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Stone setting bur getting dull


#1

Hello, I am a begginer at silversmithing (self teaching) and have a
question on doing tube settings. I have succesfully done about 6
tube setting so far but i’m sure I must be doing something wrong
because I dulled about 3 setting burs in the process. Hmmm yeah not a
very good ratio is it? I have heard that it’s better to go in with a
ball bur first to cut the seat down a bit, then follow it with a
setting bur, so I have ordered some. However, I have read tutorials
that show it being done with nothing more than a setting bur. To
answer some questions you might have, I am using bur life lubricant,
and setting burs from rio grande. I just feel so sad that I ruined
those burs and finally decided i’d better join ganoksin because my
questions are getting far beyond anything I can find by searching
online. Also for future reference, how long should a bur last?

Jessica


#2

Jessica,

If you have thick-wall tube, you need to hog-out the metal before
finishing your hole with a setting bur. Start with one or more bud
burs (the fat type, not the long, skinny type), and then clean-up
with your setting bur. To keep your burs sharp, use lubricant and
don’t take too much metal with each cut before moving up to the next
size bur.

Good luck,
Jamie


#3

Jessica -

Along with what Jamie recommended, run your flex shaft at a slower
speed when you are doing this. I ruined drills and burs early on
because of too high a speed. Even with lubrication they overheated &
lost their temper. Now I use a lighter foot, better burs and cut a
little at a time.

Good luck to you,
Kelley


#4

It is possible to dull a bur in seconds if it is run at too high a
speed, so that it overheats, even with lubrication. Slow even
cutting, keeping the lubricant from burning away is the secret.
Having a low speed, high torque setting flex shaft does help in
keeping the speed and heat down, but good control of rhe shaft speed
is the key what ever set up you are using.

I have burs that are several years old and still sharp, while I have
a box of burs that died because I rushed a bit too much. I do not
toss the damaged burs, but keep them to make other tools. small
punches, burnishers, etc.


#5
To keep your burs sharp, use lubricant and don't take too much
metal with each cut before moving up to the next size bur. 

I would add to this that most novices spin their burs and drill bits
way too fast. This generates enough heat to ruin the temper of a
steel tool and dull it very quickly. Keep your speed low to moderate.

Also, FWIW, I hate Bur Life-- it strikes me as crumbly, doesn’t
stick to the steel. I bought a bottle of thread cutting oil at the
hardware store. I keep a tiny container with a cotton ball soaked in
oil next to the flex shaft & just dab my burs on that. Just make sure
the bur isn’t spinning when it touches the cotton!

Noel


#6

It has been my experience that burrs will dull at high speeds. I
don’t dull the burrs but I do dull a lot of drill bits - I tend to
get impatient and go too fast!

Judith Keller
http://www.judithkellerdesigns.com


#7

Jessica,

Hello, I am a begginer at silversmithing (self teaching) and have
a question on doing tube settings. I have succesfully done about 6
tube setting so far but i'm sure I must be doing something wrong
because I dulled about 3 setting burs in the process. 

They sell even really good burrs in 6 packs for a reason, they are a
tool with a finite life. HSS ones sold in fancy wood boxes tend to
fair better but you tend to treat then more gently due to the
purchase $$ I have a drawer of spare 6 packs, a diamond setter I
once worked for had 10X as many, and a good tool supplier only a few
floors down.

How fast a speed and what pressure? Little teeth tend to cut slow
with a gentle feed. Don’t get them hot. (blue is really really bad)
Without abuse they last a long time, although they do get dull with
lots of use. The rust demon in my shop probably kills more than I
do.

jeffD
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.gmavt.net/~jdemand


#8
I would add to this that most novices spin their burs and drill
bits way too fast. This generates enough heat to ruin the temper
of a steel tool and dull it very quickly. Keep your speed low to
moderate. 

I’m relatively new to working in fine metals - but have quite a bit
of experience working with ferrous metals in a tool shop. One of the
early mysteries to me was the matter of tool speed - and just how
inadequate foot pedal speed control can be - most especially in the
use of burrs, drill bits and other cutting tools. My first move was
to buy a benchtop speed control unit from the same folks who made my
flexshaft unit and use it in combination with a foot pedal switch for
on/off. This provided some of the desired flexibility. However, I
soon found that I wanted to also control the speeds at which my drill
press, polishing motor and a variable speed drill unit which I use to
wind coils operate. (I tend to make many tools from salvaged/surplus
parts). The little speed control unit couldn’t handle the amperages
needed, so I have since gone to a Baldor DC motor control which
solves the problem nicely. Now when I need to use a power tool, I
simply dial in an appropriate motor speed before putting it to use.

I’m sure that many old timers can simply step on the pedal and adjust
the desired speed of a tool to what is wanted by its sound - but this
has worked well for me.

Jim