[sdiy] PCB drill size tolerance

[Merv Thomas]

Hi,

You should probably check with your chosen board shop to see if they have a 
recommended 'standard' range of hole/drill sizes as some shops will charge 
you a premium if you use something non-standard. As John says something like 
5 - 10mils (~0.2mm) up from the pin size will usually work. As a rule of 
thumb, I'd work with 0.8, 1.0, 1.2 & 1.6mm (or whatever the imperial 
equivalents are). These'll cover most eventualities. Whether you're going 
single or double sided, I'd specify finished size for your holes and leave 
the actual drill size to the board shop. Can't disagree with John's comment 
about single v double sided either, the default process these days is double 
sided, plated through so you may as well take advantage of it.

Merv


----- Original Message ----- 
From: "John Luciani" <jluciani at gmail.com>
To: "Justin Owen" <juzowen at googlemail.com>
Cc: <synth-diy at dropmix.xs4all.nl>
Sent: Saturday, November 08, 2008 3:32 PM
Subject: Re: [sdiy] PCB drill size tolerance


> 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
> http://tinyurl.com/5bxzgh
>
> (* jcl *)
>
> -- 
> http://www.luciani.org
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


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