My drill is garbage

Jewelry Discussion
21

I was surprised and delighted to find that a little bit of practice
and an over-sized model enabled me to regrind my broken bits to cut
beautifully: I use a fine stone in the flexshaft for the first cut
(the basic point) and then a diamond cutoff wheel for the tricky
parts. It was very difficult to get the angles at first, as I am
doing mailnly 0.5mm (~0.019") drill bits. The trick was to use a
new, big fat drill (~1/2") as my model. That made it very easy to
’see’ the proper angles and set them in my head. As soon as I used
the big one as my guide, the little ones started coming out very
well. Before studying the big one, it wasn’t working so well. The
new skill saved me much time and money over the years as well as
being very satisfying!

Janet in Jerusalem

22

I have found that it is easy to sharpen drill bits by hand. I do It
quickly, as if to ‘touch up’ the edge rather than change it much.
After a bit has been touched up five or six times with a diamond
cutoff wheel, I throw it in a box with other bits that will need more
work to restore. If I break a bit with any length remaining, I save
it to restore later. I buy good bits and have five or six of each of
the three or four sizes I use most often.

Every once in a while, for example when I cannot find the size I
need, I will spend some time restoring the tips on several bits a
time.

I have not found that ‘drill sharpening’ machines are worthwhile.
However, newer ones may be much better. I had a jig that attached to
my bench grinder that worked well for medium size bits (around 1/4
inch), but it was too much work to set up the bit in the device. It
did not handle the smaller bits very well at all. I do have a really
good tool rest on my bench grinder. I find that the standard rests
are very near useless. I have the top of one rest set up just to hold
drill bits. It works very well to work out the point, but I usually
do the final sharpening with a cutoff wheel.

I like Janet’s idea of using an over-sized model. Once you know what
you want when you are finished, the process is a little easier. Also,
the cost of learning is fairly low. Most of the bits you sharpen will
be useful, even if they are not as good a new.

Komowkwa

23

I would suggest that you;

  1. Use a new drill.
  2. Get a cutting fluid called Tap Magic from a tool supplier
  3. More speed and less feed. Don’t push so hard.
  4. Use pilot holes with a smaller drill size.

Jim

Jim Zimmerman
Alpine Custom Jewellers & Repair

24 
have found that it is easy to sharpen drill bits by hand. I do It
quickly, as if to 'touch up' the edge rather than change it much.
After a bit has been touched up five or six times with a
diamond......

Commercial drill bits, everyday bits, that is, are made to a common
denominator. They are a trade-off between sharpness and durability,
and usually are “general purpose”. When I resharpen my bits for
jewelry (I have jewelry drills, milling machine drills, hand drill
drills, tap drills, carbide drills…) I make them sharper than
new. I steepen the angle, both of the point and the edge, because they
are for gold and silver almost always. That configuration would
quickly break the edges in steel. Very useful skill, drill
sharpening. I also do not care for jigs or machines (a $15,000 tool
sharpener is another animal, however)

25
  1. Use a new drill.
  2. Get a cutting fluid called Tap Magic from a tool supplier
  3. More speed and less feed. Don’t push so hard.
  4. Use pilot holes with a smaller drill size.

Industrial Distributor (Day Job) hat on now…

I can augment Jim’s excellent comments…

  1. Use a new drill.

Use the best drill bit available to you. Don’t go for cheap. This is
jewelry that’s being made, I’m assuming…no reason to skimp on
your tool… Most time one is drilling precious metal…so…

I use a power drill mounted in one of those “drill press” adapters,
hooked up to a lamp dimmer for speed control…most times the
dimmer is set to max on, because I’m drilling only small holes,
anyway so I want maximum speed…

I shot a 5/64 (.078 or 1.98mm) hole through a piece of brass over
the weekend, that I swear you could use for gauging the size…yes,
I’ve modified the adapter, because it had too much slop…and squared
it… Standard Cleveland jobber drill bit…the black oxide
kind…118 degree point…

Non oxide (the silver shiney ones) bits are often used in
non-ferrous (non steel) production…

The bright gold colored drillbits…TIN (titanium nitride) bits are
not only pretty, but a dream to use… TIN gives the bit not only its
own lubricity, but a surface hardness which makes it last longer…

Besides…a set of them looks like jewelry itself…

Note: many of the TIN drill bits are 135 degree pointed… These
will deal with gold and or silver, but the design is typically for
harder metals… Like steel and stainless steel… If you can find
118 degree TIN coat, will work better with the golds and silvers…

  1. Get a cutting fluid called Tap Magic from a tool supplier

Tap Magic is good stuff…there are many others… Most cutting
fluids are optimal for ferrous metals… Most of jewelry is
non-ferrous… It shouldn’t be an issue in most cases…But Rapid
Tap, for example, has a separate fluid for aluminum, which it reacts
with…

Many fluids don’t care what metal they’re used with in most
cases… Ask your supplier…

  1. More speed and less feed. Don’t push so hard.

Most of the time I’m shooting smaller holes…so I keep the bit
humming max (only 2500 RPM)… You’ll know when you hit the right
amount of push (aka feed)… Things start working…you’ll see
the chips magically appearing…almost spouting out…That’s when
you’ve hit the right mediums…so…keep it there…

There’s a kind of “sweet spot” for every size of drill bit and metal
it’s drilling… And it’s a “power band” or range that you can
find…most times…by varying speed and feed… For small holes, I
max speed, and then adjust the feed (push)…

Doing the old in and out thing doesn’t hurt also…that gets the
crud out of the way from the hole you’re trying to make…

This does not apply to stainless a lot of the time, because some
stainless steels work harden on you…so if you don’t come in
right, right away…you’ll dull the bit… And won’t have a hole… I
know sterling work hardens, but I’ve never had a problem in dealing
with it with a high speed drill bit…

If you wind up learning how to sharpen a drill…You’ll find you
can customize them for yourself and your metals… As sombody else
pointed out…a standard drill bit (118 degree point) is a
compromise…that’s why it’s called a “jobber” drill… If you make
the point kinda pointier, that is a less angle than 118, it will like
cutting silver and gold better… On the other hand…the standard
jobber will work well…

  1. Use pilot holes with a smaller drill size.

I’ll be honest…for smaller holes I’ve never used a pilot
hole… Only on bigger stuff…and not very often… The reason
is…you do have to be lined up on the money for that second
shot… And it’s harder to do with little holes…

I do use a center punch…I have a bunch of sizes, but the idea is
to coerce the drill bit into its starting place…by marking the
place… Be gentle with gold and silver…it’s not like whacking
away at steel… Buy a range of center punches…you can also use them
for texturing effects, if you have a mind to…good tool steel, so
you can make other stuff out of them, as well…

In case anyone is interested in my lamp dimmer-gimcrack drill press
setup…I do not recommmend it to anyone…I only use mine
occasionally, anyway… I did have to modify it with shims, threaded
rod and connector nuts…

I had this 5/16 thick wall piece of cold roll steel square tubing
(4" per side) I was shooting a #7 (.201) size hole though so I could
tap it for 1/4-20… Slower speed via the dimmer, got the feed right,
lotsa of Rapid Tap squirting, and nice, curly chips coming out…

It broke through, and I had no backing behind it, as it was this top
section of tubing… It grabbed on breakthrough… First the house
lights dimmed, then the power drill went up in smoke, and then the
dimmer did… Actually it’s hard to say whether the dimmer went
first, or the power drill… But the lights dimmed first…I remember
that…

Seems some…maybe most, motors when jammed, keep on sucking power
to try to finish what they’re doing until something gives…usually
the circuit breaker…

Both dimmer and power drill were toast… I was able to file out
the hole and tap it…

So…these days, again, I don’t recommend that kind of setup to
anyone…

Neighbor has a nice monster drill press I can put that kind of thing
on in the future… Or I’ll have him do it…we’ll split a beer or
two, figuring how to give the top some backing…

'Course, I haven’t had to shoot any #7 holes through sterling or
gold of late…

One of these days I’ll get one of those Proxxon drill presses…

Regards…
Industrial Distributor Hat off…

Gary W. Bourbonais
A.J.P. (GIA)