I've worked with wood most of my life, but I'm not as experienced with
metals... I recently found that I have to do a project for work that
involves drilling multiple holes through both sides of 3/4"x 3/4" and
1/16 thick square aluminum tube to make antennas. Imagine a TV antenna
basically... There needs to be multiple matched holes along each tube,
and into those holes, 1/4" solid round will be inserted through both
sides. In other words, the holes on both sides of the tubing have to be
aligned pretty darn well, otherwise a slight misalignment will
translate to the 1/4" round being way off center by the time it gets to
the end... Which is about 1-2 feet long. There will be a tad bit of
wiggle room since the round will be attached by threads on the end, and
a nuts on both sides of the square tube, but not a whole lot.

I had no idea this would be so difficult. I went and got a Sears 9"
bench drill press and proceeded by clamping the tube into a press vise.
I figured once I had it lined up and centered, I could just slide the
tube down for each hole... Wrong. There seems to be no rhyme or reason
to how it turns out in the end. If both holes end up being centered on
both sides, it seems to be luck more then anything. There seemed to be
a lot of slop in the spindle on the drill, so I took that back and
tried a Ryobi... Worse. The run-out on it was so bad, I could see it
with the naked eye on just a 1/8" bit. When I rotated the bit 180
degrees and made an indentation, there was almost 1/32 of an inch space
between the two. Ridiculous. I can't believe there isn't even a decent
small bench press available nowadays, but that's a different story.

I've tried using short bits, center punching first, not center
punching, 1/16" pilot holes, a countersink for a starting point...
Nothing works. I've actually had better luck just drilling with a hand
drill, but that only works for the top hole... There's no chance at
getting the alignment right with bottom hole by had. I tried one of
those portable drill press stands, but it just wasn't precise enough.
Is there some kind of a portable drill guide I could use with a bushing
or something?

I'm kind of lost at this point... Am I really trying to do something
that can't be done without a mill? That's hard to believe. The actual
physical aspects of the holes is good... Nice and clean. It's just the
alignment I seem to have a problem with. I had no idea something that
seemed so simple would give me such grief. I have a lot more respect
for you metal heads now. Any ideas are welcome.

Thanks,

Dave

Dave:
Since you are working with such a thin wall on your tubing, I would
suggest trying a 1/4 inch end mill. You can chuck it up in your drill
press since it is hardened, it may slip if it hangs, but if you get a
center cutting one, it may resolve your problem. I would suggest a 4
flute end mill. If you can resolve the slop in the drill spindle, that
would help. I drill a lot of 2 inch square tubing for trailer hitches.
We use an annular cutter in a drill/mill. also, be sure you are not
drilling thru the side where the seam is. It is hardened and thicker
and will caouse drifting of your drill.

Sounds like you need to make a small fixture with a hardened drill
bushing to guide things. A drill bushing for a 1/4" bit will be about
3/8" to 1/2" in diameter by 1/4" to 1" long, commonly with a flange on
one end. In your case, use a longer one to get the guidance for the far
wall. These are replaceable when worn, run about $4 from
www.mcmaster.com (page 2423)

The fixture can be made of wood (hardwood) or metal (aluminum for short
runs, steel for long runs) Make a 3/4" square hole with a snug but not
binding fit. Mount the drill bushing on the top, drill away. If you need
to make many holes you can add a set of indexing holes along the base of
your fixture. You can keep alignment by clamping a block on the far end,
sliding it along the base. Visualize a 24" long piece of 1/2" by 4"
alumimum plate with the 3/4" clamp at one end, a row of holes down the
long end.

wrote:

I've worked with wood most of my life, but I'm not as experienced with
metals... I recently found that I have to do a project for work that
involves drilling multiple holes through both sides of 3/4"x 3/4" and
1/16 thick square aluminum tube to make antennas. Imagine a TV antenna
basically... There needs to be multiple matched holes along each tube,
and into those holes, 1/4" solid round will be inserted through both
sides. In other words, the holes on both sides of the tubing have to be
aligned pretty darn well, otherwise a slight misalignment will
translate to the 1/4" round being way off center by the time it gets to
the end... Which is about 1-2 feet long. There will be a tad bit of
wiggle room since the round will be attached by threads on the end, and
a nuts on both sides of the square tube, but not a whole lot.

I had no idea this would be so difficult. I went and got a Sears 9"
bench drill press and proceeded by clamping the tube into a press vise.
I figured once I had it lined up and centered, I could just slide the
tube down for each hole... Wrong. There seems to be no rhyme or reason
to how it turns out in the end. If both holes end up being centered on
both sides, it seems to be luck more then anything. There seemed to be
a lot of slop in the spindle on the drill, so I took that back and
tried a Ryobi... Worse. The run-out on it was so bad, I could see it
with the naked eye on just a 1/8" bit. When I rotated the bit 180
degrees and made an indentation, there was almost 1/32 of an inch space
between the two. Ridiculous. I can't believe there isn't even a decent
small bench press available nowadays, but that's a different story.

I've tried using short bits, center punching first, not center
punching, 1/16" pilot holes, a countersink for a starting point...
Nothing works. I've actually had better luck just drilling with a hand
drill, but that only works for the top hole... There's no chance at
getting the alignment right with bottom hole by had. I tried one of
those portable drill press stands, but it just wasn't precise enough.
Is there some kind of a portable drill guide I could use with a bushing
or something?

I'm kind of lost at this point... Am I really trying to do something
that can't be done without a mill? That's hard to believe. The actual
physical aspects of the holes is good... Nice and clean. It's just the
alignment I seem to have a problem with. I had no idea something that
seemed so simple would give me such grief. I have a lot more respect
for you metal heads now. Any ideas are welcome.

Thanks,

Dave

Can you purchase a bushing block to stabilize the drill bit prior to it
hitting the tube?

How many holes are we talking about for the whole project? 100, a million,
etc.

Joe - V#8013 - '86 VN750 - joe @ yunx .com
Northern, NJ
Ride a Motorcycle? Ask me about "The Ride"
http://www.youthelate.com/the_ride.htm

Born once - Die twice. Born twice - Die only once. Your choice...

Have unwanted music CDs or DVDs of any type? I can use them for our
charity. eMail me privately for details. Donation receipts available.

My eBay Stuff: http://tinyurl.com/4hpnc
wrote in message
oups.com...
I've worked with wood most of my life, but I'm not as experienced with
metals... I recently found that I have to do a project for work that
involves drilling multiple holes through both sides of 3/4"x 3/4" and
1/16 thick square aluminum tube to make antennas. Imagine a TV antenna
basically... There needs to be multiple matched holes along each tube,
and into those holes, 1/4" solid round will be inserted through both
sides. In other words, the holes on both sides of the tubing have to be
aligned pretty darn well, otherwise a slight misalignment will
translate to the 1/4" round being way off center by the time it gets to
the end... Which is about 1-2 feet long. There will be a tad bit of
wiggle room since the round will be attached by threads on the end, and
a nuts on both sides of the square tube, but not a whole lot.

I had no idea this would be so difficult. I went and got a Sears 9"
bench drill press and proceeded by clamping the tube into a press vise.
I figured once I had it lined up and centered, I could just slide the
tube down for each hole... Wrong. There seems to be no rhyme or reason
to how it turns out in the end. If both holes end up being centered on
both sides, it seems to be luck more then anything. There seemed to be
a lot of slop in the spindle on the drill, so I took that back and
tried a Ryobi... Worse. The run-out on it was so bad, I could see it
with the naked eye on just a 1/8" bit. When I rotated the bit 180
degrees and made an indentation, there was almost 1/32 of an inch space
between the two. Ridiculous. I can't believe there isn't even a decent
small bench press available nowadays, but that's a different story.

I've tried using short bits, center punching first, not center
punching, 1/16" pilot holes, a countersink for a starting point...
Nothing works. I've actually had better luck just drilling with a hand
drill, but that only works for the top hole... There's no chance at
getting the alignment right with bottom hole by had. I tried one of
those portable drill press stands, but it just wasn't precise enough.
Is there some kind of a portable drill guide I could use with a bushing
or something?

I'm kind of lost at this point... Am I really trying to do something
that can't be done without a mill? That's hard to believe. The actual
physical aspects of the holes is good... Nice and clean. It's just the
alignment I seem to have a problem with. I had no idea something that
seemed so simple would give me such grief. I have a lot more respect
for you metal heads now. Any ideas are welcome.

Thanks,

Dave

Why not get ahold of the traffic department where you live, and ask
them about buying a length of the pole they use to mount road signs?
Look around your neighborhood and you'll notice most of the traffic
signs are mounted on a piece of square tube that has holes every inch
on all four sides. It may be worth it to you to make some adjustments
in your project, materials, etc., to not have to drill all those holes.
Ronnie

I'll bet that in addition to the drill chuck being junk, the table is
not square with the spindle. If you did this in a bridgeport, it would
work fine, so it should in a good drill press. THink about finding a
good quality used drill press. An old delta, rockwell or some other,
with a real chuck and a sqare table.

I really like ht esears drill presses, but I alway replace the chuck ,
usually with a taiwanese albrecht clone

wrote:
I've worked with wood most of my life, but I'm not as experienced with
metals... I recently found that I have to do a project for work that
involves drilling multiple holes through both sides of 3/4"x 3/4" and
1/16 thick square aluminum tube to make antennas. Imagine a TV antenna
basically... There needs to be multiple matched holes along each tube,
and into those holes, 1/4" solid round will be inserted through both
sides. In other words, the holes on both sides of the tubing have to be
aligned pretty darn well, otherwise a slight misalignment will
translate to the 1/4" round being way off center by the time it gets to
the end... Which is about 1-2 feet long. There will be a tad bit of
wiggle room since the round will be attached by threads on the end, and
a nuts on both sides of the square tube, but not a whole lot.

I had no idea this would be so difficult. I went and got a Sears 9"
bench drill press and proceeded by clamping the tube into a press vise.
I figured once I had it lined up and centered, I could just slide the
tube down for each hole... Wrong. There seems to be no rhyme or reason
to how it turns out in the end. If both holes end up being centered on
both sides, it seems to be luck more then anything. There seemed to be
a lot of slop in the spindle on the drill, so I took that back and
tried a Ryobi... Worse. The run-out on it was so bad, I could see it
with the naked eye on just a 1/8" bit. When I rotated the bit 180
degrees and made an indentation, there was almost 1/32 of an inch space
between the two. Ridiculous. I can't believe there isn't even a decent
small bench press available nowadays, but that's a different story.

I've tried using short bits, center punching first, not center
punching, 1/16" pilot holes, a countersink for a starting point...
Nothing works. I've actually had better luck just drilling with a hand
drill, but that only works for the top hole... There's no chance at
getting the alignment right with bottom hole by had. I tried one of
those portable drill press stands, but it just wasn't precise enough.
Is there some kind of a portable drill guide I could use with a bushing
or something?

I'm kind of lost at this point... Am I really trying to do something
that can't be done without a mill? That's hard to believe. The actual
physical aspects of the holes is good... Nice and clean. It's just the
alignment I seem to have a problem with. I had no idea something that
seemed so simple would give me such grief. I have a lot more respect
for you metal heads now. Any ideas are welcome.

Thanks,

Dave

It's tough to get better than about +/- 0.015" accuracy when locating
holes with a center punch and drill press. The slop in the quill
bearings, chuck, table, and the starting point of the drill all add up
pretty quick, as you found out.

If you need better accuracy than that, you'll have to build a jig and
spot-drill each hole before going in with the bigger bit. Of find a
cheap milling machine -- almost anything will have better rigidity and
accuracy than what you're using now.


wrote:



I had no idea this would be so difficult. I went and got a Sears 9"
bench drill press and proceeded by clamping the tube into a press vise.
I figured once I had it lined up and centered, I could just slide the
tube down for each hole... Wrong. There seems to be no rhyme or reason
to how it turns out in the end. If both holes end up being centered on
both sides, it seems to be luck more then anything. There seemed to be
a lot of slop in the spindle on the drill, so I took that back and
tried a Ryobi... Worse. The run-out on it was so bad, I could see it
with the naked eye on just a 1/8" bit. When I rotated the bit 180
degrees and made an indentation, there was almost 1/32 of an inch space
between the two. Ridiculous. I can't believe there isn't even a decent
small bench press available nowadays, but that's a different story.

.... the holes on both sides of the tubing have to be
aligned pretty darn well, ...

.... works for the top hole... There's no chance at
getting the alignment right with bottom hole ...

I must be missing something here. As I understand it, you need to have
holes on opposite sides of the tube aligned. It seems obvious that you
would just start at the top and continue through the other side. That
it seems so obvious is why I think that I must be missing something.
What is it?

The other part is how the series of holes down the length of the tube
are aligned. There are 2 parts: how far apart they are and how closely
they are to a straight line. You need to quantify both of these. E.g.,
they have to be 1" apart +- 1/32 and they need to be within a 1/32 of a
line. A 1/32 was just an example, but your being a woodworker and not
having much metalworking experience, 1/32 would be a realistic goal. If
it needs to be much better than that, you'll probably need some help.

If 1/32 is good enough, a simple jig should get you there. Let us know
and I'll go into it more.

Bob

BTW - you're in luck using aluminum - it works more like wood than it
does steel.

On 29 Jan 2005 10:02:00 -0800, the inscrutable "Ronnie"
spake:

Why not get ahold of the traffic department where you live, and ask
them about buying a length of the pole they use to mount road signs?
Look around your neighborhood and you'll notice most of the traffic
signs are mounted on a piece of square tube that has holes every inch
on all four sides. It may be worth it to you to make some adjustments
in your project, materials, etc., to not have to drill all those holes.
Ronnie

Has anyone here EVER successfully purchased anything from "the city"
or "the county"? All I've ever heard was "We're not set up to do
that." Of course, I haven't tried the "bribing the lone workman with
cold beverages ploy" yet, either.


================================================== ======
TANSTAAFL: There ain't no such thing as a free lunch.
http://diversify.com Gourmet Web Applications
==========================

wrote in news:1106983013.521991.220000
@z14g2000cwz.googlegroups.com:

I've worked with wood most of my life, but I'm not as experienced with
metals... I recently found that I have to do a project for work that
involves drilling multiple holes through both sides of 3/4"x 3/4" and
1/16 thick square aluminum tube to make antennas. Imagine a TV antenna
basically... There needs to be multiple matched holes along each tube,
and into those holes, 1/4" solid round will be inserted through both
sides. In other words, the holes on both sides of the tubing have to be
aligned pretty darn well, otherwise a slight misalignment will
translate to the 1/4" round being way off center by the time it gets to
the end... Which is about 1-2 feet long. There will be a tad bit of
wiggle room since the round will be attached by threads on the end, and
a nuts on both sides of the square tube, but not a whole lot.

I had no idea this would be so difficult. I went and got a Sears 9"
bench drill press and proceeded by clamping the tube into a press vise.
I figured once I had it lined up and centered, I could just slide the
tube down for each hole... Wrong. There seems to be no rhyme or reason
to how it turns out in the end. If both holes end up being centered on
both sides, it seems to be luck more then anything. There seemed to be
a lot of slop in the spindle on the drill, so I took that back and
tried a Ryobi... Worse. The run-out on it was so bad, I could see it
with the naked eye on just a 1/8" bit. When I rotated the bit 180
degrees and made an indentation, there was almost 1/32 of an inch space
between the two. Ridiculous. I can't believe there isn't even a decent
small bench press available nowadays, but that's a different story.

I've tried using short bits, center punching first, not center
punching, 1/16" pilot holes, a countersink for a starting point...
Nothing works. I've actually had better luck just drilling with a hand
drill, but that only works for the top hole... There's no chance at
getting the alignment right with bottom hole by had. I tried one of
those portable drill press stands, but it just wasn't precise enough.
Is there some kind of a portable drill guide I could use with a bushing
or something?

I'm kind of lost at this point... Am I really trying to do something
that can't be done without a mill? That's hard to believe. The actual
physical aspects of the holes is good... Nice and clean. It's just the
alignment I seem to have a problem with. I had no idea something that
seemed so simple would give me such grief. I have a lot more respect
for you metal heads now. Any ideas are welcome.


If you're pretty good at wood working, this should be a pretty easy fix.
Build a jig out of wood. Use a good quality hardwood board to make a base
to which you will attach a fence. Next drill a 1/4" hole so that the center
is precisely 3/8" from the fence, drill another that is spaced the same
distance that you want the holes spaced on the tube., this hole will be
used for a dowel pin that will determine the linear spacing of the holes. I
would drill the holes first, then locate the fence by inserting a 1/4 inch
pin in the holes then placing a 1/4" piece of flat stock between the pins
and the fence. Instead of just using 3/8", I would measure the tubing and
divide by two and locate the center of the hole at that dimension. Now
clamp the jig to the table of the drill press. Locate the inside hole in
line with the spindle of the drill press. The easiest way to do this is to
insert the pin in the hole and then chuck on it with the drill chuck. Allow
the jig to float to the center of the drill chuck. After you drill your
first hole you are going to put a pin in the second hole and put the
previously drilled hole over it to give you the linear spacing. Now drill
the hole in the tube as follows: Locate the first hole by measuring, clamp
the tube to the base and the fence. You should be able to use "Quick
Clamps". Get a combination drill and countersink otherwise known as a
center drill. Start the hole by drilling with this bit so that the
countersink is just slightly larger than 1/4". Change bits to the 1/4"
drill and drill through one side only. Now unclamp the tube and insert the
pin in the hole located under the spindle. Flip the tube over putting the
previously drilled hole over the pin. Repeat, drilling with the center
drill and drill. If the mis-alignment is no good either adjust the jig or
if being exactly in the center of the tube isn't very important, flip the
tube and rotate it end for end. For the second and subsequent holes insert
the second pin and use it to locate for precise spacing between holes. You
need to minimize the drill runout if you can. If you can't, try using a
small trepanning tool, or a two flute end mill instead of the drills.

Hope you can understand what I'm trying to describe.
Good luck,

Dan

On Sat, 29 Jan 2005 19:54:54 -0800, Larry Jaques
wrote:

On 29 Jan 2005 10:02:00 -0800, the inscrutable "Ronnie"
spake:

Why not get ahold of the traffic department where you live, and ask
them about buying a length of the pole they use to mount road signs?
Look around your neighborhood and you'll notice most of the traffic
signs are mounted on a piece of square tube that has holes every inch
on all four sides. It may be worth it to you to make some adjustments
in your project, materials, etc., to not have to drill all those holes.
Ronnie

Has anyone here EVER successfully purchased anything from "the city"
or "the county"? All I've ever heard was "We're not set up to do
that." Of course, I haven't tried the "bribing the lone workman with
cold beverages ploy" yet, either.


================================================= =======
TANSTAAFL: There ain't no such thing as a free lunch.
http://diversify.com Gourmet Web Applications
==========================

Purchase? No. But a lot of the time the workmen will give you small
stuff for free. Ask in the yard, not the front office.

--RC
"Sometimes history doesn't repeat itself. It just yells
'can't you remember anything I've told you?' and lets
fly with a club.
-- John W. Cambell Jr.

It is a no brainier if the tube was centered under the drill.
If it is not - then a slight off center hole through the wall
wouldn't show up as defective as much.

Seems if that is the issue - maybe drill through isn't possible -
then a JIG is the way again - drill one side as needed.

Now have a jig with a pin. the jig holds the tube firmly and the pin
slides into the hole with a sliding fit. Just have the pin centered
under the drill and you are set.

Martin

Bob Engelhardt wrote:

... the holes on both sides of the tubing have to be

aligned pretty darn well, ...


... works for the top hole... There's no chance at

getting the alignment right with bottom hole ...


I must be missing something here. As I understand it, you need to have
holes on opposite sides of the tube aligned. It seems obvious that you
would just start at the top and continue through the other side. That
it seems so obvious is why I think that I must be missing something.
What is it?

The other part is how the series of holes down the length of the tube
are aligned. There are 2 parts: how far apart they are and how closely
they are to a straight line. You need to quantify both of these. E.g.,
they have to be 1" apart +- 1/32 and they need to be within a 1/32 of a
line. A 1/32 was just an example, but your being a woodworker and not
having much metalworking experience, 1/32 would be a realistic goal. If
it needs to be much better than that, you'll probably need some help.

If 1/32 is good enough, a simple jig should get you there. Let us know
and I'll go into it more.

Bob

BTW - you're in luck using aluminum - it works more like wood than it
does steel.


--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

Has anyone here EVER successfully purchased anything from "the city"
or "the county"? All I've ever heard was "We're not set up to do
that." Of course, I haven't tried the "bribing the lone workman with
cold beverages ploy" yet, either.

Purchased, no... But I've got friends there and I've acquired some
decomissioned stuff for the price of a question...

Regards,
Joe Agro, Jr.
http://www.autodrill.com
http://www.multi-spindle-heads.com

V8013

My eBay: http://tinyurl.com/3n8gj

Those are all good suggestions guys, thanks. As to the idea of the
table being off square, that was the first thing I checked. So it
wasn't that. But I did end up building a jig as suggested, and it helps
a lot. But as a side note... I noticed Harbor Freight had it's little
press on sale for a ridiculous 39.95 this week. I had absolutely no
expectations, since I tried two presses that were more, with poor
results. But I figured for $39.95, what did I have to lose. If it
didn't work, I was going to give it to a friend... Well, guess what...
Not only is it better quality then the two over $100 presses I tried,
but it seems to drill straight. Go figure. Maybe I just had bad luck
with the others.

Thanks for the help,

Dave

wrote:
I've worked with wood most of my life, but I'm not as experienced
with
metals... I recently found that I have to do a project for work that
involves drilling multiple holes through both sides of 3/4"x 3/4" and
1/16 thick square aluminum tube to make antennas. Imagine a TV
antenna
basically... There needs to be multiple matched holes along each
tube,
and into those holes, 1/4" solid round will be inserted through both
sides. In other words, the holes on both sides of the tubing have to
be
aligned pretty darn well, otherwise a slight misalignment will
translate to the 1/4" round being way off center by the time it gets
to
the end... Which is about 1-2 feet long. There will be a tad bit of
wiggle room since the round will be attached by threads on the end,
and
a nuts on both sides of the square tube, but not a whole lot.

much snippage

Dave

Since you work with wood, do you happen to have one of those
self-centering dowling jigs? Like this:
http://www.woodcraft.com/family.aspx?familyid=782

Mine's a lot older and uses cast clamping jaws instead of extrusions,
but I use it periodically for putting in centered cross-holes where a
drill press would be hard to use. If you've got one, give it a whirl.
Try those piloted sheetmetal bits, too("Bullet bits"). Spacing your
holes might be a problem, but not unsolvable.

Stan