Homebrew PCBs

In a message dated 18-Apr-02 11:00:31 Central Daylight Time, 
marble_h@yahoo.com writes:


> 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:  In MY opinion, even 1/16" is much too big for MOST things, other than, 
maybe, the leads of some TO-220 and TO-208 devices, or 2 W. (U.S. made!) 
resistors, etc.  

For "most leaded devices in the DIP-IC and ¼ W. R. range", #56 is small 
enough that the gap between the lead and the pad - the space "flying solder" 
must span - is acceptable, yet large enough to accept on up to, say, ½ W. R's 
and "big capacitor leads", etc.  

For some "tiny stuff" I have gone as small as #72, but this is really rare 
and difficult.  #60 ought to be as small as any hobbiest should ever have to 
go.  Remember:  It is vastly easier to RE-DRILL with a larger bit than to 
UN-DRILL with a smaller one!

Jan Rowland


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