I need to put a 3/4" diameter hole in the front of my kitchen range hood.
Never mind why -- that's kind of involved. It's stainless steel, about 20ga,
and it would be a real PITA to dismount it and take it anywhere. I really need
to make the hole with the unit in place.

What's the best tool to use for that job?

Picture he
http://www.maytag.com/catalog/produc...at=7&prod=1478

What's the best tool to use for that job?


Doug

A 3/4" knockout punch.

Bob AZ

On 2010-05-26, Doug Miller wrote:
I need to put a 3/4" diameter hole in the front of my kitchen range hood.
Never mind why -- that's kind of involved. It's stainless steel, about 20ga,
and it would be a real PITA to dismount it and take it anywhere. I really need
to make the hole with the unit in place.

What's the best tool to use for that job?

Picture he
http://www.maytag.com/catalog/produc...at=7&prod=1478

Step drill?

"Doug Miller" wrote in message
...
I need to put a 3/4" diameter hole in the front of my kitchen range hood.
Never mind why -- that's kind of involved. It's stainless steel, about
20ga,
and it would be a real PITA to dismount it and take it anywhere. I really
need
to make the hole with the unit in place.

What's the best tool to use for that job?

Picture he
http://www.maytag.com/catalog/produc...at=7&prod=1478

3/4 stick of dynamite should do it.

On 5/25/2010 6:57 PM, Doug Miller wrote:
I need to put a 3/4" diameter hole in the front of my kitchen range hood.
Never mind why -- that's kind of involved. It's stainless steel, about 20ga,
and it would be a real PITA to dismount it and take it anywhere. I really need
to make the hole with the unit in place.

What's the best tool to use for that job?

Picture he
http://www.maytag.com/catalog/produc...at=7&prod=1478

A 11132-3 Rotabroach on a P/N 11123 arbor at 250 RPM

--Winston

On 2010-05-26, Doug Miller wrote:
I need to put a 3/4" diameter hole in the front of my kitchen range hood.
Never mind why -- that's kind of involved. It's stainless steel, about 20ga,
and it would be a real PITA to dismount it and take it anywhere. I really need
to make the hole with the unit in place.

What's the best tool to use for that job?

Picture he
http://www.maytag.com/catalog/produc...at=7&prod=1478

I would sort of toss up between a step drill (unibit) which
would make it to 3/4" or a Greenlee Chassis punch. If the latter, best
to get a ball bearing drive screw, and put plenty of good grease on the
screw threads. Since it is stainless it will fight you with either
approach. If you use the chassis punch, and are not going to put
something *in* the hole, put the cup shaped die on the inside and the
punch on the outside, so the burrs will be pointed in. With the Unibit,
you probably won't have much in the way of burrs -- especially if it has
a step beyond the 3/4" so you could use the start of that to cut off any
burrs.

If you were making a *lot* of the holes, I would suggest a
hydraulic drive on the chassis punch.

Be careful not to use a Greenlee knockout punch, because the
diameters don't match the names there -- they match the conduits for
which the knockouts are used.

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 2010-05-26, Bob AZ wrote:

What's the best tool to use for that job?


Doug

A 3/4" knockout punch.

Not if he needs a 3/4" hole. If you had said a chassis punch, I
would agree -- but knockout punches make oversized hole to mate with
conduit fittings and such.

Bob AZ

Enjoy,
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 May 26, 1:17*am, "DoN. Nichols" wrote:
On 2010-05-26, Bob AZ wrote:
* * * * Not if he needs a 3/4" hole. *If you had said a chassis punch, I
would agree -- but knockout punches make oversized hole to mate with
conduit fittings and such.

This one is stamped "1/2 conduit 7/8 dia".

jsw

A 11132-3 Rotabroach on a P/N 11123 arbor at 250 RPM

I think I agree. Hougen all the way... But maybe slower RPM if you can
figure out a way to do so... That hand drill is probably going to be too
fast. Cycle on and off quite often to let the tool tip cool off, etc. You
want as little heat as possible there.

Push HARD on the tool until breakthrough or that stainless will kill the
tool. Maybe put some cooking oil on it to cool it off if you don't want
real cutting oil anywhere near it.
--


Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com
Production Tapping: http://Production-Tapping-Equipment.com/
Flagship Site: http://www.Drill-N-Tap.com
VIDEOS: http://www.youtube.com/user/AutoDrill

V8013-R

On 5/26/2010 5:13 AM, Joe AutoDrill wrote:
A 11132-3 Rotabroach on a P/N 11123 arbor at 250 RPM

I think I agree. Hougen all the way... But maybe slower RPM if you can
figure out a way to do so... That hand drill is probably going to be too
fast. Cycle on and off quite often to let the tool tip cool off, etc. You
want as little heat as possible there.

Push HARD on the tool until breakthrough or that stainless will kill the
tool. Maybe put some cooking oil on it to cool it off if you don't want
real cutting oil anywhere near it.

Yes, stay under the skin and avoid work hardening.
A moment's inattention and you will have a journal bearing
instead of a hole.

Consider clamping a chunk of 2x4 behind the sheet so
you can maintain high pressure as you break through.

--Winston

DoN. Nichols wrote:
Be careful not to use a Greenlee knockout punch, because the
diameters don't match the names there -- they match the conduits for
which the knockouts are used.

Good Luck,
DoN.
Use a " Chassis " punch they are as marked.
...lew...

On Wed, 26 May 2010 09:03:20 -0600, Lewis Hartswick
wrote:

DoN. Nichols wrote:
Be careful not to use a Greenlee knockout punch, because the
diameters don't match the names there -- they match the conduits for
which the knockouts are used.

Good Luck,
DoN.
Use a " Chassis " punch they are as marked.
...lew...

Yup. They don't tend to be rated for SS but I doubt one hole is going
to wreck them. Should cost about $40 new.

http://www.toolup.com/greenlee/730bb-3/4.html

(you have to drill a pilot hole for the bolt first)


Or a step drill:

http://www.mcmaster.com/#8841a23/=79atvx

On May 25, 7:57*pm, (Doug Miller) wrote:
I need to put a 3/4" diameter hole in the front of my kitchen range hood.
Never mind why -- that's kind of involved. It's stainless steel, about 20ga,
and it would be a real PITA to dismount it and take it anywhere. I really need
to make the hole with the unit in place.

What's the best tool to use for that job?

Picture hehttp://www.maytag.com/catalog/produc...at=7&prod=1478

If you have access to the back side, a chassis punch is the tool,
otherwise you'll have to use something like a step drill. If you can
back the metal up with a block of wood, a hole saw might do it. Or a
nibbler, if you don't mind doing some filing for cleanup. I'd put
tape down over a wide area before trying anything, though. Saves
having oopsies that will haunt you as long as the thing is installed.
If you drill, use a slow-speed drill. Just thought of another
alternative, 1/4" air die grinder with a carbide rasp bit, used one on
an electrical box where I didn't have punch or much of anything else.
Would take a steady hand. Was fast. Mark out the diameter on the
tape, punch a 1/4" hole in the center and have at it.

Stan

Lewis Hartswick wrote:
DoN. Nichols wrote:

Be careful not to use a Greenlee knockout punch, because the
diameters don't match the names there -- they match the conduits for
which the knockouts are used.

Good Luck,
DoN.

Use a " Chassis " punch they are as marked.
...lew...
Undeed, and Greenlee and others make BOTH types.

Electrical "Knockout" punches are like Helicoil taps ... NOT the size
they are marked and you may be expecting. All are very handy, but use
with caution!

Dan Mitchell
============

Bob AZ wrote:


What's the best tool to use for that job?


Doug

A 3/4" knockout punch.


Don't think so. I had to look this up today to order a grommet. A 1/2" conduit knock out
punch is 7/8".

Now if Doug really wants 3/4", 34685A69
Round Knockout Hole Punch for 3/4" Hole Diameter
In stock at $41.29 Each

Can you use a unibit?


Wes

(Doug Miller) wrote:

I need to put a 3/4" diameter hole in the front of my kitchen range hood.
Never mind why -- that's kind of involved. It's stainless steel, about 20ga,
and it would be a real PITA to dismount it and take it anywhere. I really need
to make the hole with the unit in place.

What's the best tool to use for that job?


Not my favorite tool but do you have a dremel tool? If so, draw a circle, start grinding.

Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller

On 2010-05-26, Edward A. Falk wrote:
In article ,
DoN. Nichols wrote:
I would sort of toss up between a step drill (unibit) which
would make it to 3/4" or a Greenlee Chassis punch.

For 20ga? Definately the Chassis punch.

If mild steel, or aluminum (of the stated (20 ga IIRC)
thickness), yes.

For SS I think that maybe the step drill would work a bit
better -- but I'm not sure.

If we were dealing with 16 ga or thicker, and staying with SS, I
would feel stronger about the preference for the step drill.

Enjoy,
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 2010-05-26, Jim Wilkins wrote:
On May 26, 1:17*am, "DoN. Nichols" wrote:
On 2010-05-26, Bob AZ wrote:
* * * * Not if he needs a 3/4" hole. *If you had said a chassis punch, I
would agree -- but knockout punches make oversized hole to mate with
conduit fittings and such.

This one is stamped "1/2 conduit 7/8 dia".

So -- they've started marking with the actual diameter as well?
Not back when I was buying them new. :-)

So -- what size knockout punch would be needed to make a 3/4"
diameter hole? Something smaller than 1/2" conduit -- and I don't think
that they *make* anything smaller. :-)

Enjoy,
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 ---

A lot of suggestions, but cmon - to a Real Metalworker there's only one
way - plasma cutter. Just ask Ernie G.

Bob

In article , wrote:

Now if Doug really wants 3/4", 34685A69
Round Knockout Hole Punch for 3/4" Hole Diameter
In stock at $41.29 Each

Yikes!

Can you use a unibit?

Dunno. Don't own one, never tried. Guess I can learn. :-)

In article , wrote:
(Doug Miller) wrote:

I need to put a 3/4" diameter hole in the front of my kitchen range hood.
Never mind why -- that's kind of involved. It's stainless steel, about 20ga,
and it would be a real PITA to dismount it and take it anywhere. I really need
to make the hole with the unit in place.

What's the best tool to use for that job?


Not my favorite tool but do you have a dremel tool? If so, draw a circle,
start grinding.

Yes, I do have a Dremel tool. Don't like the idea of turning that much metal
into powder, though, especially in my kitchen.

Spehro mentioned step drills - that is the way to go.

I have a tool box full of Greenlee Chassis punches. 3/4" means not much
for the bolt.

Step drills are low cost - made for sheet metal. I have a set of them
and pick one of three to be in the range I need.

Martin

Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
"Our Republic and the Press will Rise or Fall Together": Joseph Pulitzer
TSRA: Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Charter Charter Founder
IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com/

On 5/25/2010 8:57 PM, Doug Miller wrote:
I need to put a 3/4" diameter hole in the front of my kitchen range hood.
Never mind why -- that's kind of involved. It's stainless steel, about 20ga,
and it would be a real PITA to dismount it and take it anywhere. I really need
to make the hole with the unit in place.

What's the best tool to use for that job?

Picture he
http://www.maytag.com/catalog/produc...at=7&prod=1478

Chassis punches are as marked. The knockout ones are for conduit pipe and
are the inside as to the tubing spec.

Martin


Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
"Our Republic and the Press will Rise or Fall Together": Joseph Pulitzer
TSRA: Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Charter Charter Founder
IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com/

On 5/26/2010 12:50 PM, danmitch wrote:
Lewis Hartswick wrote:
DoN. Nichols wrote:

Be careful not to use a Greenlee knockout punch, because the
diameters don't match the names there -- they match the conduits for
which the knockouts are used.

Good Luck,
DoN.

Use a " Chassis " punch they are as marked.
...lew...
Undeed, and Greenlee and others make BOTH types.

Electrical "Knockout" punches are like Helicoil taps ... NOT the size
they are marked and you may be expecting. All are very handy, but use
with caution!

Dan Mitchell
============

On 2010-05-27, Doug Miller wrote:
In article , wrote:
(Doug Miller) wrote:

I need to put a 3/4" diameter hole in the front of my kitchen range hood.
Never mind why -- that's kind of involved. It's stainless steel, about 20ga,
and it would be a real PITA to dismount it and take it anywhere. I really need
to make the hole with the unit in place.

What's the best tool to use for that job?


Not my favorite tool but do you have a dremel tool? If so, draw a circle,
start grinding.

Yes, I do have a Dremel tool. Don't like the idea of turning that much metal
into powder, though, especially in my kitchen.

Don't worry -- it won't be powder -- it will be a lifetime
supply of little stainless steel needles which will embed in you (and
whoever else works in there) for the next few years as you clean out
from under various things near the work area. And -- unlike mild steel,
it won't dull with rust over the years. :-)

And -- since it is stainless -- you can't even use a magnet to
capture it as it is created.

Unibit (step drill) leaves fewer and larger chips. Easier to
clean up.

Chassis punch (*not* knockout punch for this) leaves only one
stainless steel (potato) chip (aside from those produced when you drill
for the pilot hole.

1/2" chassis punches use something like 1/4 or 5/16" draw screws
IIRC. Larger goes to 3/8", 1/2" and larger -- at least 1", though I'm
not sure where the breakover to the next size happens -- whether it is
before or after the 3/4" size. (I could go downstairs and see -- *if* I
happen to have a 3/4" one in my collection.) In any case, measure the
drawscrew size and go larger for the pilot hole, because the punched out
piece of metal takes on the shape of a Pringles pseudo potato chip which
causes the hole to tighten on the screw. And even if you have a newer
one with the "slugbuster" feature (chisel edges in the punch to cut the
punched out slug into two halves for easier removal from the die body) I
have doubts about this feature working in the SS you are making the hole
in. In any case, you would need a vise to hold the punch from turning
(after you had punched out the actual hole) to tighten it enough for the
slugbuster to work.

If you use the chassis punch, put masking tape (or perhaps duct
tape) over the area around the hole, and draw a big '+' though the
center of the hole before drilling the pilot. The chassis punch has
four straight lines scribed on the OD to line up with the plus to set the
location properly. The tape will also keep the pilot drill bit from
walking as you try to drill the pilot hole.

The hole size sounds like it may be for a pilot light to remind
you the fan in the hood is on, or perhaps an industrial switch to
control the fan.

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 ---

In article , "DoN. Nichols" wrote:
[...]
Unibit (step drill) leaves fewer and larger chips. Easier to
clean up.

I think that's the way I'm going to go. Thanks to all who suggested this.
[...]
The hole size sounds like it may be for a pilot light to remind
you the fan in the hood is on, or perhaps an industrial switch to
control the fan.

No, it's for a rocker switch to control a solenoid gas valve for our gas
cooktop. My inlaws live with us; MIL has some form of senile dementia, and
can't possibly be trusted with a gas stove. So we've been shutting off the gas
to the kitchen whenever we leave the house, but that's a PITA because the
shutoff is in the basement. I plan on putting a 24V transformer and solenoid
gas valve in the cabinet under the cooktop, and the switch in the range hood.
Even if she sees the switch and figures out what it's for (vanishingly
unlikely), she can't reach it anyway: due to shoulder problems, she can't
reach anything above her own eye level. Planned location for the switch is
above *mine*, and I'm 6" taller than she is.

What's that Lassie? You say that Doug Miller fell down the old
rec.crafts.metalworking mine and will die if we don't mount a rescue
by Wed, 26 May 2010 01:57:30 GMT:

I need to put a 3/4" diameter hole in the front of my kitchen range hood.
Never mind why -- that's kind of involved. It's stainless steel, about 20ga,
and it would be a real PITA to dismount it and take it anywhere. I really need
to make the hole with the unit in place.

What's the best tool to use for that job?

Plasma cutter. If you have access to one. Make a template in
plywood, test on scrap.
--

Dan H.
northshore MA.

In article , "Because We Carry the Fire?" wrote:


"Doug Miller" wrote in message
...
I need to put a 3/4" diameter hole in the front of my kitchen range hood.
Never mind why -- that's kind of involved. It's stainless steel, about
20ga,
and it would be a real PITA to dismount it and take it anywhere. I really
need
to make the hole with the unit in place.

What's the best tool to use for that job?

Picture he
http://www.maytag.com/catalog/produc...at=7&prod=1478

3/4 stick of dynamite should do it.

plonk

"Doug Miller" wrote in message
...
In article , "Because We Carry
the Fire?" wrote:


"Doug Miller" wrote in message
...
I need to put a 3/4" diameter hole in the front of my kitchen range
hood.
Never mind why -- that's kind of involved. It's stainless steel, about
20ga,
and it would be a real PITA to dismount it and take it anywhere. I
really
need
to make the hole with the unit in place.

What's the best tool to use for that job?

Picture he
http://www.maytag.com/catalog/produc...at=7&prod=1478

3/4 stick of dynamite should do it.

plonk

More like *boom*

Doug Miller wrote:

In article , "DoN. Nichols" wrote:
[...]
Unibit (step drill) leaves fewer and larger chips. Easier to
clean up.

I think that's the way I'm going to go. Thanks to all who suggested this.
[...]
The hole size sounds like it may be for a pilot light to remind
you the fan in the hood is on, or perhaps an industrial switch to
control the fan.

No, it's for a rocker switch to control a solenoid gas valve for our gas
cooktop. My inlaws live with us; MIL has some form of senile dementia, and
can't possibly be trusted with a gas stove. So we've been shutting off the gas
to the kitchen whenever we leave the house, but that's a PITA because the
shutoff is in the basement. I plan on putting a 24V transformer and solenoid
gas valve in the cabinet under the cooktop, and the switch in the range hood.
Even if she sees the switch and figures out what it's for (vanishingly
unlikely), she can't reach it anyway: due to shoulder problems, she can't
reach anything above her own eye level. Planned location for the switch is
above *mine*, and I'm 6" taller than she is.


Is there a cabinet over the hood? Just make a small metal box and
hide it inside the cabinet.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.