--- 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.pdfDave
> 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.]