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.]