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Drilling Dilema


#1

I am attempting to drill through some vintage square cut nails I
have been collecting.

I am using a small drill press, lots of “bur life”… and still I am
having the worst time! I have tried diamond tip drills, carbide steel
drills… I have gotten all the way through a couple of them. With
the carbide drill the drill wanted to break just as I was going
through the far side of the nail. At this rate I am going through one
drill bit/nail. There has got to be a better way!

The nails are only about 1/8 inch thick and perhaps 1/4 inch wide. I
am using.55mm drill bits.

Suggestions? Thoughts? Ideas?

jeff
Jennifer “jeff” Bowie


#2

Sounds like your vintage nails are common cement nails which would
be hardened. And a real pia to drill. They would look like ole timey
nails but are made for going in to cement, brick,block and concrete.

You could try annealing a couple and see if that would help you.
That is a small dia hole and with out the proper combo of speed and
lube and down ward pressure sometimes it is one hole/one drill and
resharpen the broken bit.

If the hole was a larger size dia they do sell a solid carbide drill
bits for drilling in hard steel. Most any tool die machine shop
supply would have them.

glen
been there done that !


#3

What is your drill press speed? Very small bits like that need
speeds that are way beyond most drill presses. I would want at least
5000 rpm for that small a bit. The item being drilled must be held as
rigidly as possible so clamp the nail in a vise and make sure the
vise is clamped to the drill press table. Also you need to "peck"
drill when doing deep hole drilling (deep drilling is more than 3
times the drill bit diameter), to peck drill bring the bit into
contact with the work briefly then lift it all the way clear of the
work, repeat. This aids in keeping the hole clear of chips that
cause binding of the bit which will break it. As you have observed
the highest stress operation in drilling is breaking through the back
side of the work. Take it slow remember to peck and get as high a
speed as you can for the bit. Seriously 10,000 rpm would not be too
high for that small a bit.

James Binnion
@James_Binnion
James Binnion Metal Arts


360-756-6550


#4

“Jeff”, Perhaps the square nail should be annealled before
drilling?

Suzanne Cassidy


#5

Those old square cut nails are hardened steel wall nails designed
for hammering into brick walls.

To anneal (remove the hardness of) the nails, heat them to bright
red hot and let them cool down as slowly as possible. As they are
small items they will cool quite quickly in air, but even so will be
soft enough to drill. To cool them more slowly, thus annealing them
more, bury them in wood ashes immediately while they are red hot and
remove after about 5 minutes.


#6

Jeff,

Try using a center punch to make an indentation on the surface that
will keep the drill bit from skating off the desired location for the
hole. Then use a center drill to start the hole. Switch to the 0.55mm
drill bit using light pecks to drill through the nail. If the nail is
held secure, and the drill press runs true, then you won’t break
nearly as many drill bits.

I use high speed steel drill bits for just about everything but
rock. I’m too clumsy for the carbide tools.

HTH
Another Jeff


#7

I presume these are iron nails. If so then use an ordinary high speed
steel drill bit designed for drilling metal. Almost any lubricant
will do, even water. HSS drills have the advantage that they have
some flexibility but you will need to mark a centre to stop the drill
wandering when you start. For the diameter of bit you are using a
speed of 2000 rpm will suffice. Faster is OK but tends to not cut as
well if you go too quickly. If you still have problems then the rake
of the cutting edge will need changing to suit the material and drill
speed better.

Nick


#8

Hi Jeff,

I am attempting to drill through some vintage square cut nails I
have been collecting. 

These nails have been hardened and need to be annealed before you
drill them. There are several ways to anneal them.

If you have a kiln, or access to a kiln, heat the nail to
approximately 1400 degrees Farenheidt, then let it cool at the rate
of 36 F per hour. It will be annealed and will drill easily. This
will take approximately 40 hours, but it will give the greatest
softness.

If you don’t have a kiln, use a bucket of kitty litter, or a bucket
of sand, heat the nail to cherry red, then put it in the sand to
cool. It helps if you have the sand hot before putting the nail in
it. The annealing process is better the longer it takes the steel to
cool.

If you plan on using the nail later as a nail, harden it by heating
it red hot, then drop it in water. It will be brittle, but hard.
After you have hardened it, it will be necessary to temper it.

To temper it, buff a portion of the nail so you can see the shiny
steel. Put the nail in the oven at 400 degrees for an hour, it
should turn straw color where it was buffed. The colors go from
light yellow to brown to blue as you raise the temperature. I make
Native American stamps, and my oven turns them yellow at 400
degrees, and blue at 475 degrees. You will have to experiment for
your oven settings.

Love and God Bless
randy
http://www.rocksmyth.com


#9

Hi Jeff,

There are probably two main things you are doing wrong - using too
high a speed and using too much pressure. Presumably the nails are
made of iron which is a soft and sticky material. Diamond drills are
hopeless with such materials and should be reserved for really hard
materials - glass, hard tool steel, stones etc. Either normal High
Speed Steel drills (not so called because you should use them at high
speed but rather because they can tolerate higher speeds than the
older tool steel drills without losing their temper) or carbide
drills shouod work Ok. If you are using High Speed drills, you should
use a fairly low rotation speed - maybe around 6 - 800 rpm and drill
with just enough pressure so that the drill keeps making chips. you
should ease off the pressure every few seconds also to clear the tip
of the drill and cool it a little. If you are using carbide, you can
use a higher speed but, again, only enough pressure to make it cut
and lift off regularly. Also with carbide, it is important that the
work is held down firmly (as in clamped) to the drill table as the
drill will almost certainly break if the work lifts as the drill
breaks through. In both cases, you need to ease off the pressure to a
large extent as the drill starts to break through as this is when the
drill is most likely to break. If you maintain the same pressure, the
drill will try to eat through the metal quicker as the hole appears
and the metal at the edge of the hole will jam in the drill flutes
and stop it. Of course, the drilling machine has too much power to be
stopped so easily and so will just break the drill. Using a lubricant
in this situation is optional - its only purpose would be to cool the
drill and, if you drill in little bites as I suggest, this will not
be necessary.

Best wishes,
Ian
Ian W. Wright
Sheffield UK


#10
If the hole was a larger size dia they do sell a solid carbide
drill 

There’s pretty much anything one wants in the world— There are
solid carbide drill bits going down to less than #80 size. As Jim
said in another post, RPM’s are probably the problem - and they
probably are masonry nails (try to bend one, see if it snaps). With
wire size solid carbide drill bits, it’s required to have a high
speed precision drill press. They are like potato chips, and any
deviation will snap them instantly. They’re really not an option
without the right drill press. They’re easily found on ebay for a
lot cheaper than retail, but I’m warning you — they are literally
like egg shells.

http://www.donivanandmaggiora.com


#11
For the diameter of bit you are using a speed of 2000 rpm will
suffice. Faster is OK but tends to not cut as well if you go too
quickly. 

That is too slow. Slow rpm leads to too much load on the drill and
drill breakage. The recommended speed for a low alloy or basic
carbon steel like these hardened nails is between 50 and 130 surface
feet per min (15-40 meters/min). RPM = Surface Ft/min x 12 divided by
drill diameter in inches x 3.14 (RPM = Surface m/min x 1000 divided
by drill diameter in mm x 3.14) So the recommended speed of a 0.5 mm
drill bit is 9549-24828 RPM ! Of course you can drill at much lower
speeds but the likelihood of breakage goes up with greater deviation
from recommended speeds and feeds.

Most jewelry alloys are going to be towards the higher end of this
RPM range, and beyond up to 200 surface feet per min.

This kind of is found in machining texts like
Machineries Handbook which I find very useful but I found a good
chart for drill speeds on the net at

http://www.tapdie.com/html/drills_guide.html

I am sure there are others out there as well.

Jim

James Binnion
@James_Binnion
James Binnion Metal Arts


360-756-6550


#12

With a correctly sharpened HS drill bit, plenty of lubricant (don’t
smoke it), low speed (again don’t let it smoke and soften the drill
bit), and steady pressure, you can drill almost any iron or steel.
I’ve even been asked to drill out broken crank pins and frozen
hardened bolts, and a watchmaker I have worked with regularly drills
hard stainless with his HS bits and an oil he gets from Rolex as his
lubricant.


#13
I am using a small drill press, I am using.55mm drill bits. 

This is a tough one, James hit the “nail on the head” with his
response, but more importantly (annealed or not) the runout on your
drill press coupled with manual control and the size of bit, will
make this difficult for any one. I would re-evaluate the need for
such a small bit and possibly go up in size to reduce the breakage.

As for futher advice, I would start off with a centering drill to
get the center punch made, move to a solid carbide drill for a
majority of the work, then switch to a hss bit to punch thru the back
side. If you can keep the nail submerged in water or a light oil
while you do the drilling, that will help out tons, and keep that
nail secure.

30 days with no internet…im finally back.
P@
www.patpruitt.com


#14
the drill wanted to break just as I was going through the far side
of the nail 

What I have found useful is to back the piece being drilled with
another fairly hard surface. As to drill speed…whether you like it
slow or fast its helpful to speed up when you near the end of the
hole.

Half a millimeter is a small drill, if you can find a way to use a
larger diameter that will surely help too.


#15

In your case, using solid carbide vs. HS vs. carbide tipped drill
bits is not as important as other concerns. As previously mentioned,
most important is to ensure that the workpiece and drill head are
firmly clamped and immobile relative to each other (except for
vertical movement of the drill head, of course). Any lateral
movement will cause breakage.

Drill tip deflection is a source of many problems, including bit
breakage. We mount a fixed bushing between the drill head and the
workpiece (very close or touching the workpiece) that guides the bit
and prevents deflection. Not only is entry point deflection
eliminated, but this helps prevent deflection inside the drilled
hole when the bit encounters a hard spot, micro-porosity, etc. The
suggestion to use drill pecking is important to remove the chips
produced by drilling. In pecking, the benefit of chip removal is
equally important to the benefit of cooling the tool. During
pecking, the bushing also helps guide the bit consistently.
Regarding the use of coolants, a stream of water on the workpiece
during drilling not only cools the bit, but also flushes away chips.

Finally, annealing first may actually contribute to bit breakage.
Soft iron allows bits to cut easily, and the last much longer
(hundreds or thousands of cuts). However, that same softness can
contribute to “binding” during the cut and ultimately breaks the
bit. On the other hand, bits wear out much faster when cutting
hardened iron (sometimes after only a hundred cuts) but many other
cutting problems are avoided.

Good Luck,

Jamie
Ohio


#16

I find that the slower speed means that the flutes cut a decent
spiral of metal. I do drill at much higher speeds in different
metals but that is dependant upon the hardness of the metal and the
rake of the bit. Sometimes the quoted surface speeds dont match the
work. An example being drilling 22k gold, almost impossible to drill
at high speed because the metal clogs the bit almost instantly.
Changing the rake improves things but I find an old fashioned
archemidian drill works best at low speed (0.5-1mm dia hole). Goes
against intuition. Otherwise I have the advantage of being able to
spark erode hard and awkward holes-I once got asked to drill some
ball beadrings for a sculpture so it was the only practical way.

Nick


#17

Most sources such as manufacturers websites, machinery handbook etc.
say that you should use small drills at high speed but this data is
only really relevant where the drills are used in precision
industrial machinery for drilling shallow holes and with bags of
coolant. In practice in a small workshop slower is better and,
indeed, very slow might be best. Any hole which is more than 3 times
the drill diameter is classed as ‘deep drilling’ and is a different
ball game to normal drilling as factors such as chip removal, side
friction, difficulty of cooling the drill tip etc. come into play. I
regularly drill holes down to 0.1mm diameter through carbon tool
steel in making parts for watches and so I have, over the years,
tried every combination of speed, pressure, coolant etc. Trying to
use a high speed with a High Speed Steel drill or a Carbon steel one
will just blunt and glaze the point very quickly. The temptation (or
one could almost say ‘reflex’) then is to increase the drilling
pressure to make the drill cut which then, inevitably, causes the
drill to break. If this is in iron or steel you then have the
almighty and often insurmountable problem of trying to remove the
broken pieces from the hole. In brass or similar metals this is not
too bad a problem as you can dissolve the broken drill away by
soaking it in an alum solution for a few days. Carbide drills, on the
other hand, do need quite a high speed - though not as high as
usually quoted for the same reasons as above, but they need a very
light pressure or they will quickly dig in and snap. The only way I
have found to remove them is to try to break them up with a little
punch - not easy at small sizes and often still leaves debris
impacted in the hole which prevents further drilling. In any case,
an accurate drill press is needed for such small drills and drilling
should be done by ‘pecking’ gently at the hole with the drill
running at a fairly low speed - patience is the key!! Coolant is
optional but, in a deep hole, can cause the chips to clog together
and sieze the drill into the hole - I prefer to work dry and blow the
chips away with an air jet. An alternative way to produce the holes
may be to make a simple spark eroder - there are several plans on the
web for making such a machine.

Best wishes,
Ian
Ian W. Wright
Sheffield UK