slightly, but with the same 45 ,
70, or 90 degree outside profile. The upper and lower cutting edges
would remain sharp and at the same angle.
The amount ground off the outside edge would determine the
girdle thickness which would be left in the prong or side wall .
And perhaps by grinding a " safe edge " on the upper or lower
cutting edge of these burrs, you could also quickly manipulate which
part ( upper or lower ) of the seat which could be cut away.
In the past I have used # 8 cut escapement files and or gravers to
correct these problem. Slow - very slow .
This is another use for all the old bits which we all keep in hopes
of finding a use for.
I have several medium grit 1" x 3" diamond honing sticks. These are
used to clean up and deburr hard cutting tools. Cheep and works
great.
I am getting ready to begin moving soon, and I will not be able to
check this out . If it works out, some one please let me know as
cutting stone seats in prongs and walls is not easy .
ROBB - Still waiting for the other shoe to fall.
Robert, Making a 45 or 90 degree bur for a thick girdle is not a
setting solution. I rarely have encountered a stone with these
angle’s. The bur is used only to cut a seat for the stone, if these
burs are your choice instead of using a setting bur. After the seat
is cut you should file or sand the top of the prong back… this will
allow any size girdle to be set. Karel
Tools I’d like to see - revisited
Nicolaas, I have had to make compromises in my prong setting
techniques due to my having lost use of a finger and part of my thumb
on my right hand ( I am right handed ).
I have found several solutions to this shortcoming, none as fast as
coming straight down with a setting burr. If You can do it . I can’t
.
First I preset my prong alignment as normal and check for prong
height . I then cut with a 90 or 70 degree burr with a setting stop to
control depth . Rio Grande - “Stone Setting Stops” - $ 19.25 for 2 ,
3/32" dia. I have 4 total, two which are kept set with 90 degree
burrs ( large & small ). ( I need to remind myself to get 70 degree
burrs ). Depth is easy to set and maintain. - MOST HIGHLY RECOMMENDED
.
The outside of the prong is then cut back slightly and forced down.
The cup burr should be used before pushing the prong down. Then clean
up with an three sided escapement file with one safe side. Then a
fine silicone pumice stone lightly. Check Stone Hardness .
We were taught to set stones, first, on cast bronze heads we cast
ourselves. Cast heads can be hardened somewhat by burnishing with a
magnetic pin polisher and then by further burnishing with a pin on a
small mandrel. Then in fourth semester we moved up to store bought
heads in 14 K . Oh - Happy Day. We still cast and finished everything
else though.
Another use for these setting stops is when I am cutting a bezel
bottom for setting a cabochon in a cast setting. First file the
bezel top flat. Then use the flat top to maintain the cutting depth
with the setting stop. I have found an inverted cone burr is just the
ticket to cut the ledge. Then file or pumice stone the bezel outer
face. Solid . Use a Bench Mate with Jett Sett to support the inside
and hammer set.
I am slow because I am old . I am cranky because I have had much
practice . I am humble, because Crow has become part of my food group
.
< Grin >
ROBB.
Robert, I’m certainly sorry for the compromises you’ve had to make,
however I can’t tell you how many times I’ve seen stone setting done
with a 90 degree bur with a large v shaped cut next to the girdle…
Obviously by your description you have the knowledge…but lets be
honest… most jewelers leave that nasty little cut by the girdle,
and most do not polish the setting after the seats are cut… By the
way I use those depth gauge’s also, great little device. Karel