Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Here are some drilling machine ideas.

I have a small high speed drill press that works great with carbide
drill bits. For simple low volume jobs this drill press can't be
beat. I think it works much better than the Dremel tool types. This
drill press was on sale recently at KBC Tools for $130.

For the more complex jobs I like to use a stylus operated drilling
system. The machine I use is made by Nawide Machine Tools. It has an
optical scope for making the master template or for drilling smaller
quantities. The scope screen has 15 power magnification and a
clamping system. You line up the pad in the optical screen and push
the foot switch. The machine pressure foot clamps the stack of boards
or template, drills the hole from a bottom mounted spindle, retracts
the drill bit and releases the pressure foot. It is very quick and
every bit as accurate as the best CNC machine. If you make a template
and attach the stylus assembly you can drill 60-80 holes per minute
with precise placement. We usually stack the panels three deep and
sometimes four deep depending on the smallest drill size when using
this machine.

Here is the best part. These machines can be purchased for next to
nothing. The last machine I bought was only $200 and had the optical
scope and stylus assembly. It is a 1986 vintage Aetna Acrodrill in
perfect condition. The commercial shops have very little use for
these machines and will almost give them away. Another machine to
look for is any of the Excellon Quad Drills. These machines had a
stylus assembly on a very smooth manual XY movement with four high
speed spindles. This machine can be made into a CNC version by just
adding the XY leadscrews and computer. These nmachines are smaller
than an office desk and have built in casters for easy moving.

Excellon even made a version of this called a Quadramatic 1255 and
Quadramatic 1231. The 1255 accepted 12" x 18" panels and the 1231
took 10" x 12" panels. The XY movement is driven by ball screws. I
can assure all of you that these machines are excellent for hobby AND
professional drilling. Take off the old General Electric NC control
system and interface with your own PC CNC control system. Very
little mechanical work would be needed and you would really have
something to show off. I have personally turned down offers to haul
these away for free. They are not that big or heavy and will fit in
any pickup truck. Most of these systems have already hit the dump or
scrap yard but if you can find one you will not be sorry.

I have owned very large and expensive Excellon drilling and routing
machines in the past and the only thing they had over the methods
discussed above was speed and expense. My favorite drill was the
Excellon EX-200 Driller/Router with CNC-6 controller but even this
expensive machine was only averaging about 125 holes per minute. I
can drill the ten boards I need each week in less than 20 minutes
with a stylus drill. This includes setup time on a 4" x 6" board with
300 holes.

Save some money and try out some of these ideas. You will be amazed
with the results.

Tom