I have a piece of 1", 1/8" aluminum angle iron that is 18" long and 1/8"
thick. I want to drill sixteen holes in it, in a straight line, each hole 1"
away from the other. I also have a flat piece of aluminum that is 2" x 18" x
1/8" thick. I want to drill two rows of 16 holes in that one. All holes are
1/4" in diameter.

I've scrapped enough metal to set my ego aside and admit that I need help
with the very basics of basics. How do I make the measurements, mark them,
and then drill the holes?

Thanks!

Daven Thrice writes:

I've scrapped enough metal to set my ego aside and admit that I need
help with the very basics of basics. How do I make the measurements,
mark them, and then drill the holes?

Straightedge and carbide scriber for the lines. ($20)

Digital calipers' points as compass points to cross-scribe the intervals.
($20)

Spring-loaded center punch to dimple the points to drill. ($3)

Let the dimples center the drill bit.

Should be accurate to a few thou or 0.01" depending on your skills.

A loupe helps.

Daven Thrice wrote:
I have a piece of 1", 1/8" aluminum angle iron that is 18" long and 1/8"
thick. I want to drill sixteen holes in it, in a straight line, each hole 1"
away from the other. I also have a flat piece of aluminum that is 2" x 18" x
1/8" thick. I want to drill two rows of 16 holes in that one. All holes are
1/4" in diameter.

I've scrapped enough metal to set my ego aside and admit that I need help
with the very basics of basics. How do I make the measurements, mark them,
and then drill the holes?

Thanks!

On a vertical mill. A piece of cake. :-)
...lew...

I have a piece of 1", 1/8" aluminum angle iron that is 18" long and 1/8"
thick. I want to drill sixteen holes in it, in a straight line, each hole 1"
away from the other. I also have a flat piece of aluminum that is 2" x 18" x
1/8" thick. I want to drill two rows of 16 holes in that one. All holes are
1/4" in diameter.

I've scrapped enough metal to set my ego aside and admit that I need help
with the very basics of basics. How do I make the measurements, mark them,
and then drill the holes?

Thanks!



Don't know what size holes you want to drill, but you can make a jig
(accurate as you possibly can) by drilling your first hole, then
moving over the required distance and drilling the second hole at the
correct position. Then put a pin in the first hole that sticks up
enough so that when you drill the first hole in the angle at the
correct starting point, you would then lift it up and place the just
drilled hole over the "pin" in the jig, which will locate the angle
for the next hole. Drill it, then shift the angle over again using
the pin as the locator for the entire series of holes.
Ken.

In article mu81d.259560$sh.198210@fed1read06, Daven Thrice says...

I have a piece of 1", 1/8" aluminum angle iron that is 18" long and 1/8"
thick. I want to drill sixteen holes in it, in a straight line, each hole 1"
away from the other. I also have a flat piece of aluminum that is 2" x 18" x
1/8" thick. I want to drill two rows of 16 holes in that one. All holes are
1/4" in diameter.

I've scrapped enough metal to set my ego aside and admit that I need help
with the very basics of basics. How do I make the measurements, mark them,
and then drill the holes?

Do the holes in the two pieces have to line up with anything
in particular?

Basically you need to decide in adavance what tolerance you want on the
hole location.

If it's sub-thousanth of an inch, you need to find a jig borer.

If it's +/- 1/16 inch, you can do it with a good tape measure.

Nobody can really answer your question with any decent answer
until you come across with the tolerance for your parts.

Jim


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"jim rozen" wrote in message
...
In article mu81d.259560$sh.198210@fed1read06, Daven Thrice says...

I have a piece of 1", 1/8" aluminum angle iron that is 18" long and 1/8"
thick. I want to drill sixteen holes in it, in a straight line, each hole
1"
away from the other. I also have a flat piece of aluminum that is 2" x 18"
x
1/8" thick. I want to drill two rows of 16 holes in that one. All holes
are
1/4" in diameter.

I've scrapped enough metal to set my ego aside and admit that I need help
with the very basics of basics. How do I make the measurements, mark them,
and then drill the holes?

Do the holes in the two pieces have to line up with anything
in particular?

Basically you need to decide in adavance what tolerance you want on the
hole location.

If it's sub-thousanth of an inch, you need to find a jig borer.

If it's +/- 1/16 inch, you can do it with a good tape measure.

Nobody can really answer your question with any decent answer
until you come across with the tolerance for your parts.

Jim,

Is there a tolerance that one associates with a line that is supposed to be
visibly straight? I'm going to screw connectors into all of those holes, and
if somebody looks at those connectors, I want them to be in a straight line.

There is another perspective, too. What can I get in terms of accuracy with
a drill press and the tools that Richard Kinch suggested?

Thanks,

Daven

It all depends on the degree of accuracy that you require. I have
found that the holes in pegboard (Masonite with holes in it) are
suprisingly accurate and can be used as a template provided the
spacing works for you. I think that 1" spacing is standard but be sure
to check.

Harold
Winnipeg, Canada

"Daven Thrice" wrote in message news:mu81d.259560$sh.198210@fed1read06...
I have a piece of 1", 1/8" aluminum angle iron that is 18" long and 1/8"
thick. I want to drill sixteen holes in it, in a straight line, each hole 1"
away from the other. I also have a flat piece of aluminum that is 2" x 18" x
1/8" thick. I want to drill two rows of 16 holes in that one. All holes are
1/4" in diameter.

I've scrapped enough metal to set my ego aside and admit that I need help
with the very basics of basics. How do I make the measurements, mark them,
and then drill the holes?

Thanks!

In article yQi1d.262818$sh.77071@fed1read06, Daven Thrice says...

Is there a tolerance that one associates with a line that is supposed to be
visibly straight? I'm going to screw connectors into all of those holes, and
if somebody looks at those connectors, I want them to be in a straight line.

There is another perspective, too. What can I get in terms of accuracy with
a drill press and the tools that Richard Kinch suggested?

When I do stuff like this, I blue the part up around where the holes are
going to go, and use my dial caliper as a scratch gage to scribe a
line a set distance away from the edge of the part. Basically you
just open up the caliper, lock the setting, and place one jaw on
the edge, the other jaw is pressed against the surface of the part
and then you slide it along the edge to make a line.

Then you can use the same caliper to step off the holes.

Once you have the crosses marked out, take a sharp starrett
center punch and carefully pop each intersection. If you
then drill with a sharp pilot drill (I don't bother with
centerdrilling stuff like this) it will pick up the centerpunch
mark nicely.

Then go back and open them all up to 1/4 inch. What are these,
SMA connectors?

Doing it this way will pass the 'looks OK' test but in terms
of numbers, you will be +/- 0.005 inch on location that way
if you practice a few times.

If you need better than that, because it's a production job
being delivered to a customer, then you probably need to
do it on a bridgeport.

Jim


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==================================================
please reply to:
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==================================================

As others have said, it all depends ...

Many years ago I bought an optical center-punch - basically a gadget that
allows you to place a center punch mark exactly on a scribed line. For
something like this operation I would start at one end, scribe a line the
entire length. Then start with a cross mark at one end, center punch it,
then use that center punch with a pair of compasses to mark the next
crossing, etc. One down side of this method is that if the hole/hole spacing
is not exactly correct, then the end holes will be somewhat out of position.
If you need absolute accuracy (means that each hole must go in the correct
place +- some tolerance), then make all hole position measurements from one
end instead.

Drilling is just as important as marking. If the drill bit you use is larger
across the chisel end than the size of your center punch, the drill will
wander. Far better to use a proper center drill, whose end comes to a point
and therefore locates precisely in the center punch mark. Once you have a
center hole started, use an ordinary drill. If you cannot get accurate hole
positions even so, then bear in mind that a possible cause is poor quality
or badly sharpened drills.

If you want the sets of holes in the separate pieces of metal to line up,
clamp them together before drilling ... (or use one as a jig to line up the
other holes).

D

"Daven Thrice" wrote in message
news:mu81d.259560$sh.198210@fed1read06...
I have a piece of 1", 1/8" aluminum angle iron that is 18" long and 1/8"
thick. I want to drill sixteen holes in it, in a straight line, each hole
1"
away from the other. I also have a flat piece of aluminum that is 2" x 18"
x
1/8" thick. I want to drill two rows of 16 holes in that one. All holes
are
1/4" in diameter.

I've scrapped enough metal to set my ego aside and admit that I need help
with the very basics of basics. How do I make the measurements, mark them,
and then drill the holes?

Thanks!






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"Dave Garnett" wrote:

Drilling is just as important as marking. If the drill bit you use is
larger
across the chisel end than the size of your center punch, the drill will
wander. Far better to use a proper center drill, whose end comes to a
point
and therefore locates precisely in the center punch mark.

In addition, I think I need to push the small bit way up into the chuck so
that its stiff. Yesterday when I was drilling holes, I watched the small bit
I was using to drill pilot holes dance around on the metal. Another thing I
did, which must have been stupid, is to put a drop of oil on the
centerpunched hole before I started drilling. That makes it hard to see the
hole and line up the bit.

If you want the sets of holes in the separate pieces of metal to line up,
clamp them together before drilling ... (or use one as a jig to line up
the
other holes).

Sounds like a work saver, OR a way to scrap several pieces of metal at one
time :-)

Thanks -- Daven

"Richard J Kinch" wrote


Straightedge and carbide scriber for the lines. ($20)

OK, I'm working with 1" extrusions, that are 90 deg. angles. I want to mark
a hole that is 1/4" in from one edge. The only "straight edge" I can think
of using is a metal ruler, which is an 1" wide (or so). I'm wondering how to
clamp the ruler to the work piece good enough for me to be able to drag that
scribe along the straight edge without the straight edge shifting.

I have one of those laser straight line things that you use for a level. I'm
thinking about taping the work piece to the wall and using the laser level
to create a straight line. Hmmm. Don't know if that will work. If it does,
though, I can then tape a ruler just below the straight line and then mark
of X's, which can then be center punched. This sounds like a lot to go
through, though. I'd rather just clamp a straight edge to the aluminum, but
how is that properly done?

"Daven Thrice" wrote in message
news:9Ik1d.263527$sh.202086@fed1read06...

"Richard J Kinch" wrote


Straightedge and carbide scriber for the lines. ($20)

OK, I'm working with 1" extrusions, that are 90 deg. angles. I want to
mark
a hole that is 1/4" in from one edge. The only "straight edge" I can think
of using is a metal ruler, which is an 1" wide (or so). I'm wondering how
to
clamp the ruler to the work piece good enough for me to be able to drag
that
scribe along the straight edge without the straight edge shifting.

I have one of those laser straight line things that you use for a level.
I'm
thinking about taping the work piece to the wall and using the laser level
to create a straight line. Hmmm. Don't know if that will work. If it does,
though, I can then tape a ruler just below the straight line and then mark
of X's, which can then be center punched. This sounds like a lot to go
through, though. I'd rather just clamp a straight edge to the aluminum,
but
how is that properly done?

Clamp a piece of straight stock to the drill press table as a fence to keep
the holes in line. If you want to, put a tape measure on the straight edge
so you can advance the angle in 1" increments.

Check out any woodworkers group about drilling holes for shelving for more
ideas..

On Mon, 13 Sep 2004 10:22:44 -0700, "Daven Thrice" wrote:

||
||"Richard J Kinch" wrote
||
||
|| Straightedge and carbide scriber for the lines. ($20)
||
||OK, I'm working with 1" extrusions, that are 90 deg. angles. I want to mark
||a hole that is 1/4" in from one edge. The only "straight edge" I can think
||of using is a metal ruler, which is an 1" wide (or so). I'm wondering how to
||clamp the ruler to the work piece good enough for me to be able to drag that
||scribe along the straight edge without the straight edge shifting.

Just use that, or the dial-caliper-as scribe method

||I have one of those laser straight line things that you use for a level.

The metal rule is at least as accurate and a lot less trouble.
Texas Parts Guy

A few suggestions, most which have been given in one form or another:

Layout 1/4 inch from edge... Go to local industrial supply house and
purchase
a 1/4 inch square HSS tool bit. Sharpen end (90 degrees to length) to make
as sharp an edge as possible. Then clamp your angle firmly on a flat
surface
so that your reference edge is against same surface. Then simply run the
tool
bit along the length you want the holes. Press hard enough to score deep
enough so that when you center punch it, you can "feel" the score before
hitting
the punch.

Locate the first hole using an accurate scale. (Might consider getting
what's called
a square head, which you can adjust the scale itself to the dimension, then
mark
at the end of the scale.) For evenly spaced holes, get a good set of
dividers
and set the distance accurately. (I like to let the points "rest" in the
graduations of
the scale) Then step off the distance and use one leg of the divider to
scribe
across the first line, again pressing hard enough to make a good score which
you
can later feel. A little practice and it goes pretty quick.

Invest (or make) what is known as a "prick punch", and lightly prick punch
the
locations you've just laid out. Here is where you develop the feel for being
within
both score marks! Then visually check the prick punch. Not quite there?
Slant
the punch and put just at edge of 1st mark and "move" it by hitting at an
angle.
Again, a little practice helps, but it can be done.

Once all of the prick punches are to your liking, follow up with a properly
pointed center punch, holding it as square with the work as possible. It
also
helps to use a good quality ball peen hammer, striking the the punch as
square
as you can.

Now consider that alum. is relatively soft, so if a drill is not exactly
over the punch
mark, it is likely to not follow the point you have made. Hence the idea of
a smaller
drill (I like to use 1/16 inch or less) which will flex enough to go into
the center punched
position. Drill about 1/16 inch deep. Now visually examine the positions
again, mostly
to see how good you are. (A badly misplaced hole can still be moved, but
that's anothe
post?)

Now follow up with a center drill, and drill deep enough that the
countersink dia.
is slightly larger than your drill (say about 1/64 larger), and finally
drill though with desired
drill size.

The above can yield holes within .005-.015 inches with reasonble care. Skip
some of the
steps if not this is not required. By the way, tolerances for holes
locations are usally to
the center lines from some reference surface/edge/other hole.



"Daven Thrice" wrote in message
news:9Ik1d.263527$sh.202086@fed1read06...

"Richard J Kinch" wrote


Straightedge and carbide scriber for the lines. ($20)

OK, I'm working with 1" extrusions, that are 90 deg. angles. I want to
mark a hole that is 1/4" in from one edge. The only "straight edge" I can
think of using is a metal ruler, which is an 1" wide (or so). I'm
wondering how to clamp the ruler to the work piece good enough for me to
be able to drag that scribe along the straight edge without the straight
edge shifting.

I have one of those laser straight line things that you use for a level.
I'm thinking about taping the work piece to the wall and using the laser
level to create a straight line. Hmmm. Don't know if that will work. If it
does, though, I can then tape a ruler just below the straight line and
then mark of X's, which can then be center punched. This sounds like a lot
to go through, though. I'd rather just clamp a straight edge to the
aluminum, but how is that properly done?

In addition, I think I need to push the small bit way up into the chuck so
that its stiff. Yesterday when I was drilling holes, I watched the small
bit
I was using to drill pilot holes dance around on the metal. Another thing
I
did, which must have been stupid, is to put a drop of oil on the
centerpunched hole before I started drilling. That makes it hard to see
the
hole and line up the bit.


If the drill bit doesn't run true in the chuck, you are making life
difficult. The amount of stick-out doesn't really matter with small drills -
they are so flexible that they will bend anyway. What guides the drill bit
is the center punch mark. If you aim the drill bit at the mark as you bring
on (gently !) a little pressure, it will either settle into the mark or
skate around. If it skates around back off and try again - but do not apply
any pressure until it is running true. Depending on how hard you are holding
things down you can quite often 'feel' the drill centering in the punch
mark, at which point you may have to move the workpiece a little so that the
drill is truly aligned with the hole - applying pressure when the drill tip
is deflected is a good recipe for a broken drill !

As with all things, a little practise will soon give you the hang of things.

D




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In article 9Ik1d.263527$sh.202086@fed1read06, Daven Thrice says...

OK, I'm working with 1" extrusions, that are 90 deg. angles. I want to mark
a hole that is 1/4" in from one edge.

Use a scratch gage. Like I said, employ your dial calipers, or
if you want you can go to the hardware store and purchase a special
built one.

Jim


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"jim rozen" wrote in message
...
In article 9Ik1d.263527$sh.202086@fed1read06, Daven Thrice says...

OK, I'm working with 1" extrusions, that are 90 deg. angles. I want to
mark
a hole that is 1/4" in from one edge.

Use a scratch gage. Like I said, employ your dial calipers, or
if you want you can go to the hardware store and purchase a special
built one.

Ohhhh.... I get it. Open the calipers to 1/4", lock them in place, and drag
across the length of the piece. Don't need a straight edge for that. Then,
use the calipers like a compass to mark off one inch increments.

I've always built a lot of electronic stuff, but never really made things
out of wood or metal. Now, I've got a need to for some sheet metal stuff &
decided to take it on myself. For a little more than what I'd pay, probably,
to have somebody do this stuff for me, I've been able to pick up some tools
and stuff. So there's a bit of a learning curve. I don't know whether this
n.g. regularly gets questions as simple/dumb as mine, but I'm glad I found
this place.

In article XAn1d.264611$sh.258809@fed1read06,
Daven Thrice wrote:

"jim rozen" wrote in message
...
In article 9Ik1d.263527$sh.202086@fed1read06, Daven Thrice says...

OK, I'm working with 1" extrusions, that are 90 deg. angles. I want to
mark
a hole that is 1/4" in from one edge.

Use a scratch gage. Like I said, employ your dial calipers, or
if you want you can go to the hardware store and purchase a special
built one.

Ohhhh.... I get it. Open the calipers to 1/4", lock them in place, and drag
across the length of the piece. Don't need a straight edge for that. Then,
use the calipers like a compass to mark off one inch increments.

Close -- but if you do this, you will want two calipers. One
with two sharp points, and the other what is called a "hermaphrodite
caliper". That one has one leg bent 90 degrees to point in towards the
area between the two arms, while the other has an adjustable length
scribing arm. You rest the curved leg against the side of the reference
surface, and walk along dragging the point to make the mark. (FWIW, the
legs can be swiveled so the bend leg points out instead, and you can
mark off relative to an inside edge instead of an outside edge (such as
in the inside of your angle aluminum.

You should also consider getting some layout die -- the most
common is made by "Dykem". You have the choice of using blue or red. I
think that red works better with aluminum, but either can be used. This
makes the scribe lines show up clearly. You just brush it on with the
brush in the cap, and then wait a few minutes for it to dry.

An alternative to the hermaphrodite caliper is a standard
combination square -- set the blade to protrude 1/4" from the head, and
slide the head along your reference surface as you hold a sharp scriber
(usually stored in a hole in the head of the combination square) against
the end of the ruler and let its point scribe the workpiece.

Note that when drilling, some grades of aluminum can be rather
gummy, and will drill better if you use kerosene or WD-40 as a drilling
fluid.

Also -- it is easier to start a drill on center (even with a
center punch mark) if you have split point drills. They are far less
prone to "walk" away from where you try to start them. Your 1/4" bit
will otherwise have too large a 'chisel tip" (where the faces of the two
flats on the ends meet) and you will need to drill a pilot hole to match
the length of the chisel tip. (The split points also need less force to
drill cleanly -- not much of a problem with aluminum, but you will
notice it with steel.

I've always built a lot of electronic stuff, but never really made things
out of wood or metal.

Your dimensions sounded *almost* but not quite right for a pair
of relay rack rails and a relay rack panel -- except that the holes are
not all the same spacing. Instead, they alternate -- IIRC, one of one
spacing (between holes) and the next two another spacing, and then it
repeats.

A couple of other things to mention, since you are saying that
you are just getting started into metalworking:

1) Smaller things, and sheet metal must be constrained when
drilling -- the larger the hole, the more important. What
happens is just as the bit is about to break through the tip
grabs the sheet metal, and tries to both lift it from the table
and to spin it. A good drill press vise will help to hold
smaller things in place. For larger ones, make sure that one
end or the other is long enough to rest against the side of the
drill press column, to keep it from swinging around when the
drill bit catches. Failure to do this can result in you getting
some nasty cuts.

2) If your drill press is pristine, you have two choices:

a) Just go ahead and drill a hole somewhere in the table
so you won't feel quite so bad when a drill goes through
the workpiece and into the table.

b) Be careful to center the table so the drill bit will go
into the original hole in the center of the table, or
put some sacrificial material under the workpiece to
accept the tip of the drill as it breaks through. Wood
can work well for this.

For smaller workpieces, you will probably be holding
them in a drill press vise, and you can position it so
the drill bit passes beside the vise, and does not go
deep enough to touch the table. (For drilling the
angle, I would bolt the drill press vise to the drill
press table, and clamp it on the vertical side of the
angle, drill through, loosen the vise, slide the angle
aluminum along, re-clamp and drill the next. (You'll
probably want to reposition the vise for the last few
holes near one end.)

While you're about it -- also get a set of countersinks --
probably the best choice would be the kind which have a cone with a
pilot, and a hole drilled into one face of the cone to form a cutting
edge. This will chatter less than the other styles (which need a bit
more experience to minimize chatter), and use this on *both* sides of
the aluminum angle (and the aluminum panel) to remove the sharp burrs
left by the drilling.

It sounds as though you want to use screws to secure the plate
to the aluminum angle -- and if that is the case, I would suggest that
you drill the angle with a smaller hole -- the right size for a tap
drill for the thread you are using. I guess that you are aiming for
1/4-20, and IIRC, the tap drill for 1/4-20 is a #7 drill bit. Then tap
each hole (get a "gun" tap -- spiral point two flute designed to push
the chips ahead of the tap so you can just run the tap straight through.
You've got few enough holes so you can tap them by hand -- for a lot
more, I would suggest a tapping head (TapMatic is one maker, and the one
which I use.) Having the holes in the angle tapped means that you can
secure the plate to the angle with access to only one side, instead of
having to have the other hand behind the plate to hold a nut in place.

Now, I've got a need to for some sheet metal stuff &
decided to take it on myself. For a little more than what I'd pay, probably,
to have somebody do this stuff for me, I've been able to pick up some tools
and stuff. So there's a bit of a learning curve. I don't know whether this
n.g. regularly gets questions as simple/dumb as mine, but I'm glad I found
this place.

I hope that I haven't overdone it on suggestions -- but one
thing leads to another, and I think of how *I* would do the job (usually
with the tools on hand -- but I've been collecting them for many years. :-)

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 says...

Ohhhh.... I get it. Open the calipers to 1/4", lock them in place, and drag
across the length of the piece. Don't need a straight edge for that. Then,
use the calipers like a compass to mark off one inch increments.

Close -- but if you do this, you will want two calipers. One
with two sharp points, and the other what is called a "hermaphrodite
caliper".

Nope. I was saying to just use a regular set of dial (or electronic)
calipers. The jaw shapes are typically ground such that they
make excellent scratch gages. Of course you do tend to swarf up
the rack on some types, and it's a bit rough on the jaws.

You should also consider getting some layout die -- the most
common is made by "Dykem". You have the choice of using blue or red. I
think that red works better with aluminum, but either can be used. This
makes the scribe lines show up clearly. You just brush it on with the
brush in the cap, and then wait a few minutes for it to dry.

Almost anyone has an indellible sharpie pen in their kit. Works
just as well as dykem and can be pinpointed for the hole locations
so less cleanup is required.

Jim


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"Daven Thrice" wrote in message
news:mu81d.259560$sh.198210@fed1read06...
I have a piece of 1", 1/8" aluminum angle iron that is 18" long and 1/8"
thick. I want to drill sixteen holes in it, in a straight line, each hole
1"
away from the other. I also have a flat piece of aluminum that is 2" x 18"
x
1/8" thick. I want to drill two rows of 16 holes in that one. All holes
are
1/4" in diameter.

I've scrapped enough metal to set my ego aside and admit that I need help
with the very basics of basics. How do I make the measurements, mark them,
and then drill the holes?

Thanks!


If this is accurate enough it will be a lot easier for you...

http://home.tir.com/~artemus/Roy%20Doty/

In article XAn1d.264611$sh.258809@fed1read06, Daven Thrice says...

I've always built a lot of electronic stuff, but never really made things
out of wood or metal.

The 'calipers as scratch gage' is a pretty common technique for
chassis work in electronics. Most times it gives quite acceptable
results.

In that business, if you need parts to mate up then drill the
holes in assembly.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
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"Rick" wrote in message
nk.net...

"Daven Thrice" wrote in message
news:mu81d.259560$sh.198210@fed1read06...
I have a piece of 1", 1/8" aluminum angle iron that is 18" long and 1/8"
thick. I want to drill sixteen holes in it, in a straight line, each hole
1"
away from the other. I also have a flat piece of aluminum that is 2" x
18"
x
1/8" thick. I want to drill two rows of 16 holes in that one. All holes
are
1/4" in diameter.

I've scrapped enough metal to set my ego aside and admit that I need help
with the very basics of basics. How do I make the measurements, mark
them,
and then drill the holes?

Thanks!


If this is accurate enough it will be a lot easier for you...

http://home.tir.com/~artemus/Roy%20Doty/



Wow, Rick, thank you *very* much for taking the time to set that up and take
those pictures for me. That was a really nice thing to do. I'm not sure that
I can hang with that level of accuracy, but I'm going to poke around with it
because I have several rows of holes to drill. -- dt

For evenly spaced holes, get a good set of
dividers
and set the distance accurately. (I like to let the points "rest" in the
graduations of
the scale) Then step off the distance and use one leg of the divider to
scribe
across the first line, again pressing hard enough to make a good score which
you
can later feel. A little practice and it goes pretty quick.


While stepping off locations in that way is sometimes the easiest method, it's
not always the most accurate.

If your goal is to have the holes 1" apart, it's fine. But if your goal is to
have one hole at 1.5", the next at 2.5", etc., it's not so hot. If the
dividers are set slightly off, you'll get errors accummulating all in the same
direction. You'd be better off marking from a rule.

John Martin

JMartin957 wrote:

For evenly spaced holes, get a good set of
dividers
and set the distance accurately. (I like to let the points "rest" in the
graduations of
the scale) Then step off the distance and use one leg of the divider to
scribe
across the first line, again pressing hard enough to make a good score which
you
can later feel. A little practice and it goes pretty quick.


While stepping off locations in that way is sometimes the easiest method, it's
not always the most accurate.

If your goal is to have the holes 1" apart, it's fine. But if your goal is to
have one hole at 1.5", the next at 2.5", etc., it's not so hot. If the
dividers are set slightly off, you'll get errors accummulating all in the same
direction. You'd be better off marking from a rule.

John Martin

One fast way to check for gross errors with the step off method is to step off
around the circle in the opposite direction and see how close you come to the
original marks.

Close enough for sheet metal.

--RC