Should a drill press used for drilling holes through 1/4 inch stainless
steel have any different characteristics than a drill press used for wood
work? Our applications are fairly trivial: maybe once a month we would
need to drill new screw placement holes in thick stainless retaining plates.
So we need a small drill press, but I want to make sure we don't overlook
any specific characteristics that a drill press intended for metal use
depends what diameter drill your spinning, but metal drilling needs to go
slower than wood.
bigger drills, more slower, once you go past 1/2" dia. drilling in metal,
you really need to slow down. Drill presses made for woodworking are
generally unsuitable for holes in metal larger than 1/4" dia, unless you
like sharpening & replacing drill bits alot.
Drilling "thick" stainless, you have no chance in hell with a drill press
that runs at woodworking speeds. You'll burn every bit even at the low speed
end. Also, you have little chance with 1/4" bits in "thick" stainless unless
you have a pretty rigid drill press that can run at very moderate
metalworking speeds. Somebody here will know the specific RPM, but it's 'way
A drill press that will cover the appropriate speeds for both is a not very
common. My floor model 50-year-old Walker-Turner, which is belt-driven, will
just do it, but it's because I have the intermediate pulley ("third wheel")
option for it. It's just barely rigid enough for drilling stainless with a
1/4" bit, partly because I had a lot of experience drilling many hundreds --
probably thousands -- of stainless pieces when I worked in a shop. It
requires some practice to keep adequate pressure on the bit without
springing the whole affair or slipping the belt, unless the drill press is a
heavy industrial model. If you don't keep adequate pressure (feed pressure,
that is) on it, you'll work-harden the stainless, burn the bit, and make it
extremely difficult to get the hole re-started.
The best bet in a commercial setting is to have one drill press appropriate
for each task. In fact, I prefer drilling thick stainless in a Bridgeport or
For a half inch drill bit in stainless you want a drill press that will go
as slow as 300 rpm. Most better quality woodworking drill presses can go
A gearbox driven drill press gets very expensive but for half inch and
less you could get by with a vee belt driven drill press.
1/3 horsepower motor would be on the weak side.. look for an honest half
I meant to ask, how does it do in stainless with a 0.5" bit? That's really
pushing it in thick stock, with a woodworking drill press. My Walker-Turner
won't do it, even though it has the right rpm. I have squeaked through with
3/8" bits, after drilling an 1/8" pilot hole. But that's not the way to go
for commercial work.
It is really handy to have T-slots milled into the table so that you
can mount a vise or jigs to it. Wood doesn't tend to spin as much as
metal when drilling, and it causes less damage when it does, so that
feature is often overlooked on the woodworking DPs, where the work is
easily held by hand.
Dig up the recommended cutting speed in surface feet per minute, for
the materials you are cutting, and the drill materials you are using,
and start from there.
Too fast cooks drills, too slow cost you time.
Some materials are just nicer to work with, too, and are less picky
about speeds and feeds. 304 is not one of those, for example.
This info is available in the American Machinist's Handbook. My copy
is over 40 years old.
Machinerys Handbook may have it, also.
Or try a text book from a technical college on machine tool operation.
IIRC this topic was discussed in this forum not too long ago (last
year?) try searching for it.
If you get stuck re-state your question here and we will see what we
For cutting 1/4 inch stainless (let's say 300 series) which of the bit types
should we be preferring:
- high speed steel
- uncoated carbide
- coated carbide
If it matters, then let's assume that the application is drilling 1/4 inch
diameter holes in the 300 series stainless plates that are about 1/4 inch
I'd buy a quality machine - one that can change spindle speed from metal
rates - slow to those of faster wood rates. Some wood is slow. But when
using it as a shaper and and such - it is fast.
The 1/4" Stainless is not a trivial task. Make sure you have ample clamping
ability to hold the work tight. A catch can whip a sheet or bar and
really spoil a day of someone.
A nice large flat table and an adjustable speed - belts are ok - you say
once a month change the belts for a job. Cheaper than electronics, but
not as handy.
Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
TSRA, Life; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member.
High Speed Steel.
Working stainless is not the "nearly impossible" task that some people
seem to think it is. I've been machining stainless since the 1950's
using high speed steel tooling with no problems.
There are two areas you need to address in machining stainless -
cutting speed, and feed rate. As a general statement you want the
proper cutting speed (RPM), or a little slower, and the highest feed
that the tool will handle.
For a 1/4"HSS drill, look up the cutting speed for HSS and the
stainless alloy you are using.
300 series 50 - 70 FPM. Using the lower speed the drill RPM will be:
50 X ((12/(Pi X D))
50 X (12/(3.1416 X 0.25)) = 763 RPM - set the drill press for that
speed or slower
Now use as high a pressure on the drill press handles that the drill
bit will stand. The chips will come off the work as spirals and may be
a light brown; if they are dark brown or blue slow the RPM.
As the drill starts to break through the bottom you should be able to
feel it and lighten up on the pressure just a bit. If you can't feel
the drop in pressure just use a piece of wood as a backing block until
you get the feel.
When people refer to stainless as being hard it is rather that
stainless work hardens very rapidly. Letting your drill spin without
cutting for just a second results in a work hardened surface that the
drill can no longer cut.
The thing you want to remember above all else is "keep the speed low
and the feed high" and you'll find that drilling stainless is no more
difficult then drilling mild steel.
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On Tue, 30 Oct 2007 22:40:12 -0400,
"T>depends what diameter drill your spinning, but metal drilling needs to go
I have a cheapo YingTong drill press, 2MT, 16mm chuck, 16 speeds.
I only run it at 200 ? rpm ( lowest speed), no matter what size drill
bit, 3mm to 25mm in steel or wood, 6mm to 70mm in Forstner bits (wood)
or up to 150mm holesaw in steel or wood. I am just too lazy to
change the belt on the pulleys. Works for me.
Most important is to check runout on the chuck, mine is negligible.