I've got a job coming up to drill around 300 x 25mm diameter holes in some
powder coated steel electrical enclosures. The metal is 1mm thick, probably
30 - 35 thou. Punching is out, I need to do this using my drill press.

I've done a bunch of holes in the past using a step drill, and then spent
almost as much time again deburring the holes. I'de very much like to avoid
using coolant or Trefolex due to the cleanup involved with the enclosures.

I'd like to drill the holes in one go (ie not pilot then change & drill) any
recommendations as to the best approach or tool that I should use?

thanks

K Ludger wrote:
I've got a job coming up to drill around 300 x 25mm diameter holes in some
powder coated steel electrical enclosures. The metal is 1mm thick, probably
30 - 35 thou. Punching is out, I need to do this using my drill press.

I've done a bunch of holes in the past using a step drill, and then spent
almost as much time again deburring the holes. I'de very much like to avoid
using coolant or Trefolex due to the cleanup involved with the enclosures.

I'd like to drill the holes in one go (ie not pilot then change & drill) any
recommendations as to the best approach or tool that I should use?

thanks



Drill press be damned.

Punch!

In article ,
Richard wrote:

Drill press be damned.

Punch!

Seconded.
--
-Ed Falk,
http://thespamdiaries.blogspot.com/

"K Ludger" wrote in
:

I've got a job coming up to drill around 300 x 25mm diameter holes in
some powder coated steel electrical enclosures. The metal is 1mm
thick, probably 30 - 35 thou. Punching is out, I need to do this using
my drill press.

I've done a bunch of holes in the past using a step drill, and then
spent almost as much time again deburring the holes. I'de very much
like to avoid using coolant or Trefolex due to the cleanup involved
with the enclosures.

I'd like to drill the holes in one go (ie not pilot then change &
drill) any recommendations as to the best approach or tool that I
should use?

thanks



If you absolutely *insist* upon drilling, get yourself a bunch of 1" bi-
metallic hole saws and the appropriate mandrel.

The mandrel has a drill bit that will let you precisely spot the hole,
drill a pilot hole, and keep the saw centered.

Practice on some scrap 'till you get used to the amount of pressure you'll
need to apply.

On Sun, 21 Dec 2008 13:14:20 +0900, "K Ludger"
wrote:

I've got a job coming up to drill around 300 x 25mm diameter holes in some
powder coated steel electrical enclosures. The metal is 1mm thick, probably
30 - 35 thou. Punching is out, I need to do this using my drill press.

I've done a bunch of holes in the past using a step drill, and then spent
almost as much time again deburring the holes. I'de very much like to avoid
using coolant or Trefolex due to the cleanup involved with the enclosures.

I'd like to drill the holes in one go (ie not pilot then change & drill) any
recommendations as to the best approach or tool that I should use?

thanks

===========
If drill you must, you might look at a hole saw.

I don't see a 25 m/m listed, but this will give you an idea.
http://www.use-enco.com/CGI/INSRIT?P...PARTPG=INLMK32
you will also need the driver
http://www.use-enco.com/CGI/INPDFF?PMPAGE=606&PMCTLG=00

As the metal is pretty thin you might want to consider an
adjustable hole cutter. These are dangerous.
http://www.use-enco.com/CGI/INSRIT?P...&PARTPG=INLMK3

An other option if your drill chuck is big enough [3/4 inch] is
to use a rotobroch. Good but spendy
http://www.use-enco.com/CGI/INSRIT?P...PARTPG=INLMK32

http://www.rotabroach.co.uk/en/produ...s/default.aspx
shows an exact 25m/m their sku SRC250. They also show a morse
taper adapter to replace the chuck.

Most any good mill supply house should be able to order for you
if they don't have in stock. Enco items are exmples.

Let us know what you decide on and how it works


Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).

"K Ludger" wrote:

I'd like to drill the holes in one go (ie not pilot then change & drill) any
recommendations as to the best approach or tool that I should use?

Well, looks like you need to use a hole saw. Wonder if they make them with brazed in
carbide teeth?

I'd drill for a green lee punch and punch. I'd also beg borrow or steal a hydraulic
model or have an air ratchet to drive a non-hydraulic punch.



Wes

The ball thrust bearings make those bolted punches very easy to operate.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Wes" wrote in message
...
"K Ludger" wrote:

I'd like to drill the holes in one go (ie not pilot then change & drill)
any
recommendations as to the best approach or tool that I should use?

Well, looks like you need to use a hole saw. Wonder if they make them
with brazed in
carbide teeth?

I'd drill for a green lee punch and punch. I'd also beg borrow or steal
a hydraulic
model or have an air ratchet to drive a non-hydraulic punch.



Wes

On Sun, 21 Dec 2008 00:16:08 -0500, the infamous "Wild_Bill"
scrawled the following:

The ball thrust bearings make those bolted punches very easy to operate.

Unless you buy a truly cheaparse copy from HF, complete with
mismatched threads http://tinyurl.com/7cvcdl . This is one of the few
tools they got -entirely- wrong.

RUN AWAY! RUN AWAY!


--
It is pretty hard to tell what does bring happiness;
poverty and wealth have both failed.
-- Kin Hubbard

"Wild_Bill" wrote:

The ball thrust bearings make those bolted punches very easy to operate.

Yup, and the slugbuster profile on the newer ones seem to cut through easier too.

Wes

On Sun, 21 Dec 2008 13:14:20 +0900, "K Ludger"
wrote:

I've got a job coming up to drill around 300 x 25mm diameter holes in some
powder coated steel electrical enclosures. The metal is 1mm thick, probably
30 - 35 thou. Punching is out, I need to do this using my drill press.

Rotabroach. Rotabroach is a brand name, annular cutter is the generic
description. Not cheap, but will make clean, accurate holes in thin
material without damaging the finish. Make sure your drill press will
turn slowly enough, around 300RPM for mild steel. You may need an
adapter, as they usually have a 3/4" shank for mounting in a mag
drill. I use them on control panels for installing oiltight switches
when I want something more accurate than a Greenlee punch.
http://www.imatech.com.au/images/products/28.jpg

--
Ned Simmons

You don't say what size or HP your drill press is. As you probably already
know, the correct time to make the holes would be before the finish coating
is applied.

How will you be locating the location of the center of the hole? Center
punch? That's about how long a punch would take to make the hole.
Any drilling or hole saw method will take considerably longer than punching.
Some odd/uncommon/custom carbide-tipped spade bit with a center pilot drill
may be faster if you could find, or make such a cutter.

You will most likely spend a considerable amount of time deburring the
holes, regardless of the method you use to make the holes.
Step drills will deburr the entry side of the hole if you just kiss the next
step on the hole.
If the hole is located in the back of a box (not the sides), the deburring
time could be quite a bit faster, by flipping the part over to deburr.

I would hate to attempt to make that number of the holes without any cutting
lubricant, maybe not liquid, but at least beeswax or even bar soap (not
highly effective, but not extremely messy).

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"K Ludger" wrote in message
...
I've got a job coming up to drill around 300 x 25mm diameter holes in some
powder coated steel electrical enclosures. The metal is 1mm thick,
probably 30 - 35 thou. Punching is out, I need to do this using my drill
press.

I've done a bunch of holes in the past using a step drill, and then spent
almost as much time again deburring the holes. I'de very much like to
avoid using coolant or Trefolex due to the cleanup involved with the
enclosures.

I'd like to drill the holes in one go (ie not pilot then change & drill)
any recommendations as to the best approach or tool that I should use?

thanks

On 2008-12-21, Wild_Bill wrote:
You don't say what size or HP your drill press is. As you probably already
know, the correct time to make the holes would be before the finish coating
is applied.

And -- before the metal is bent to make the box.

How will you be locating the location of the center of the hole? Center
punch? That's about how long a punch would take to make the hole.

Assuming a proper punch (e.g. a turret punch), though it is nice
to have a center punch mark to feel for with the pip on the center of
the punch.

Any drilling or hole saw method will take considerably longer than punching.

Agreed -- unless it is a case of:

1) Drill a pilot hole.

2) Assemble a Greenlee chassis punch.

3) Spend quite a bit of time cranking on the drive screw.

(this can be made easier by using a hydraulic drive for the
punch, but not as nice as a lever operated turret punch, or
even a floor standing single station punch of similar size.)

Some odd/uncommon/custom carbide-tipped spade bit with a center pilot drill
may be faster if you could find, or make such a cutter.

And firmly clamp down the sheet metal to keep it from spinning
and slicing open your wrists.

You will most likely spend a considerable amount of time deburring the
holes, regardless of the method you use to make the holes.

Yep -- except for perhaps a CNC water jet.

Step drills will deburr the entry side of the hole if you just kiss the next
step on the hole.

Except that I think that the largest step drill size is 1",
which is his target dimension -- so there *is* no next step to use for
the deburr operation.

If the hole is located in the back of a box (not the sides), the deburring
time could be quite a bit faster, by flipping the part over to deburr.

Or if it is done before the box is folded.

I would hate to attempt to make that number of the holes without any cutting
lubricant, maybe not liquid, but at least beeswax or even bar soap (not
highly effective, but not extremely messy).

Agreed. The only lubricant free method which I see as practical
is the above-mentioned CNC water jet -- which could probably cut several
stacked up at once.

Didn't he say that he was going to be cutting in Stainless?
That will make it more difficult for all methods except the waterjet.

Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On Sun, 21 Dec 2008 13:14:20 +0900, "K Ludger"
wrote:

I've got a job coming up to drill around 300 x 25mm diameter holes in some
powder coated steel electrical enclosures. The metal is 1mm thick, probably
30 - 35 thou. Punching is out, I need to do this using my drill press.

I've done a bunch of holes in the past using a step drill, and then spent
almost as much time again deburring the holes. I'de very much like to avoid
using coolant or Trefolex due to the cleanup involved with the enclosures.

I'd like to drill the holes in one go (ie not pilot then change & drill) any
recommendations as to the best approach or tool that I should use?

thanks

If the enclosures are built, I don't have any advice, although
personally I'd punch them. If they are not built, design your
enclosures carefully, locating all holes, square round, large small,
doesn't matter. Send the drawing (I use email) to an enclosure
fabricator near you, and they'll plasma cut the holes in the flat
sheet, bend up, weld, and powder coat the boxes. Saves a lot of money
and hassle, plus hole edges are powder coated. That's about the only
way I'll do enclosures of any complexity any more. I've also done it
in 4X.

Pete Keillor

In article , "K Ludger" wrote:
I've got a job coming up to drill around 300 x 25mm diameter holes in some
powder coated steel electrical enclosures. The metal is 1mm thick, probably
30 - 35 thou. Punching is out, I need to do this using my drill press.

I've done a bunch of holes in the past using a step drill, and then spent
almost as much time again deburring the holes. I'de very much like to avoid
using coolant or Trefolex due to the cleanup involved with the enclosures.

I'd like to drill the holes in one go (ie not pilot then change & drill) any
recommendations as to the best approach or tool that I should use?

The ideal thing for sheet metal is something that can remove a disk,
rather than having to chew out all or the material. I've never used a
RotaBroach, but if you can afford one, that may be your best bet. I'm
not sure how bad they are for burrs. If you don't like deburring, a hole
saw will probably be worse than a step drill. A trepanning tool might
also work if you can hold & support it well.

Actually, I'm surprised you have a problem with burrs with the step
drill. A good quality one (not a Chinese knock-off) has always cut a
pretty clean hole for me, and if you move up towards the next step, you
can deburr the top side in the same operation. For the backside, I use
soemthing like a Noga or a Royal with the "?" shaped blade to get the far
side of the hole.

With any approach, having a good hard backing surface will help with
burrs and safety. If the metal can flex, it can grab, expecially if you
you a single point adjustable cutter. A trepanning tool tends to scrape
more than dig in, so it's a bit safer.

Doug White

Annular cutter.

Jancy and Hougen are a couple of brands.

You will quickly get a feel for the pressure required,
and leave very little burr.

K Ludger wrote:

I've got a job coming up to drill around 300 x 25mm diameter holes in some
powder coated steel electrical enclosures. The metal is 1mm thick, probably
30 - 35 thou. Punching is out, I need to do this using my drill press.

I've done a bunch of holes in the past using a step drill, and then spent
almost as much time again deburring the holes. I'de very much like to avoid
using coolant or Trefolex due to the cleanup involved with the enclosures.

I'd like to drill the holes in one go (ie not pilot then change & drill) any
recommendations as to the best approach or tool that I should use?

thanks



I would drill each hole location with a drill the same size as the pilot
drill of a good carbide tipped hole saw. I would remove the pilot
drill of the hole saw and in stead use a solid mandrel. A hole punch is
a pain for more than a couple of holes. A cheap hole saw will make a
mess after it starts to get a little dull.

John

What's that Lassie? You say that K Ludger fell down the old
rec.crafts.metalworking mine and will die if we don't mount a rescue
by Sun, 21 Dec 2008 13:14:20 +0900:

I've got a job coming up to drill around 300 x 25mm diameter holes in some
powder coated steel electrical enclosures. The metal is 1mm thick, probably
30 - 35 thou. Punching is out, I need to do this using my drill press.

I've done a bunch of holes in the past using a step drill, and then spent
almost as much time again deburring the holes. I'de very much like to avoid
using coolant or Trefolex due to the cleanup involved with the enclosures.

I'd like to drill the holes in one go (ie not pilot then change & drill) any
recommendations as to the best approach or tool that I should use?

thanks

Can you use a plasma cutter. Make a template to locate and size your
hole. Very quick. You might need to protect the inside surfaces with
a piece of scrap or something.

Dan
--

Dan H.

There are some carbide hole cutters and carbide tipped hole saws at McMaster
Carr page 2343.
http://www.mcmaster.com/

Copied from their catalog:
Carbide Hole Cutters

Great for cutting smooth, clean holes, these heavy duty hole cutters cut
sheet metal, stainless steel, and plastics up to 1/4" thick. Carbide teeth
are brazed into the cutter to leave smooth holes. Cutters have a
spring-ejector system for easy slug removal. Shank is 1/2" dia. Pilot drill
is 1/4" dia.

RogerN

"K Ludger" wrote in message
...
I've got a job coming up to drill around 300 x 25mm diameter holes in some
powder coated steel electrical enclosures. The metal is 1mm thick,
probably 30 - 35 thou. Punching is out, I need to do this using my drill
press.

I've done a bunch of holes in the past using a step drill, and then spent
almost as much time again deburring the holes. I'de very much like to
avoid using coolant or Trefolex due to the cleanup involved with the
enclosures.

I'd like to drill the holes in one go (ie not pilot then change & drill)
any recommendations as to the best approach or tool that I should use?

thanks