Homebrew PCBs

On Mon, 28 Nov 2005 18:14:00 +0100, Dave <wa4qal@...> wrote:

> 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


That doesn't really change that jacobs chucks have awful runout, esp. the  
cheaper ones (but then, dremel collets are probably no better).
I don't say there are no precision jacobs chucks, just that most aren't  
precision.

Most carbide drills come with the same size shank, so i never changed the  
collet, and for HSS the runout of a jacobs chuck doesn't matter anyway.  
There are a few carbide drills out there with the shank same dia. as the  
business end, but i simply avoid them.

ST