N
notbob
Guest
On 2013-03-07, Danny D. <danny@pleasedontemail.com> wrote:
group.
As an ex machinist, here's the drill (sorry-couldn't resist):
You need a HSS drill bit (high speed steel). If you can't see the
letters HSS somewhere on that drill, it's not and yer wasting your
money. Make sure the drill bit is sharp! Brand new is even better.
You need a cutting fluid. A specialized cutting fluid is best, but
clean motor oil will do, like the kind you put in yer car or lawmower.
Have a squirt bottle or oil can full on hand and keep that drill bit
WET! The cutting fluid is as much about keeping the drill bit cool as
it is in aiding cutting action.
Use the proper drill motor "speeds" (RPM) and "feeds" for the material and
drill size. Generally, the smaller the hole diameter and drill size,
the higher the drilling speed (RPMs).
http://members.home.nl/b.ollivier/html/drillspeedchart.htm
Drilling "feed" is how fast the drill bit is plunged or pushed into
the work. Some drill presses have an automatic feed which you can
set, but usually it's jes experience and judgement that dictates how
hard to feed. I see you have a drill press. This is GOOD!, as
stainless steel (SS) is difficult to drill with a hand drill motor.
The trick to drilling SS is to keep the feed pressure firm and
constant. Once you start the hole, do not reduce pressure or "get a
better grip" on the drill press handles while the bit is still
spinning in the hole. Back it out and start again. Once in, constant
presssure. You may see some smoke from the fluid. That's can be a
good sign and an indiction to add more fluid. You should see chips
ejected out of the hole. Smoke and no chips means you are not
cutting, but "work hardening". Keep adding fluid to the hole/drill
while cutting to keep it cool and the chips ejecting. Add fluid with
left hand while right hand works the drill press handle. Light
colored chips (yel, org, red) are good. Shows good pressure. VERY
DARK blue or purple chips means you are pushing too hard (feed too
fast) and you will prematurely dull your drill bit.
If you see no chips ejecting from the hole, you are not cutting and
are now "work hardening" the SS. Bad mojo! If SS work hardens, yer
screwed. It becomes almost impossible do go past that point. You
will hafta buy a carbide drill. Not titanium coated or any of that
crap. Go straight to carbide. If you hafta go to carbide, NEVER stop
the drill motor with drill in the hole or while drilling/cutting. It
will break that carbide bit instantly, gar-own-tee!
And yes!! DO use a center punch to make a starting point. It will
NOT work harden the SS. Work hardening is caused by the heat
generated from the drill friction. That's why you don't want yer
drill getting hot. Keep that sucker douched!
nb
A lotta bad advice from this group. You shoulda asked a metal working
group.
As an ex machinist, here's the drill (sorry-couldn't resist):
You need a HSS drill bit (high speed steel). If you can't see the
letters HSS somewhere on that drill, it's not and yer wasting your
money. Make sure the drill bit is sharp! Brand new is even better.
You need a cutting fluid. A specialized cutting fluid is best, but
clean motor oil will do, like the kind you put in yer car or lawmower.
Have a squirt bottle or oil can full on hand and keep that drill bit
WET! The cutting fluid is as much about keeping the drill bit cool as
it is in aiding cutting action.
Use the proper drill motor "speeds" (RPM) and "feeds" for the material and
drill size. Generally, the smaller the hole diameter and drill size,
the higher the drilling speed (RPMs).
http://members.home.nl/b.ollivier/html/drillspeedchart.htm
Drilling "feed" is how fast the drill bit is plunged or pushed into
the work. Some drill presses have an automatic feed which you can
set, but usually it's jes experience and judgement that dictates how
hard to feed. I see you have a drill press. This is GOOD!, as
stainless steel (SS) is difficult to drill with a hand drill motor.
The trick to drilling SS is to keep the feed pressure firm and
constant. Once you start the hole, do not reduce pressure or "get a
better grip" on the drill press handles while the bit is still
spinning in the hole. Back it out and start again. Once in, constant
presssure. You may see some smoke from the fluid. That's can be a
good sign and an indiction to add more fluid. You should see chips
ejected out of the hole. Smoke and no chips means you are not
cutting, but "work hardening". Keep adding fluid to the hole/drill
while cutting to keep it cool and the chips ejecting. Add fluid with
left hand while right hand works the drill press handle. Light
colored chips (yel, org, red) are good. Shows good pressure. VERY
DARK blue or purple chips means you are pushing too hard (feed too
fast) and you will prematurely dull your drill bit.
If you see no chips ejecting from the hole, you are not cutting and
are now "work hardening" the SS. Bad mojo! If SS work hardens, yer
screwed. It becomes almost impossible do go past that point. You
will hafta buy a carbide drill. Not titanium coated or any of that
crap. Go straight to carbide. If you hafta go to carbide, NEVER stop
the drill motor with drill in the hole or while drilling/cutting. It
will break that carbide bit instantly, gar-own-tee!
And yes!! DO use a center punch to make a starting point. It will
NOT work harden the SS. Work hardening is caused by the heat
generated from the drill friction. That's why you don't want yer
drill getting hot. Keep that sucker douched!
nb