Hello Group.

I am an amatuer metalworker and have a question about drilling holes through
thinwalled tubing (.035 to .049") so that the hole goes through
perpendicular to the longitudinal axis? I have a "V" block and a drill
press. I read that it isn't a good practice to drill all the way through a
tube and that it is better to drill one hole, rotate the tube 180 degreees
and drill the opposite hole with a final reaming to correct finished
diameter. My problem is how do I mark the tube and center punch it to get
the holes are directly opposite each other? Thanks in advance.

--
John "Ebby" Ebensperger
Hatz Classic s/n37
Camden, NY

Ebby wrote:

Hello Group.

I am an amatuer metalworker and have a question about drilling holes through
thinwalled tubing (.035 to .049") so that the hole goes through
perpendicular to the longitudinal axis? I have a "V" block and a drill
press. I read that it isn't a good practice to drill all the way through a
tube and that it is better to drill one hole, rotate the tube 180 degreees
and drill the opposite hole with a final reaming to correct finished
diameter. My problem is how do I mark the tube and center punch it to get
the holes are directly opposite each other? Thanks in advance.



Perhaps you can drill all the way through with a small pilot drill and
then do the larger size hole from each side. that is my quess.

Thetinkerer
Web: http://thetinkerer.baz.net.au/

I am an amatuer metalworker and have a question about drilling holes
through
thinwalled tubing (.035 to .049") so that the hole goes through
perpendicular to the longitudinal axis? I have a "V" block and a drill
press. I read that it isn't a good practice to drill all the way through
a
tube and that it is better to drill one hole, rotate the tube 180 degreees
and drill the opposite hole with a final reaming to correct finished
diameter. My problem is how do I mark the tube and center punch it to get
the holes are directly opposite each other? Thanks in advance.

When drilling through a tube, the most common problem people have is that
the drill bit wants to "walk" off center because the tube is round... An
easy fix is to center punch a good large mark so the drill can't walk to
either side then use the V-Block and drill away, etc.

If the bit is large enough, you may need to drill a smaller pilot hole
first.

The real "professional" answer is one of two other ways...

1. Use a drill bushing near the piece so the bit cannot flex.

2. Use two drills simultaneously on the same pipe - one from the top and one
from the bottom. I just sold a system to a customer to do exactly this. It
doesn't sound like your production is large enough to justify this, but if
you (or anyone) wants a picture of this machine, I can eMail it to you.
Just let me know.

Extra Credit - Hougen makes a "hole saw" type bit that has a pointed center
guide which is spring loaded. When it hits the pipe or flat surface, it
digs in a bit and keeps the circular part of the bit centered on the pipe.
When it breaks through, the spring loaded center pops the "slug" out. It
only works on larger diameter pipe or tube though. Smaller pipe has too
much of a curve.

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

V8013

"Ebby" wrote in message
...
Hello Group.

I am an amatuer metalworker and have a question about drilling holes
through
thinwalled tubing (.035 to .049") so that the hole goes through
perpendicular to the longitudinal axis? I have a "V" block and a drill
press. I read that it isn't a good practice to drill all the way through
a
tube and that it is better to drill one hole, rotate the tube 180 degreees
and drill the opposite hole with a final reaming to correct finished
diameter. My problem is how do I mark the tube and center punch it to get
the holes are directly opposite each other? Thanks in advance.

--
John "Ebby" Ebensperger
Hatz Classic s/n37
Camden, NY



Since you are only using a drill press, I assume your precision requirements
are minimal so this might work. Set up the drill to just clear the vee and
drill a hole the same size as the hole you want in the tube into a chunk of
something. Now put your tube into the drill press and drill one side.
remove the tube and put a pin into the hole in the block. Now set the tube
back into the vee block with the hole fit over the pin. This will index the
next hole 180 degrees from the first.

Another way is to get a compression fitting and clamp it on to your tube.
Now you can place the nut into the vise and then you can index the second
hole easy.

To mark a line around the circumference of the tube, use your tubing cutter
to lightly scribe the line.

You also might find that using split point drill bits will help prevent the
bit from walking as much as regular bits. If the tubing is brass or
aluminum, you might cheat and use a brad point bit.

Good luck.

--

Roger Shoaf

About the time I had mastered getting the toothpaste back in the tube, then
they come up with this striped stuff.

I had to drill a lot of holes in copper tube when I was making model
boilers. I took a piece of bar stock about 6" long, 1" wide and about twice
as thick as the tube diameter and drilled a hole just large enough to slip
the tube through. Then drilled a crossing hole centered on the first and on
the 1" side to fit a pilot drill. Clamped the bar to the drill press table,
marked the tubes 1/2" from the desired hole location, sliped the tube into
the block until the mark lined up with the edge and drilled through.
--
Glenn Ashmore


I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Ebby" wrote in message
...
Hello Group.

I am an amatuer metalworker and have a question about drilling holes
through
thinwalled tubing (.035 to .049") so that the hole goes through
perpendicular to the longitudinal axis? I have a "V" block and a drill
press. I read that it isn't a good practice to drill all the way through
a
tube and that it is better to drill one hole, rotate the tube 180 degreees
and drill the opposite hole with a final reaming to correct finished
diameter. My problem is how do I mark the tube and center punch it to get
the holes are directly opposite each other? Thanks in advance.

--
John "Ebby" Ebensperger
Hatz Classic s/n37
Camden, NY

Sorry, this is bad advice. This fellow is building an airplane and you
don't want any scribe lines that could promote cracking.

Ed Angell

"Roger Shoaf" wrote in message
...

"Ebby" wrote in message
...
Hello Group.

I am an amatuer metalworker and have a question about drilling holes
through
thinwalled tubing (.035 to .049") so that the hole goes through
perpendicular to the longitudinal axis? I have a "V" block and a drill
press. I read that it isn't a good practice to drill all the way
through
a
tube and that it is better to drill one hole, rotate the tube 180
degreees
and drill the opposite hole with a final reaming to correct finished
diameter. My problem is how do I mark the tube and center punch it to
get
the holes are directly opposite each other? Thanks in advance.

--
John "Ebby" Ebensperger
Hatz Classic s/n37
Camden, NY



Since you are only using a drill press, I assume your precision
requirements
are minimal so this might work. Set up the drill to just clear the vee
and
drill a hole the same size as the hole you want in the tube into a chunk
of
something. Now put your tube into the drill press and drill one side.
remove the tube and put a pin into the hole in the block. Now set the
tube
back into the vee block with the hole fit over the pin. This will index
the
next hole 180 degrees from the first.

Another way is to get a compression fitting and clamp it on to your tube.
Now you can place the nut into the vise and then you can index the second
hole easy.

To mark a line around the circumference of the tube, use your tubing
cutter
to lightly scribe the line.

You also might find that using split point drill bits will help prevent
the
bit from walking as much as regular bits. If the tubing is brass or
aluminum, you might cheat and use a brad point bit.

Good luck.

--

Roger Shoaf

About the time I had mastered getting the toothpaste back in the tube,
then
they come up with this striped stuff.

Sorry, this is bad advice. This fellow is building an airplane and you
don't want any scribe lines that could promote cracking.

If this is true, he really wants to go out and buy a drill bushing to guide
the bit precisely. He also wants to make sure that bit is as short as
possible but still long enough to gon through thee entire tube to minimize
any flex at all.

Then again, a drill press isn't the right machine to be using (unless it is
a monster with a nice stable table) either.

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

V8013

While using an edge finder is probably the most accurate method of centering a
hole on a cylinder, it requires a graduated table feed.

A quick and dirty way is a modification of the method a lot of us use to set
lathe bits on center. Use a pointed mandrel in the drill chuck and a thin rule
or piece of flat stock between it and the target. When the rule is level, the
spindle is on center.

John Martin

A lot depends on what you want for precision on both location and hole
size, also the ratios of your cross hole to the tubing size. If you
want about a 1" hole in a 12" pipe, use a hole saw. If you want a
1.000" hole in 1 1/2" tube located exactly on the centerline, you're
going to want some kind of a jig and drill bushing setup and a heavy
drill press or mill, plus drill under-sized and ream up. The bigger
the hole compared to the size of the tubing, the more problems you're
going to have drilling the hole with standard bits. When you start
getting to the point where the outer tips of the drill flutes are
hitting the sides of the tubing before the point hits the opposite side
of the tubing, you're in trouble and need to do things another way.
One way is to drill clear through with a small bit, then drill each
side from the outside with the large one. When you start putting large
holes through tubing, those spots become very weak, something to
consider if it's going to be a load-bearing frame or something like
that.

Stan

In qnGtd.157822$V41.21698@attbi_s52, on 12/08/04
at 04:56 PM, "Ed Angell" said:

Sorry, this is bad advice. This fellow is building an airplane

How do you know the OP's building an aeroplane? He doesn't mention it in
his post?

-----------------------------------------------------------------------------------------------------
John Lloyd - Cymru/Wales

-----------------------------------------------------------------------------------------------------

Take a look at his email address, he's building a Hatz Biplane and is pretty
proud of it.

Ed Angell

wrote in message
ernet.com...
In qnGtd.157822$V41.21698@attbi_s52, on 12/08/04
at 04:56 PM, "Ed Angell" said:

Sorry, this is bad advice. This fellow is building an airplane

How do you know the OP's building an aeroplane? He doesn't mention it in
his post?

--------------------------------------------------------------------------
---------------------------
John Lloyd - Cymru/Wales

--------------------------------------------------------------------------
---------------------------

Hello Group,

For the record I am building an airplane and know not to scribe marks in
metal. I use a silver pencil, pencil or sharpie marker what ever is
closest. I am curious though about a couple posts regarding my use of a
drill press to drill holes as not being the correct tool. What is the
recommended or better tool for this type of operation. The tubing I am
using is 4130 steel tubing 1 1/2" or less in diameter and .065" down to
..035" in wall thickness. Two more items, what is a drill bushing and
finally I believe I need to get some sort of reference book on machining
techniques. I am open to suggestions.

Thanks
Ebby

On Wed, 8 Dec 2004 12:06:41 -0500, "Joe AutoDrill"
wrote:

Sorry, this is bad advice. This fellow is building an airplane and you
don't want any scribe lines that could promote cracking.

If this is true, he really wants to go out and buy a drill bushing to guide
the bit precisely. He also wants to make sure that bit is as short as
possible but still long enough to gon through thee entire tube to minimize
any flex at all.

Then again, a drill press isn't the right machine to be using (unless it is
a monster with a nice stable table) either.

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

V8013

Drill through with the shortest small diameter bit that will do the
job, then put in the big bit and drill through one side, flip, and
finish.