Homebrew PCBs

Hi All,

I am looking for some method to plug a pre-made device into a hole to 
work like a plated thru hole.

I remember some discussion of this last year and there was some 
supplier who evidently doesn't have a US supplier.

What do you do for the one's and two's of getting both sides of a 
board to have a connection.

This really only applies to things like DIP chips where one cannot 
solder under hte part.

TIA.

Dave

----- Original Message ----- 

From: "Dave Mucha" <dave_mucha@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, January 14, 2004 6:47 AM
Subject: [Homebrew_PCBs] Source for Pins instead of plated hole - revisited


> Hi All,
>
> I am looking for some method to plug a pre-made device into a hole to
> work like a plated thru hole.
>
> I remember some discussion of this last year and there was some
> supplier who evidently doesn't have a US supplier.
>
> What do you do for the one's and two's of getting both sides of a
> board to have a connection.
>
> This really only applies to things like DIP chips where one cannot
> solder under hte part.

With DIPs it's easy to solder the pins on the top and bottom of the board. I
often do this for ground connections with RF boards with a continuous ground
plane on the top.

It is just about possible to solder turned-pin sockets like this, but not
very neat.

Leon
--
Leon Heller, G1HSM
Email: aqzf13@...
My low-cost Philips LPC210x ARM development system:
http://www.geocities.com/leon_heller/lpc2104.html

if you need to still use the hole for a component leg i only know two 
methods.

the first method is thin walled copper tubes, filled with tin.

the tin holds them together but the copper is cut to small lengths already.
you insert such a cylinder in a hole and then kind of rivet it in.
the tin presses the copper aganst the hole walls.

when you have riveted the whole board you suck the tin out of the hole and
it should look like a throughhole-plated board.


the second method is using small rivets.
tiny hollow rivets are inserted into the (slightly bigger drilled) hole and 
either riveted in place or just soldered. the manufacturer claims even 
without soldering the riveting
action alone provides enough reliable contact.

the disadvantage of both methods is that it is realtively expensive.
i would try the rivets if i needed, but until now i could live without.


for the costs of the rivets i can easily make a board double the size, 
where it is then obviously no problem
to solder both sides.


In 99% of the cases i try to make single sided boards.
even in worst case (all smd) it should be possible to do it in less then 
double the area.

it is just a question of good part placement and good routing.
(sure with more complicated boards it is impossible but....)

st

I explain this procedure on my website:
http://www.pic101.com/pcb/thru.htm
Rick

Dave Mucha wrote:

>  Hi All,
>
> I am looking for some method to plug a pre-made device into a hole to
> work like a plated thru hole.
>
> I remember some discussion of this last year and there was some
> supplier who evidently doesn't have a US supplier.
>
> What do you do for the one's and two's of getting both sides of a
> board to have a connection.
>
> This really only applies to things like DIP chips where one cannot
> solder under hte part.
>
> TIA.
>
> Dave
>
>
>


[Non-text portions of this message have been removed]

--- In Homebrew_PCBs@yahoogroups.com, "Rick C." <rixy@V...> wrote:
> I explain this procedure on my website:
> http://www.pic101.com/pcb/thru.htm
> Rick

As a technician, I can tell you that those rivets are indeed a
terrible source of problems. They expand and contract and cause cracks
in the solder, and when resoldering they must be completely sucked out
and carefully resoldered so there are -no- bubbles. If even one bubble
pops out, it makes a cold solder joint and must be redone.

And it's almost impossible many times to find the cracks in the solder
around them by visual inspection.

Steve

>
> As a technician, I can tell you that those rivets are indeed a
> terrible source of problems. They expand and contract and cause cracks
> in the solder, and when resoldering they must be completely sucked out
> and carefully resoldered so there are -no-bubbles. If even one bubble
> pops out, it makes a cold solder joint and must be redone.
>
> And it's almost impossible many times to find the cracks in the solder
> around them by visual inspection.
>
> Steve
>

That is good to know.
Obviously the ad doesn't say THAT.

st

Dave Mucha wrote:
> I am looking for some method to plug a pre-made device into a hole to 
> work like a plated thru hole.
> 
> This really only applies to things like DIP chips where one cannot 
> solder under hte part.
> 

   Others are hitting the disadvantages, and just as much as that there isn't 
much gain from these things.

   If you need an exact board like you want a production board later, then you 
really need a thru plated prototype board anyway.  The only thing these do for 
you is let you put a PIN in the hole too.  If you're not doing that, then you 
may as well have just used a piece of wire in the first place.

   For homemade boards you should be grouping your vias as much as possible 
anyway.  Under or outside the chip outline, you should be putting them into 
lines or blocks anyway.  Skipping spaces of course but still with an overall 
line to follow so they're easy to see.  Put spacers on the bottom of the board 
when doing the vias, and use regular wire.  Do it on a hard surface with the 
spacers, and insert wire, solder, cut, then insert, solder, cut, etc.  You know 
you've soldered the top side, flip over bend the extra the spacing made so they 
don't fall through, and solder the bottom.  If these are in groups or lines you 
can do them in a hurry, and no need for some special pins or tubes.

   There is also someone that makes small nails that aren't hollow, but still 
the same "no real advantage".  I haven't seen one system that looked like it was 
really any better than just wires.  The tubes are neat for homemade, but when 
you think about the extra time and how rare (like never) you should ever need to 
put a pin through one if you design for it, they don't make sense for the prices.

Alan

Dave:  

Just happened to read your inquiry re "PTH pins", and I haven't read further, 
yet, to see if one or many more "in here" have already responded, but here's 
MY 2¢ worth:  I bought a quantity of tiny gold-plated "swageable eyelets", aka 
"rivets", which are a lot of bother, but if you just MUST have a PTH or two, 
but can't go to the expense of having a board plated through after drilling 
(for only a few PTHoles), then the bright solderable eyelets are the way to go.  
I turned my own "swage tool" which spreads the "insert-end" so it is tight, 
and then one must solder BOTH sides of the rivet before installing components.  
If the I.D. gets filled with solder, I heat it again and tap one edge of the 
board on the bench, the inertia "shooting" the molten solder out fine.  

For a "PTH" for an IC-pin or two, and you don't want to solder BOTH sides of 
the pin (fear of overheating the IC, so close, for example), try installing a 
tiny piece of #28 (or #30) silver-plated wire-wrap wire, solder it carefully 
on top before inserting the IC.  OR, IC-socket, which would preclude ANY 
soldering on top after installation!  the flat IC (or socket) pins will allow 
inserting both the IC "leg" AND the small-dia. wire in same hole.  

Sad PTH is such a difficult "professional fab-house" job, isn't it!  

Jan Rowland


[Non-text portions of this message have been removed]