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Burr speeds


#1

Could someone suggest appropriate burr speeds when cutting a seat
for setting diamonds in a Tiffany head either 4 or 6 prongs???

Thanks in advance
Ralph Cross


#2

Hello Ralph Cross, Well let me first say do not, I repeat do not,
let the burr run fast! Or you will have the burr jump around the
inside of the claw and ruin with little teeth marks and they will be
very difficult to clean up afterwards. Rule to ponder; if you can see
the teeth of the claws while its turning, its too slow,eh ! ! So the
correct burr speed is enough that a groove is being cut. 500-600
r.p.m. maximum! Not too slow as to pull the claw sideways, but
enough to actually make a bearing cut into the claw. I would make
sure that the bearing cutter is sharp and not worn. I use a H.S.S.
steel 45degree angled cutter. They burrs are the exact shape of the
diamond to be set. I usually start with a small budd burr # 006 to
act as a “bearing guide” . Ralph, another thing, is to have the burr
about 75% the size of the diamond. I usually “pull back” each claw
(just a tad!). This is to gain more accessability to each claw! Then
after the “cutting-drilling” is done, place the stone into these
claws, and pull them back into the regular shape and to hold the
stone. Cup burr the tops, ( “77 b”, cup-design) …gerry, the
cyber-setter! www.gemzdiamondsetting.com
sorry for details in setting, but it helps,eh?..gnl!


#3

As far as what speed to cut seats in prongs, for greater control use
a relatively slow speed. The bur should spin fast enough to avoid
catching but definitely not full blast. For greater precision, fine
tooth burs (not high speed steel) are easier to use.

Alan
Revere Academy of Jewelry Arts
760 Market Street - Suite 900
San Francisco, CA 94102
tel: 415-391-4179 fax: 415-391-7570


email: alan@revereacademy.com


#4

Alan, I definitely agree about using fine tooth burs. They are far
easier to control than high speed coarse tooth burs, and they can be
easily resharpened with a mild nitric acid dip. But I like to run
’em at high speed! I find that I have more control and I can use a
smaller bur…they just won’t grab when they’re running that fast. I
have to add, however, that it took me a while to learn how to do
this. It’s like riding a motorcycle over 100 mph…the first few
times will make you very nervous. Once you settle into it, it’s not
bad. It takes almost no pressure on the bur to cut a lot of metal.
You have to also learn never to slow down while you’re in contact
with the metal, or the bur will run all over the place.

Now, I have to remember to slow down when I’m teaching someone how
to use setting burs. I do not recommend this for anyone just
learning, but I do encourage people to increase their speed as their
skill increases. I’m sure that everyone has their own threshold
concerning speed. If you go too slowly, however, it is just as hard
to hold a bur steady as it is going too fast.

Happy setting,
Doug Zaruba


#5

Doug, I would like to paraphrase what you said and set it to music
regarding the challenge of speed, whether riding motorcycles or
setting stones. When you know where all the corners are, you can cut
them. But until you are confident, skillful and know the lay of the
land, follow Jerry Garcia’s advice to Casey Jones and, “Watch your
speed.”

Alan
Revere Academy of Jewelry Arts
760 Market Street
Suite 900
San Francisco, CA 94102
tel: 415-391-4179
fax: 415-391-7570


email: alan@revereacademy.com


#6

hi just in case anyone wants to control burr speeds very nicely with
your pedal, you get a speed control(transformer),at any jewelry
supply or machinist tool supply. you set them both in line
(flexshaft to speed control to pedal), set the speed control to a
speed and press the pedal. The burr will never go faster than the
speed set on the control,but you will get all speeds in between. so
you could set the control on 2 and get all speed between 0 and 2
with the pedal etc. or of course you could make a stop on your
pedal by putting a bolt in the housing or you could put different
thickness’s of wood or something in there so you can’t press too far.

As far as burrs go, like alan said,a fine burr is good on metal to
take off enough, but if a heavier cut is needed on metal,a carbide
crosscut burr(or high speed steel crosscut) will take off more
material more vigororously, with much more control than a standard
cut(mill cut). Aluminum oxide burrs are also very good for taking off
minute amounts(come in many shapes)

@David_Piccoli (email any time)