On Tue, 7 Jul 2015 13:46:09 +0000 (UTC), you wrote:
>Here is a few tips to get good centering of vias & through holes.
>1) Copy and paste your final PCB layout to the desktop & rename "xxx Shrink",(where xxx is your own board name)2) Open your renamed copy & reduce all of the hole sizes to 0mm5 (0.5mm). Save and close.3) Use the renamed copy as your master, Print & expose in whatever method you using(U.V. Toner Transfer etc)
>4) Etch, clean & electroless plate(if used)5) Use a spring loaded center-punch(google Automatic center-punch) on its lowest possible setting to "dimple" each hole & finally drill with a 0mm8(0.8mm) drill bit. Take your time with this step to achive precise holes!
>6) Enlarge any other holes to their required diameters
>
>Using this method takes longer but stops "run out" ,wandering & fewer bits snapping....AND gives you a near perfectly centered hole when using a Dremmel Drill & StandI hope this helps with tha alaignment problem on S/S double & D/S BoardsChester
Dremel has a very bad chuck and bearings for PC board drilling. If
the stand has any kind of wobble in it, that will also have an effect.
If you have access to a Proxxon rotary tool, it has a 4 jaw chuck
rather than three, and is made of steel rather than aluminum.
I've found it to be better in performance, and I've tried both.
However, if the drill press mechanism wobbles from side to side, that
must also be fixed.
Harvey