Soldering Headers Without Drilling Holes

by rampadc

16K10613

Intro: Soldering Headers Without Drilling Holes

Unless you have a drill press, drilling holes for homemade PCBs is a hassle. Not only the drill bit is quite fragile at 0.9mm in diameter, drilling holes off-center would also throw off alignment, making it difficult to insert and solder. Since I mostly work with SMD components, using through hole headers also create the headache of through-hole plating. Of course there are SMD male and female headers available for purchase but each SMD header pin is usually 10 to 100 times more expensive than normal through hole header pin, even at when bulk bought at the quantity of 1000.

This method is used everywhere since it's not new. It's just that people don't tend to think to use of these sort of solutions unless they're cornered.

STEP 1: Place Down the First Blob of Solder

Put down a blob of solder onto the first pin you want to solder. Since I'm right handed, I prefer to hold the soldering iron with my right hand and hold the pin header with my left hand using a pair of tweezers. Thus I solder the right-hand side of the header first.

STEP 2: Solder the First Pin

Heating the blob of solder with the iron into liquid form, align the desired pin of the header in it and make sure to align the rest of the header with the header footprint. After removing the soldering iron, keep holding the header in place to ensure the alignment is secured as the solder solidifies.

As you can see, the header does not have to be perfectly aligned on top. It doesn't even have to touch the PCB.

STEP 3: Solder the Last Pin

The most outer pin on the opposite side is then soldered to hold the header in place before the rest of the header is soldered. This is being done instead of soldering the immediate pin because if the soldering iron tip is big enough, it may melt the previously soldered pin. The header may fall over and you would have to start over.

STEP 4: Solder the Rest

After the header is securely soldered, the remaining pins are soldered.

STEP 5: Final Product

There you have it! The ability to solder through-hole pin header without having to drill a single hole! The above photo shows a recent breakout board of mine having a total number of 22 header pins soldered with this method.

13 Comments

Vitim 9 years ago

Not a good idea, you could have routed the traces to the edge of the board and soldered then flat.

JanC2 9 years ago

Guys, don't do this if you plan to plug/unplug anything to these headers. A slight amount of lateral force over a few connect/disconnect cycles and the thin tracks will give way and peel off, destroying your board. It is not a mechanically sound way to mount these headers.

rampadc 9 years ago

If you solder these pins properly, a lot of force, much much greater than connecting jumpers, would be required to break them off. If you're still worried, use bigger pads.

JanC2 9 years ago

The problem is not a one-off force, which would have to be, indeed, quite significant if there are many pins and they are well soldered.

The issue is the periodic stress on the solder joints and pads over time as things are connected and disconnected from them slowly weakening the joint. Sooner or later the pads will give way and ruin your board. That's why you will never see this type of lazy soldering in anything commercially made - it is a ticking bomb reliability-wise.

If you don't want to drill holes, use proper SMD headers instead. They have the contacts flush with the board and much larger surface area compared to the vertical pin of a regular header. They are also much less tall as they don't have to go through the board, thus reducing the amount of stress on the solder joint (less torque due to shorter lever).

rampadc 9 years ago

I'm not trying to argue with you about best practices here. This is just a solution to one of those moments when someone doesn't want to drill holes and doesn't have SMD headers in-hand.

rampadc 9 years ago

This is used for testing. This sort of thing is inadequate for commercial products

EdoNork 9 years ago

Couple ideas:

- Make pin footprints without holes, more place for solder to stick.

- Place the two pin rows in a little breardboard fist (oposite side from solder), they will be perfectly aligned, they will not move from correct place and weight will snap them to footprint when solder melts.

ElektroQuark

rampadc 9 years ago

the first point is a good recommendation, though second point would work but you run into the risk of melting those pins on your breadboard

Tinydot 9 years ago

Nice solution, drilling holes is always the worst part of any DIY PCB

Though I do wonder how sturdy those connections are? Granted, once everything is in a fixed setup or if it's a prototype board it doesn't really matter much.

An alternative that I've used is laying the pins flat at the side of a board, though you do have to design your board for it (See picture).

If you use angled headers (http://tinyurl.com/nunm7b6) , you can do it on any place on the board and still have a large contact area.

Keeps you from having to stock specific through hole as well as SMD headers, which is great as any desk always turns into a wall full of part bins.

rampadc 9 years ago

The connection is sturdy as long as you don't stress test it by apply a lot of force pushing the headers side-ways. I have thrown it around a bit and dangle the PCB on a jumper wire. It has been holding up well enough.

The connections can be stronger if I add more solder and maybe remove the to-be-drilled hole footprint from the PCB and leave it as a solid copper circle.

I've thought of using right angle header but that requires making a new PCB footprint. So far, this method has been working well for me, so I haven't got any incentive to use other alternatives.

Those vias looks very professional, though isn't it a bit pointless to do vias that small while you're trying not to drill 2.54mm headers?

Tinydot 9 years ago

Nice to hear that it's still sturdy enough, thanks for the reply! I'll keep this in mind for my DIY at home PCBs in the future as well in that case.

Actually the board in my picture could only be populated on one side as the other had to be a flat sensing surface. Since then I've done the same on DIY boards, I just already had this picture from another project. The main reason here was not having to get any new connectors, opposed to drilling holes. I just figured it would be a nice additional method.

rcbailey 9 years ago

Some hot melt glue on either side of the header pins would probably add some mechanical strength.