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FAQ: Stainless Steel Drilling
How do I Drill holes in Stainless Steel and or Aluminum?
Stainless Steel Drilling
?
For Aluminum, see 2/3 down
this page!
Original Message:
I am changing my traveler bar and this means I have to drill new holes in
the Stainless Steel Plate just below the fiberglass where the traveler
mounts. How do I drill Stainless? Drill Bit? Drill Speed? Lubrication? Any
experts out there?
Capt Al, #55 C34, "Kindred Spirit", http://kindred-spirit.net
Subj: Re: Stainless Steel Drilling?
I know from experience a normal (even expensive) bit will not drill
stainless steel. You will need a carbide tip drill bit. I know you want to
keep the temp down on the steel so lots of cutting oil many breaks if you
are drilling thick stuff, etc. Not sure of what speed to use.
Richard, r_clack@hotmail.com
Subj: RE: [C34] Stainless Steel Drilling?
I've done this. The plate embedded in the 'towers' is not stainless,
it's either brass or bronze (at least on my boat, #52, 1986). As with any
metal, a little cutting oil doesn't hurt. Just about any bit rated for
metal cutting will do as long as it's sharp.
Bob Mack, "Upon A Star" #52, Bob.Mack@Compaq.com
Subj: RE: Stainless Steel ?
Stainless steel is a pain to drill, but it helps if you follow the
tips I've learned from experts. Get hold of some cobalt bits; expensive,
but worthwhile. Ordinary HSS (High Sped Steel) bits will dull too quickly
if used for stainless. Also, obtain some cutting oil; do NOT be tempted to
use WD40, the experts tell me that it 'runs away' from the hole as the
work heats up. Start with a small-than-required bit size, and use very
slow speed and a lot of pressure. As the hole begins to break through,
lighten up on the pressure and speed up the drill. Then switch to the
larger bit size and drill again, using plenty of cutting oil. I've
successfully used my Black & Decker 9.6-volt cordless drill for
drilling stainless, but it's a lot easier with my big Sears line-powered
variable speed drill, which has an orthogonal handle that makes it easier
to keep straight.
There's a bit of a controversy about the use of a center punch. Some say
that it 'work hardens' the material. I personally think it's about the
only way to keep the bit from walking away from the marked spot. There's
nothing more infuriating than drilling a hole, which is too far off center
to attach the thing you were planning to attach!
Be sure to trap and clean up any particles; while they won't rust, you
WILL be generating lots of sharp little shards of material that will wind
up painfully embedded in the soles of your feet if you aren't careful!
Norm Bernstein, 'Amoreena', C400 #105, msys@marisystems.com
Subj: Re: [C34] Stainless Steel Drilling?
Buy good quality cobalt drill bits from a machinist supply store. Worth
the extra $, No lubrication, medium speed
Gary Wiseman, gwiseman@ftn.net
Subj: Re: Stainless Steel Drilling?
Stainless grade steels are extremely soft due to the chrome and nickel
content. The more stain resistant, the softer the material. You need to
use extremely sharp tools to machine stainless, as the biggest problem is
build-up of material on the tool causing the tool to overheat and dull out
quickly. Lots of oil for cooling is also important. Tool speed and feed
speed can be determined with observation of the job. Higher tool speeds
are usually the best policy with a slower than normally used feed speed
that would be used to machine less stain resistant steels.
Regards from "GONE WITH THE WIND", C34, Naples, FL, Ron Euler,
sunshinesports@sprintmail.com
Subj: Re: Stainless Steel Drilling?
I have worked with stainless steel for many years and what I find
works for me is this: Prick punch the spot first or the drill may wander
before it bites into the steel. Then size a pilot bit using the web across
the desired bit's end, right at the peak. This way the boring bit starts
cutting using all of the cutting surface making it easier for the bit to
cut without wandering. Use a cutting lubricant if possible and keep your
speed low if you are cutting a large hole as stainless tends to heat up,
expand and bind. If you allow stainless to get too hot it will harden it
making it more difficult or next to impossible to drill, i.e. letting the
drill bit get red hot before stopping to sharpen or replace the bit.
Stainless steel is softer that carbon steel and will wear out drill bits
very quickly if proper procedures are not followed.
These same techniques work for aluminum as well.
Gary, C30 #1544, Wind Spirit, sailor@vermontel.net
Subj: Re: Stainless Steel Drilling?
I have drilled a lot of stainless steel over the years in my job as a
prototype builder. I have found that you should have a sharp drill, slow
drill speed and a lot of pressure on the drill bit. Use lubricant too, oil
is OK if you don't have any of the specialty lubes available. Good luck.
Gary Coppola, "GOTTAGO" C-30 #1100, Olcott Beach, NY, Gmcop@aol.com
Subj: Re: Stainless Steel Drilling?From: RBritton@telus.net
(Richard Britton)
I hope you saw my reply to a post a couple of days ago about drilling SS
to a larger daim. The full story is much longer than the following, as
there are precise conditions for every material, but I hope I can give you
a few ideas to help outside a machine shop. Remember to reduce heat as it
tends to destroy the "stainless-ness" of SS, type 304 more than
the true marine grade 316.
SS can be cut and drilled, but it is hard stuff and needs care. The
optimum is to have the work and the bit brought together in a drill press
or some other machine that gives you control. The key to drilling or
machining any metal is control of all factors. Always use a centre punch
at the start to prevent wandering of the bit. If your final size is more
than about 1/4", follow the punch with a pilot hole, which should be
the same diameter or a tiny bit larger than the web (the centre or area
that joins the two cutting flutes of the drill bit) again to ensure that
the drill does not wander or chatter. E.g. a 1/2" bit should have a
pilot hole of about 1/8". Avoid the use of progressive sizes in hard
materials as it is hell on the bit and the SS.
Because of the hardness of the SS, do not allow the drill bit's cutting
edge to "mildly" to scrape, rub or cut the SS or it will quickly
blunt the drill and further work harden the SS, making it almost
impossible to drill again. Drilling SS is a pretty brutal process; when
you get going, have immediate, continuous, strong, even, correct angle,
speed and steady pressure on the drill and pour on the cutting fluid,
which is as much of a coolant as anything. The bit is under great stress
and will otherwise heat up rapidly. You may need to stop and let it and
the SS cool or actually replace the bit before continuing. Use good
quality bits, as they are still cheap compared to the hassle of dealing
with an incomplete or poorly cut hole.
Unfortunately I do not have my data with me but the speed of drilling any
material varies inversely with the diameter of the hole. If I recall
correctly, a typical 1/16" bit should turn at something like 20,000
RPM, but that is optimum and few electric drills or presses can even
achieve that. Likewise a 1" bit is down below 100 RPM I think. I
believe that in SS a 1/8" diam should be about 2000 RPM but a
3/8" diam drops to about 500 RPM. Maybe an engineer on the list could
make this more accurate. However, on a hand-held electric drill, you just
have to use you best guestimate anyway. Check the full speed of your
electric drill and go from there. When holding the drill, brace yourself
firmly yet comfortably using elbows, a friend etc, so that you are rock
steady, can exert reasonably strong feed pressure – and will not be hurt
when the bit goes through or if it breaks.
I highly recommend a "high tech" cutting fluid called Rapid-Tap
that I used for years in industry. It is just amazing stuff and quite
inexpensive for the amount most of us would use. It seems to break down
the surface tension of the cutting operation which in turn prevents heat
build-up, allowing you to cut longer, and extends the life of your bits
many times over. It may damage paint so be careful of that. It is not
quite the same stuff as the traditional cutting fluids. It is like paint
thinners in consistency; makes a huge difference.
Richard Britton, Friendly Dragon, 1976 C30 New Westminster, B.C.
Aluminum Drilling ?
Original Question:
I am thinking of mounting a winch on the mast and this means I have to
drill new holes in the Aluminum Mast. How do I drill Aluminum? Drill Bit?
Drill Speed? Lubrication? Any experts out there?
Capt Al, #55 C34, "Kindred Spirit", http://kindred-spirit.net
Subj: Re: Aluminum Drilling ?
You asked about aluminum. You should have no problem with a wandering
or chattering bit - if you have a small pilot hole. The standard bits tend
to grab soft metal and jam - ever tried to drill lead?! If you need to
drill a lot of holes, and/or larger holes, the following very brief
description may help you. Softer metals like aluminum, copper etc do not
need a "chisel-like" sharp edge on the bit, but material should
be removed by more of a scraping action. To get this, sharpen the bit in
the usual way, but then (and it us against your instinct to do this!)
grind the cutting edge so that the inside surface of the flute has a tiny
face that is in line with the length of the bit, i.e. "straight
up" the drill. So this will leave you with the normal angle of the
drill under or at the end of the drill, but a scraping edge making contact
with the material from where the swarf (waste material) exits. Use regular
speeds, and I think you are unlikely to need cutting fluids, though I
believe in optimum conditions you would.Good luck and I hope this helps.
Richard Britton, Friendly Dragon, 1976 C30 New Westminster, B.C.
Subj: Re: Aluminum Drilling ?
Al : I have a main with reg. battens and a full batten main. I have no
problem raising either one with my "home made" lazyjacks. To
mount anything on the mast or boom drill and tap the hole so the item
(ridged vang, whisker pole track, winch etc.) can be secured properly with
a threaded stainless fastener. Start with a center punch. The hole should
be 2or3 drill sizes smaller than the bolt. The tap usually tells what size
hole to drill for. Use a little 3in1oil as it will keep the drill bit
sharp. Use medium speed and medium pressure. The aluminum alloy is soft
and easy to drill thru. Invest in a GOOD tap holder - it will make the job
much easier and have a nicely threaded hole. When mounting the item make
sure you put some anti seize or grease on the threads.
Ron, ronphylhill@erols.com
Subj: Re: Aluminum Drilling ?
Just about anything will drill aluminum. Don't go too large if you are
going to thread the holes. Get a good tap and it will specify the proper
size bit to use.
Richard, r_clack@hotmail.com
Subj: RE: Aluminum Drilling ?
For drilling in aluminum, ordinary bits are fine. Aluminum is soft as a
grape and easily drilled. If you're drilling holes that are going to be
tapped, drill a little bit undersized, and let the tap do the rest of the
work. I usually use a bit of cutting fluid, but I've also done without any
lubricant, and haven't had any problems. Be sure to trap and clean up any
particles; while they won't rust, you WILL be generating lots of sharp
little shards of material that will wind up painfully embedded in the
soles of your feet if you aren't careful!
Norm Bernstein, 'Amoreena', C400 #105, msys@marisystems.com
Subj: Re: [C34] Aluminum Drilling?
To drill Aluminum, use standard high-speed steel drills at medium speed.
If you're doing a lot of aluminum drilling you can relieve the web edges
slightly to reduce grabbing but for what we are doing just go with the
standard bits.
Gary Wiseman, Up Spirits #894, gwiseman@ftn.net
Subj: Re: [Aluminum Drilling ?]
I'll give you a tip. It'll cost you about 18 bucks though. For your
aluminum, always use some sort of punch, and go out and get a set of Black
and Decker Bullet bits. They are the easiest way to make round holes in
Aluminum, in my opinion. Otherwise it's easy to end up with triangles, and
especially if you are tapping holes, that's bad.
Have fun!, Tom, daurizio@usa.net
Important: The opinions expressed here are those of the individual contributors to this page, and not those of the Catalina 34 National Association or Catalina Yachts, Inc. Additionally, this material has not been reviewed by Catalina Yachts, Inc. for technical accuracy. This page's maintainer cannot guarantee the accuracy of this information or the desirability of suggested modifications or upgrades. Please obtain assistance from a competent marine mechanic or boatyard prior to making any significant modifications to your vessel.