Homebrew PCBs

Having seen an old manual Excellon PCB drilling machine in action recently,
I got to thinking about an up-to-date version suitable for home
construction.

The nice thing about the Excellon was the large screen showing the magnified
pad with cross- hairs, so that the drill could be exactly centred on the
pad. One way to achieve this might be to use a webcam with a suitable lens
attached underneath the PCB, with some software to create the cross-hairs.
Alignment of the system could be achieved by lowering the drill with a bit
in it, so that it was in focus, and moving the webcam/lens in the X and Y
planes until the tip of the drill was centred. Centering a pad, then
operating the drill, should result in the hole being exactly in the pad
centre.

It might be easier mechanically  to mount the camera horizontally, and use a
45 degree mirror beneath the drill table.

I might try this with the rather crummy Microcraft drill and stand I use.
Refinements like an automatic clamp for the PCB, and automatic drill feed,
could be added, of course.

Any comments?

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

I have been looking into creating crosshairs on my regular drill press with a 
pair of low-cost ($5) laser pointers, each setup to project a thin straight 
line.  By using 2, it would eliminate any error due to varying board 
thicknesses.  Still need to find a laser pointer that can project a thin line 
though.  Most of the ones I have seen will do points, stars, hearts, etc.

BTW, I was in Harbor Freight (here in the U.S.) a few days ago, and they have 
the 8" drill press on sale again for an awesome price of $40.  This is a 
proper "full-size" drill press, and I much prefer this over a wobbly dremel 
or hobby-type drill.  No, it's definitely not as fast, but is excellent for 
drilling PCB's, costs less, and is much quieter.

Cheers,
-Neil.



On Wednesday 09 July 2003 05:19, Leon Heller scribbled:

> Having seen an old manual Excellon PCB drilling machine in action recently,
> I got to thinking about an up-to-date version suitable for home
> construction.
>
> The nice thing about the Excellon was the large screen showing the
> magnified pad with cross- hairs, so that the drill could be exactly centred
> on the pad. One way to achieve this might be to use a webcam with a
> suitable lens attached underneath the PCB, with some software to create the
> cross-hairs. Alignment of the system could be achieved by lowering the
> drill with a bit in it, so that it was in focus, and moving the webcam/lens
> in the X and Y planes until the tip of the drill was centred. Centering a
> pad, then operating the drill, should result in the hole being exactly in
> the pad centre.
>
> It might be easier mechanically  to mount the camera horizontally, and use
> a 45 degree mirror beneath the drill table.
>
> I might try this with the rather crummy Microcraft drill and stand I use.
> Refinements like an automatic clamp for the PCB, and automatic drill feed,
> could be added, of course.
>
> Any comments?
>
> Leon

----- Original Message ----- 

  From: Neil 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Wednesday, July 09, 2003 1:16 PM
  Subject: Re: SPAM: [Homebrew_PCBs] Drilling machine idea


  I have been looking into creating crosshairs on my regular drill press with a 
  pair of low-cost ($5) laser pointers, each setup to project a thin straight 
  line.  By using 2, it would eliminate any error due to varying board 
  thicknesses.  Still need to find a laser pointer that can project a thin line 
  though.  Most of the ones I have seen will do points, stars, hearts, etc.

  BTW, I was in Harbor Freight (here in the U.S.) a few days ago, and they have 
  the 8" drill press on sale again for an awesome price of $40.  This is a 
  proper "full-size" drill press, and I much prefer this over a wobbly dremel 
  or hobby-type drill.  No, it's definitely not as fast, but is excellent for 
  drilling PCB's, costs less, and is much quieter.

  Cheers,
  -Neil.

  Make sure the quill is ok. Some of the HF presses I've seen have had 0.020 slop in the quill. Then again, they were not brand new, but had been used for drilling metal etc. We had one at the airport, and a friend had another one at home. Both were too sloppy for even a 1/16" drill bit, but worked fine for 1/4" holes etc, and worked well for wood. This was a couple years back, and I realize HF changes suppliers fairly often, so the new ones may be much better. I buy a lot of stuff from them, the carbide pcb drills have been great, as have a lot of other items, I'm just a little paranoid about the low cost drill press. At $40 its 1/2 the price of a dremel!!!

  Thanks
  Ron

[Non-text portions of this message have been removed]

Leon Heller wrote:
> Having seen an old manual Excellon PCB drilling machine in action recently,
> I got to thinking about an up-to-date version suitable for home
> construction.
> 
> The nice thing about the Excellon was the large screen showing the magnified
> pad with cross- hairs, so that the drill could be exactly centred on the
> pad. One way to achieve this might be to use a webcam with a suitable lens
> attached underneath the PCB, with some software to create the cross-hairs.
> Alignment of the system could be achieved by lowering the drill with a bit
> in it, so that it was in focus, and moving the webcam/lens in the X and Y
> planes until the tip of the drill was centred. Centering a pad, then
> operating the drill, should result in the hole being exactly in the pad
> centre.

 From what Tom was once explaining about the manual Excellon PCB 
drilling machines he suggested the video camera is the way to go 
for this. I priced some of those cheapy B&W CCD camera modules 
and they retail for about AUD$60. They connect directly to any 
old TV/monitor with a composite video input. I can't see any 
optical cross hair eyepiece system being any cheaper or easier 
that a video display.

How were the cross hairs made visible ? Was it just some lines 
drawn on the glass of the monitor ?
Alignment should be easy. Just drill a hole , and while keeping 
the PCB in the same position you adjust the camera angle so the 
hole aligns up with the cross hairs ?

This is something what I might be able to add to my drill press.
http://home.alphalink.com.au/~seychell/drill_MkII.html

>  From what Tom was once explaining about the manual Excellon PCB 
> drilling machines he suggested the video camera is the way to go 
> for this. I priced some of those cheapy B&W CCD camera modules 
> and they retail for about AUD$60. They connect directly to any 

The problem with a camera below the print is that it will be blind 
after a few drills. Well maybe one could use a piece of glass to 
shield it and a air pump to keep the surface clean.

Some people actually reverse their drill, so the drill comes up 
through the PCB. That way, the lens of the camera can point down.
It also needs a special strong directional light arrangement.

Still, for very fine work, the essential problem is that good drills 
in 0.5-0.8mm are expensive and break just too easily.

- Carsten

>   Make sure the quill is ok. Some of the HF presses I've seen have 
had 0.020 slop in the quill. Then again, they were not brand new, but 
had been used for drilling metal etc. We had one at the airport, and 
a friend had another one at home. Both were too sloppy for even a 
1/16" drill bit, but worked fine for 1/4" holes etc, and worked well 
for wood. This was a couple years back, and I realize HF changes 
suppliers fairly often, so the new ones may be much better. I buy a 
lot of stuff from them, the carbide pcb drills have been great, as 
have a lot of other items, I'm just a little paranoid about the low 
cost drill press. At $40 its 1/2 the price of a dremel!!!

Good point.  the quill is very sloppy on the HF press, but there is a 
way to increase that accuracy to super presision levels.

mount a shaft on the drill press column and then on that shaft, mount 
a bearing to hold a shaft, and on that shaft mount your tiny drill 
chuck.

the HF press would be the Z axis, and the runout or slop would be 
eleminated by the adapter.  This is how a Jig Bore machine is made 
and those are super accurate.

Also, a magnifying glass mounted on the machine would offer much of 
the visual stuff needed to line up holes.

Dave

Do you have a link to a drawing? This sounds very interesting. I'm not quite following the process, and a picture might help. I did a google search, and can't seem to envision how such an adaptor works, as all I found were milling style machines...

Thanks
Ron

  ----- Original Message ----- 
  From: Dave Mucha 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Friday, July 11, 2003 11:51 AM
  Subject: [Homebrew_PCBs] Drilling machine idea HF drill press


  >   Make sure the quill is ok. Some of the HF presses I've seen have 
  had 0.020 slop in the quill. Then again, they were not brand new, but 
  had been used for drilling metal etc. We had one at the airport, and 
  a friend had another one at home. Both were too sloppy for even a 
  1/16" drill bit, but worked fine for 1/4" holes etc, and worked well 
  for wood. This was a couple years back, and I realize HF changes 
  suppliers fairly often, so the new ones may be much better. I buy a 
  lot of stuff from them, the carbide pcb drills have been great, as 
  have a lot of other items, I'm just a little paranoid about the low 
  cost drill press. At $40 its 1/2 the price of a dremel!!!

  Good point.  the quill is very sloppy on the HF press, but there is a 
  way to increase that accuracy to super presision levels.

  mount a shaft on the drill press column and then on that shaft, mount 
  a bearing to hold a shaft, and on that shaft mount your tiny drill 
  chuck.

  the HF press would be the Z axis, and the runout or slop would be 
  eleminated by the adapter.  This is how a Jig Bore machine is made 
  and those are super accurate.

  Also, a magnifying glass mounted on the machine would offer much of 
  the visual stuff needed to line up holes.

  Dave




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[Non-text portions of this message have been removed]

sonds much like the HF press is only a "heavy stand" then?
if you have to add the bearing shafts etc...
i think you could attach a lever for operating it and get rid of the 
original press?

i am sure i am wrong but i only want you to figure this out more detailed 
;-) .


if anyone wants to see some drill press samples look here:
http://www.megauk.com/cgi- 
bin/mega/lp.pl?page=http://www.megauk.com/pcb_drilling_machines.php


i also think that it is not a good idea to use a full size drill press 
(without that "use youe own spindle on some rail" method).
because it is far too slow.
i think 10000 to 20000 rpm is minimum...

regards
st

--- In Homebrew_PCBs@yahoogroups.com, "Ron Amundson" 
<ron_amundson@h...> wrote:
> Do you have a link to a drawing? This sounds very interesting. I'm 
not quite following the process, and a picture might help. I did a 
google search, and can't seem to envision how such an adaptor works, 
as all I found were milling style machines...
> 
> Thanks
> Ron


very simple scketch in the photos section.

this mod can be done by anyone with hand tools.  the key is only to 
line up the shaft.

a flange bearing can be had for about $10.00 an will self align and 
is hardened.  that means that all one has to do is bolt it aligned as 
well as possible under the axis of the drill column.

If one were to make the column collar with an angle as shown, then 
the top plate can be removed for other work.

Dave

Ahaa, great idea. Do you get any vibration from the loose tolerance drill chuck? I'm thinking it self aligns to the flange bearing so you don't, but not sure. I will need to build one of these.

Thanks 
Ron

  ----- Original Message ----- 
  From: Dave Mucha 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Friday, July 11, 2003 5:21 PM
  Subject: [Homebrew_PCBs] Re: Drilling machine idea HF drill press


  --- In Homebrew_PCBs@yahoogroups.com, "Ron Amundson" 
  <ron_amundson@h...> wrote:
  > Do you have a link to a drawing? This sounds very interesting. I'm 
  not quite following the process, and a picture might help. I did a 
  google search, and can't seem to envision how such an adaptor works, 
  as all I found were milling style machines...
  > 
  > Thanks
  > Ron


  very simple scketch in the photos section.

  this mod can be done by anyone with hand tools.  the key is only to 
  line up the shaft.

  a flange bearing can be had for about $10.00 an will self align and 
  is hardened.  that means that all one has to do is bolt it aligned as 
  well as possible under the axis of the drill column.

  If one were to make the column collar with an angle as shown, then 
  the top plate can be removed for other work.

  Dave




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[Non-text portions of this message have been removed]

--- In Homebrew_PCBs@yahoogroups.com, "Ron Amundson" 
<ron_amundson@h...> wrote:
> Ahaa, great idea. Do you get any vibration from the loose tolerance 
drill chuck? I'm thinking it self aligns to the flange bearing so you 
don't, but not sure. I will need to build one of these.
> 
> Thanks 
> Ron


The nice thing is that if you make the collar on a lathe or mill, 
with close tollerances you can mill on the drill press too.

one problem there is that side to side can only take a little 
pressure but into the column, you can get a better cut.

verticle control is poor at best, but if it is the only thing you 
got.....