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Good prices on good drill bits


#1

Hello,

I’ve got a design that calls for drilling holes in a 5mm thick piece
of square sterling silver wire. Just trying to drill a few simple
holes with a flex shaft. I’ve gone from cheapo to mid-priced to
expensive drill bits and they are all breaking while no holes are
being drilled. I’ve decided it can’t be the drill bits and that it
must be me. Anyone have any tips as in what techniques I should be
using and what types of drill bits? I use bur life and although not a
100% sure its necessary, I’ve annealed the chunk of wire a couple
times too.

Any good sources for good prices on good bits?

Thanks,
Chris


#2

Chris,

I've annealed the chunk of wire a couple times too. 

In November 2009, there was an Orchid thread entitled “Drilling
holes through sterling silver rod.” There was a lot of good info in
that thread. By the way, I prefer to drill into hardened silver and
gold. I find that the annealed metal wants to “tear” instead of
cutting cleanly. I don’t have any citations to support this, just my
personal opinion.

Good luck,
JamieK


#3

Hi Chris,

You didn’t say what size hole you’re trying to drill into your 5mm
square wire. 1mm holes are different than 4mm holes, you see…

Meanwhile, for drills, I usually get short “screw machine” drills
from MSC. (www.mscdirect.com) They’re shorter than normal jobber’s
length drills, which means they’re more rigid, and less prone to
snapping. They’re plenty long enough for the things we use them for.

For very small holes (sub 1mm), it’s best to use a drill press. (or
a DP jig for a flex shaft.) It’s very easy to tilt your hand, or tilt
the work piece, or otherwise get the drill out of perfect
concentricity with the axis of the hole. Once that happens, the drill
snaps almost instantly. The little guys haven’t got any strength to
resist flexing, so they just snap.

Regards,
Brian Meek.


#4

Brian,

Thanks for the info. I’m trying to drill different sized holes,
mostly 1mm to 3mm.

Best,
Chris


#5

Your problem is most likely not with the bits that you are using,
but the tool. Anything hand-held while drilling, especially with
small diameter bits, will be too unstable. Machinists use sensitive
drill presses with small bits, such as those made by Dumore. However,
since you are drilling into very soft metal, you may be able to use
your flex shaft, if you buy a drill press set-up for it.

Here’s an example:
http://www.ottofrei.com/store/product.php?productid=5482

Fred


#6

Be sure to anneal the wire before trying to drill, and make a
starting spot with a center punch. This will help keep the drill
from slipping off the wire.

John
Indiana


#7

Whatever you are drilling the drill needs some sort of lubrication.
The little drills heat up much faster than the bigger ones, when
they heat up they grab and you know the rest.