Homebrew PCBs

----- Original Message ----- 
From: "Harvey White" <madyn@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, July 09, 2008 9:04 AM
Subject: Re: [Homebrew_PCBs] Re: Eyelet press recommendation


> On Wed, 09 Jul 2008 12:37:02 -0000, you wrote:
>
>>--- In Homebrew_PCBs@yahoogroups.com, Harvey White <madyn@...> wrote:
>>>
>>> On Fri, 4 Jul 2008 13:14:10 -0500, you wrote:
>>>
>>> >>>I use eyelets (0.050 diameter), copper, and then separate vias
>>>
>>> >
>>> >What do you mean "separate vias" ?
>>>
>>> A via is used only to connect the top and bottom layers, but not at a
>>> parts lead.  That way, I do not have to worry about the hole in the
>>> eyelet.
>>
>>If you use separate vias, why bother with an eyelet? Just
>>insert a snipped off lead (from a resistor, or cap?) and solder
>>on both sides. Or am I missing something?
>
> The wires falling out of the holes.  Simple "wire through" does not
> work well for me, the wire ought to be properly bent over (and is a
> bit awkward to do).

Uninsulated bus wire is cheap (~ $20/100'). "Sew" a long length through 
several vias, solder both sides, and snip the excess; repeat. They're not 
quite flush enough to fit under an SMT footprint. If you're careful, you can 
get away with it under an SO part, but that's almost begging for trouble.

Eyelets would be useful for through hole headers, jacks, etc. anywhere the 
component side is inaccessible under the installed device. The trouble is, 
eyelets are too wide for .10" pitch, making them useless for almost 
everything, including .10" header rows. I often bring up the solder-able 
bottom trace where needed with vias. So, it begs the question: why? You 
drill and fill 2 holes where 1 should suffice. The ubiquitous 2x header rows 
are cheap and easy to keep on hand. They are superior for this reason alone. 
The alternative is keeping an assortment of SMT headers, 3x to 10x more 
expensive even counting the eyelets you can't use, and you never have the 
right size in the part box. Right angle headers work with paste and hot air, 
but are seldom what I really want. I use special bottom-pad only footprints 
for straight headers. Mechanical anchoring is compromised, but not an issue 
for long rows. For everything else, SMT works best for many reasons.