Homebrew PCBs

Hi,
   I answered this one but it got lost in Yahoo. The DXF file
causes the Milling Bit to put a tiny dot in each pad. The dot
is only as deep as you mill. This dot is then drilled out with
a number 60 bit. I use a No. 60 because it lets me put all my
parts in with one size hole.
    When you etch with acid you can put a tiny circle in each pad
of your drawing. This puts in a starter hole during etching. The
hole is only through the copper.
     If you mill using a drill bit make sure it is CARBIDE! HSS
will not mill for long. PCB material is like sandpaper to a bit.


                                        John  



--- In Homebrew_PCBs@y..., "marble_h" <marble_h@y...> wrote:
> What is the most common size dill bit used in PCB work ?
> 
> John I noticed that in your G-code that you used the same size bit 
> for both millimg and drilling  what size was it .I was thinking of 
> useing a 1/16 bit but the machine I can use has a 3/32 as the 
> smallest right now . I think that is way to big .I was thinking of 
> useing a #55 dill size for the paths ( 1/16 is bigger I know ) and 
> #60 for the mount points these may be to small any thoughts (John)
> (Group)
> 
> What is the best to use   By the way I am makeing the 3amp driver 
> from Steve Blackmore on his site . I have almost completed the 
files 
> meeded to make the G-code . Now I know why G-code is so protected 
if 
> you make one up .
> 
> John Brauweiler