A fair bit back, Jim Rozen described a drill press for Printed Circuit
Boards that sounded like a good design. A microscope with a cross hair
to align the board, and a drill that comes up from the other side to
drill the hole.

So the first step was to figure out what to use for a spindle for the
drill press and how to drive it. My choice was a small trim router
that HF sells as low as $20. The second thing was to make a new collet
to hold carbide PCB drills.
Measured the angle of the existing collet as 30 degrees ( 15 degrees on
the lathe compound ). But how to get an accurate hole with very little
run out.

Well the first problem was to get an accurate diameter hole. A 1/8
inch bit makes a hole that is too large. And the next size down was too
small. So googled on this group for ideas and tried to make a small
boring bar out of a broken drill. The drill was about a 3/16 drill and
I never did manage to make a decent boring bar.

Okay a D drill will do it and I had several broken PCB drills. And
fortunately a small ( about 4 inch )diamond wheel. Much better luck
than I had trying to make a boring bar. Got one collet drilled out,
but had guessed at the outside diameter. Bad idea. Made another
collet and nearly got it right. I left a little straight bit at the
small end of the taper that was just a little too big in diameter. So
pushed a broken PCB drill in and then chucked it in the drill press and
filed that to fit. Also smoothed up the tapered part with the file.
It seemed to be true before I did that, but it couldn't hurt.

So now I more or less have a collet. I will have to buy a slitting saw
to put a slit in it, but the hole is tight enough to hold a PCB drill
now. Can't see any run out. I think that part will work.

Dan

wrote:

A fair bit back, Jim Rozen described a drill press for Printed Circuit
Boards that sounded like a good design. A microscope with a cross hair
to align the board, and a drill that comes up from the other side to
drill the hole.

Dust? Drilling PCBs makes lots of abrasive dust that will get into your
bottom motor spindle bearings. If the board is already etched, you don't
need a microscope or cross hairs to align the drill bit in the center of
the pads. The lack of copper in the middle of the pad will center the
bit automatically if the operator can get it reasonably close. And if
you need better accuracy than that, then CNC is the way to go (it
doesn't need the microscope or cross hairs either).

[...]

So now I more or less have a collet. I will have to buy a slitting saw
to put a slit in it, but the hole is tight enough to hold a PCB drill
now. Can't see any run out. I think that part will work.

Dan


Aren't there 1/8" collets in most Dremel-type motors? Making a collet
from scratch sounds like reinventing the wheel. Carbide PCB drills #60
and below like to run at 25K RPM -- your home brew collet had better be
pretty accurate in run out if you expect the bits to last longer than
about three holes.

"Tim Killian" wrote in message
...


wrote:

A fair bit back, Jim Rozen described a drill press for Printed Circuit
Boards that sounded like a good design. A microscope with a cross hair
to align the board, and a drill that comes up from the other side to
drill the hole.

Dust? Drilling PCBs makes lots of abrasive dust that will get into your
bottom motor spindle bearings. If the board is already etched, you don't
need a microscope or cross hairs to align the drill bit in the center of
the pads. The lack of copper in the middle of the pad will center the bit
automatically if the operator can get it reasonably close. And if you need
better accuracy than that, then CNC is the way to go (it doesn't need the
microscope or cross hairs either).

The old Excellon PCB drilling machines used a similar arrangement. They had
a projection microscope that displayed the pads on a ground glass screen,
with cross hairs. I'd be inclined to use a web cam for viewing the pad.

Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller

In article . com,
says...

A fair bit back, Jim Rozen described a drill press for Printed Circuit
Boards that sounded like a good design. A microscope with a cross hair
to align the board, and a drill that comes up from the other side to
drill the hole.

Good memory. I had run that thing at the university of arizona
at tucson, in 1978. I honestly cannot remember if it was a
commercial unit, or was home-made by the shop's boss. He was
that kind of guy so it may have been home-made.

The spindle and motor were out of a Dumore drill press, I remember
that. They were rigged to rise up from below under the action
of an air piston, tripped by an electric foot switch. I seem to
recall that the drill was held in a chuck, maybe the tiny albrecht
one, on the motor spindle. A collet of course would be less expensive.

It was pretty filthy work, I think there was a vacuum rigged up to
pull the swarf out of the working area. If I were doing that today
I would vent it outside, G-10 is not the best stuff to be working
with.

This was nearly before the days of NC pcb machines, and for protoypting
work it was pretty nice. They also did their own multi-level boards
via tape on acetate, which were then optically reduced. Then they
had their own expose, develop, and etch setup as well.

These days board houses are numerous, good, and inexpensive - if
you are doing even a few, you might consider just shipping them a
gerber file.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

Tim Killian wrote:


wrote:

A fair bit back, Jim Rozen described a drill press for Printed Circuit
Boards that sounded like a good design. A microscope with a cross hair
to align the board, and a drill that comes up from the other side to
drill the hole.

Dust? Drilling PCBs makes lots of abrasive dust that will get into your
bottom motor spindle bearings.

Make a thin rubber disk, pierce the center, and slip it over the drill
so it covers the collet and bearings below. Make it small and very round
so it won't come apart at high RPM.
Might have to use a plastic disk

Not so much a good memory, as using Google to look for threads on
drilling PCB's. I do try to read all of your on topic posts and some
of the OT ones as well. Always interesting.

I will have to figure out some way to capture the swarf. I don't want
something as noisy as a shop vacuum running but will have to rig
something.

This is just for prototypes. If I get something that I want to make
very many I will farm it out.

Dan
jim rozen wrote:


Good memory. I had run that thing at the university of arizona
at tucson, in 1978. I honestly cannot remember if it was a
commercial unit, or was home-made by the shop's boss. He was
that kind of guy so it may have been home-made.


It was pretty filthy work, I think there was a vacuum rigged up to
pull the swarf out of the working area. If I were doing that today
I would vent it outside, G-10 is not the best stuff to be working
with.


These days board houses are numerous, good, and inexpensive - if
you are doing even a few, you might consider just shipping them a
gerber file.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

Good idea. I have a web cam that I can use. Maybe just draw a cross
hair on the screen with a sharp wax pencil when I use it.


Dan

Seems like changing out a broken bit would be a PITA if it's located
under a stage or table. For manual drilling, I just don't see the big
advantage of the "bottom up" method over a standard precision drill
press with an illuminated magnifier attached. Another advantage of a
regular drill press is that it can be used for other types of drilling,
not just PCBs.

Leon Heller wrote:

"Tim Killian" wrote in message
...


wrote:


A fair bit back, Jim Rozen described a drill press for Printed Circuit
Boards that sounded like a good design. A microscope with a cross hair
to align the board, and a drill that comes up from the other side to
drill the hole.


Dust? Drilling PCBs makes lots of abrasive dust that will get into your
bottom motor spindle bearings. If the board is already etched, you don't
need a microscope or cross hairs to align the drill bit in the center of
the pads. The lack of copper in the middle of the pad will center the bit
automatically if the operator can get it reasonably close. And if you need
better accuracy than that, then CNC is the way to go (it doesn't need the
microscope or cross hairs either).


The old Excellon PCB drilling machines used a similar arrangement. They had
a projection microscope that displayed the pads on a ground glass screen,
with cross hairs. I'd be inclined to use a web cam for viewing the pad.

Leon

What you describe is a miniature centrifugal blower wheel located right
at the point where the dust is created. At 25K RPM, it will do an
excellent job of spreading fiberglass dust over a wide area ;-)

Rex B wrote:

Tim Killian wrote:



wrote:

A fair bit back, Jim Rozen described a drill press for Printed Circuit
Boards that sounded like a good design. A microscope with a cross hair
to align the board, and a drill that comes up from the other side to
drill the hole.

Dust? Drilling PCBs makes lots of abrasive dust that will get into
your bottom motor spindle bearings.


Make a thin rubber disk, pierce the center, and slip it over the drill
so it covers the collet and bearings below. Make it small and very round
so it won't come apart at high RPM.
Might have to use a plastic disk

I am still thinking about the dust problem. My thoughts now are to use
a smallish squirrel cage fan and suck the dust into a pleated paper
filter. And build a box around the motor and blow air into the box.
Maybe a blower with two squirrel cage blowers or maybe the filtered
air would be clean enough to use to cool and keep the motor clean.

I think my collet is accurate enough, but the proof will be if I can
drill a # 80 hole. Making a collet from scratch is not cost effective.
If I counted my time as worth anything, it would have been cheaper to
buy a Dremel tool. But I did learn from the experience.


Dan

I am thinking of doing something like that.

I already have a regular drill press, but not one suitable for PCB's.
The router motor has a lot more RPM's and less run out. I hope to make
something suitable for a lot less than a small high speed drill press
would cost. Hell I hope to spend less than a 0-1/4 precision drill
chuck costs. Changing bits will be more of a pain, but I hope not
too bad. The router motor will be held in a clamp so it can be easily
removed to change bits.


Dan

I don't know what your budget is, but for $200 you can buy a very
capable hobby machine with multiple uses:

http://www.ares-server.com/Ares/Ares...oduct&ID=82959

The top speed is a bit low for drilling PCBs.

wrote:

I already have a regular drill press, but not one suitable for PCB's.
The router motor has a lot more RPM's and less run out. I hope to make
something suitable for a lot less than a small high speed drill press
would cost. Hell I hope to spend less than a 0-1/4 precision drill
chuck costs. Changing bits will be more of a pain, but I hope not
too bad. The router motor will be held in a clamp so it can be easily
removed to change bits.


Dan

In article , Tim Killian says...

Seems like changing out a broken bit would be a PITA if it's located
under a stage or table. For manual drilling, I just don't see the big
advantage of the "bottom up" method over a standard precision drill
press with an illuminated magnifier attached.

Parallax error. The planar view of the trace on the board
was a big help. The drill was swapped easiy from under
the table.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

wrote:

A fair bit back, Jim Rozen described a drill press for Printed Circuit
Boards that sounded like a good design. A microscope with a cross hair
to align the board, and a drill that comes up from the other side to
drill the hole.


Here's what I do. http://pico-systems.com/wwspndl.html

Of course, I was incredibly lucky to get these Westwind air bearing
spindles.
The guy who sold them to me had no idea that bad units carried a $6000
core charge with the rebuilders! (Maybe a rebuild is $6000 with return
of the
core, I'm not sure anymore.)

I made a bracket to clamp it to the spindle of my Bridgeport. I have
successfuly
drilled boards with .018" drills. I can't drill a stack of two boards
at that size,
however. This blind drilling allows me to use backup material and entry
material,
so I get minimum ridges around the holes. I use blank (no copper) PCB
material
as the back-up, and .010" aluminum roof flashing as the entry material.
I align
pre-etched boards without the entry material first, then insert the
entry material
under the clamps on one side first, then the other, so that the board
can't move.

I also pre-drill the blank boards, then laminate the resist and expose
and etch.
That way I don't have to fool around with the aligning on the mill.
But, I can't
have pre-laminated board blanks at the ready, either.

I make master artwork for exposing the resist with my laser photoplotter
http://pico-systems.com/photoplot.html (Ugh, GOT to make new photos
of this project!)

Before all this automation, I had a hand-steered drill with a pedal to
stroke the
bit. It worked pretty well, too. Really no need for a microscope.

Jon

wrote:

I am still thinking about the dust problem. My thoughts now are to use
a smallish squirrel cage fan and suck the dust into a pleated paper
filter. And build a box around the motor and blow air into the box.
Maybe a blower with two squirrel cage blowers or maybe the filtered
air would be clean enough to use to cool and keep the motor clean.

I think my collet is accurate enough, but the proof will be if I can
drill a # 80 hole. Making a collet from scratch is not cost effective.
If I counted my time as worth anything, it would have been cheaper to
buy a Dremel tool. But I did learn from the experience.


I seriously doubt it! An Excellon drill has a 7 ton granite base, air
bearing
sliders on the X and Y axes, the spindles are mounted to another granite
beam.
The spindles use air bearings, and hold runout to under 0.0001". They
can drill
..012" holes pretty well at 80,000 RPM, but that is about the limit. These
machines go for $200,000 and up. I was pretty amazed I could drill .018"
(about #77) holes with my lash-up of a Westwind spindle on a Bridgeport.
Using a standard VFD, I can only do 24,000 RPM (400 Hz), which is way
too low
for a drill that small. But, that is small enough for anything I'll
ever do. Just
the right size to poke a wire wrap wire through for a via.


Jon

jim rozen wrote:

I had run that thing at the university of arizona
at tucson, in 1978. snip
This was nearly before the days of NC pcb machines, and for protoypting
work it was pretty nice.

No, actually the spindles and axis drives I have were RETIRED before 1978.
It was a complete CNC PCB drill by Excellon. It used a GE Mark Century
control, all discrete germanium transistors on single-sided paper-phenolic
circuit boards. GHASTLY nightmare, I didn't even want to LOOK at the
horrible control! (Not CRT CNC, not even CNC, but tape NC, just enough
smarts to position to the X Y coords and stroke the drill.)

Jon

Tim Killian wrote:
What you describe is a miniature centrifugal blower wheel located right
at the point where the dust is created. At 25K RPM, it will do an
excellent job of spreading fiberglass dust over a wide area ;-)

And the problem is...?

Jon Elson wrote:


jim rozen wrote:

I had run that thing at the university of arizona
at tucson, in 1978. snip
This was nearly before the days of NC pcb machines, and for protoypting
work it was pretty nice.

No, actually the spindles and axis drives I have were RETIRED before 1978.
It was a complete CNC PCB drill by Excellon. It used a GE Mark Century
control, all discrete germanium transistors on single-sided paper-phenolic
circuit boards. GHASTLY nightmare, I didn't even want to LOOK at the
horrible control! (Not CRT CNC, not even CNC, but tape NC, just enough
smarts to position to the X Y coords and stroke the drill.)

So it's the thing that takes the "drill tape"
file from my PCB CAD program.

Was that called a Uni Drill and then they had a Quad....thats going back a
bit.


"Leon Heller" wrote in message
...
"Tim Killian" wrote in message
...


wrote:

A fair bit back, Jim Rozen described a drill press for Printed Circuit
Boards that sounded like a good design. A microscope with a cross hair
to align the board, and a drill that comes up from the other side to
drill the hole.

Dust? Drilling PCBs makes lots of abrasive dust that will get into your
bottom motor spindle bearings. If the board is already etched, you don't
need a microscope or cross hairs to align the drill bit in the center of
the pads. The lack of copper in the middle of the pad will center the bit
automatically if the operator can get it reasonably close. And if you
need better accuracy than that, then CNC is the way to go (it doesn't
need the microscope or cross hairs either).

The old Excellon PCB drilling machines used a similar arrangement. They
had a projection microscope that displayed the pads on a ground glass
screen, with cross hairs. I'd be inclined to use a web cam for viewing the
pad.

Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller

In article , Jon Elson says...



jim rozen wrote:

I had run that thing at the university of arizona
at tucson, in 1978. snip
This was nearly before the days of NC pcb machines, and for protoypting
work it was pretty nice.

No, actually the spindles and axis drives I have were RETIRED before 1978.

Pardon me, Jon. That was before *UA* had an NC pcb drilling
machine! :^)

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

Jim Stewart wrote:
Jon Elson wrote:



jim rozen wrote:

I had run that thing at the university of arizona
at tucson, in 1978. snip
This was nearly before the days of NC pcb machines, and for protoypting
work it was pretty nice.

No, actually the spindles and axis drives I have were RETIRED before
1978.
It was a complete CNC PCB drill by Excellon. It used a GE Mark Century
control, all discrete germanium transistors on single-sided
paper-phenolic
circuit boards. GHASTLY nightmare, I didn't even want to LOOK at the
horrible control! (Not CRT CNC, not even CNC, but tape NC, just enough
smarts to position to the X Y coords and stroke the drill.)


So it's the thing that takes the "drill tape"
file from my PCB CAD program.

Yup, that's right. What a horror. I was glad to leave all that to the
guy who was going to scrap the rest, with the 7 tons of granite!

Jon