Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "Mike Young" <mikewhy@s...> wrote:
>
> The concentricity of the bearings on the chuck, and the chuck's
ability to 
> center the bit accurately, are in question. I have to agree with
Evan that 
> these are important considerations. Rotary tools with collets -- e.g.: 
> Dremels, Rotozips, routers, laminate trimmers -- will have less
run-out than 
> a Jacobs chuck. Also, the higher speed is useful for making very small 
> holes.

One of the problem with a collet mount is that it only accepts 
certain sizes of bits.  Fortunately, Dremel has a Jacobs style 
chuck that will attach to the business end of a Dremel tool and 
allow precision mounting of very tiny bits.  It's item 4486, near 
the bottom of this page:

http://www.dremel.com/HTML/products/accessories/accessories.pdf

Dave

> All is not lost. The most important attribute is that it can guide a
tool, 
> held somewhat rigidly, in a direction more or less perpendicular to
the work 
> table. Certainly it's possible to drill a PCB even by hand (with some 
> gnashing and great peril to the bits); guiding one with press is
already a 
> great improvement. If you can find a cheap Dremel, and some way to
mount it 
> to the press, it would be close to an ideal drilling station. Bronze 
> grounding clamps found in the electrical department of Home Depot
etc. are 
> almost custom made for holding their round-ish shapes.
> 
> [BTW: did anyone else catch the recent revival of the Rotozip? :)
For future 
> reference, five years is about the right interval for re-introducing
retail 
> flops. It lacked a usable base in its original incarnation. Adding
one drove 
> its price up to where a real laminate trimmer is a viable
alternative. I 
> suggest waiting a few months, and see if you can find something on
overstock 
> for $30 or so. Its 30k rpm motor and huge cooling fan are what you're 
> after.]