[sdiy] PCB drill size tolerance

John Luciani jluciani at gmail.com
Sat Nov 8 16:32:04 CET 2008

On Sat, Nov 8, 2008 at 8:41 AM, Justin Owen <juzowen at googlemail.com> wrote:
> Hello,
> I'm laying out a simple, one-sided PCB to be produced by a commercial board house - not sure which one yet, but probably someone who will accept an Eagle .brd file.
> For the drill hole sizes of bigger components like 78XX Vregs, DIL ICs, Jacks etc. - if I go for the diameter of the component lead plus 10% - is that a safe working tolerance?

Producing a one-sided PCB is unlikely to save you money. You are
better off using two sides.

Since all of the PCB vendors accept gerber files you are better off
using gerber files. You will have more
vendor choices.

I would not use a percentage increase for diameter. I would use a
fixed number of mils (typically 5-10mils clearance).
Be careful of the PCB vendor specs. Some specify finished diameters
others drill sizes. If a drill size is specified you
need to account for plating thickness.

I have started a footprint reference document. Scroll down to the
"Footprint Reference Document" at

(* jcl *)


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