Hi All
Like many users, i use the 2.54mm pin headers for JTAG and various external connection.
My hole size are 0.9mm.
I have small issue when i am soldering the pins that i need hold them in or they would fall out.
For this i guess i would need to decrease the hole size.
What size does anyone use?
Your pin header should have a datasheet, can you post a link?
From that you can determine what hole size to use.
Jim
we use 0.95mm typical.
You want to have some room for tolerances. pin thickness. pin not 100% straight. tolerance on pin position.
I always hold the components when soldering, I first press on the connector on one side then solder a pin on the other side, so you do not make contact with that pin. then carefully put my finger on top of the connector as much a possible trying to not touch the just soldered pin. press on the connector and shortly heat it again to put the connector flat on the pcb. then you are good to go and solder the rest of the pins. Starting from the opposite side of the connector and pins.
I do use a large soldering tip so the tin heats quickly and then you can let go again quickly most of the times before the heat has reached the piont were your finger is.
I just use low-tack masking tape.
I always install the lowest height parts first, so I can turn the board over to solder through hole parts, but who uses TH parts these days, SMD is so much easier to do.
Jim
Hi Jim
Do not have a datasheet as purchased a good qty from ebay. They are simple the following:
Do not have a datasheet
Then you'll just have to do it by trial & error!
Different manufacturers & product lines do vary - that's why it's important to have the datasheet for the particular part you are actually using!
I do as Jim said - turn the board upside down.
Or you could bend the pins out slightly after inserting them.
Or "tack" the header in by a couple of pins - as meslomp said.
Or use some sort of glue - as Brian
etc, etc, ...
Then you'll just have to do it by trial & error!
Or use a micrometer and take careful measurements, although with a source like that, you may not get the same thing each time....
so you will have to error on the side of caution (larger hole size) and handle each one as needed.
Good luck with your project.
Jim
with a source like that, you may not get the same thing each time....
I'd say you are unlikely to get the same thing each time!
And know that with thickness of the solder, etc., lining the plated through hole, hole, to hold the pins also has a variable thickness, and can vary a lot between different PCB manufacturers.
I had a PCB where the holes were very tight and it was a challenge to force the headers into position, what a hassle!
Having the holes a bit too large is better, you just hold the header in place while you solder the first pin, or do as the others have mentioned above.
JC
Edit: For clarity.
In general, for good electrical connections, there ought to be enough "wiggle room" in hole size for TH componens that molten solder will wick through the hole and attach both sides, right? You don't really want the fit to be "tight."
(I like the sparkfun hack!)
I usually use 1mm "drill" in EAGLE for the 0.025in square posts; I'm not entirely sure what that turns into on a finished board (after plating, but also potentially after the board shop increases hole size to account for plating!)
SAMTEC, whom I'd assume is pretty authorative, says 40mils (1.03mm)...
Like Midwest Jim, I solder low parts first. Then I put in a header, turn it over, holding in the header with a finger, then let the weight of the board push against the square-pin. If the board is not parallel to the work bench, I may prop the board up, or make sure the connector is normal to the board. In either case, I solder one pin, then lift the board and reheat that pin if everything is not square. Only then do I solder the remaining pins.
But, yes, square pins are not created equal. And there is always the issue of "drill size" in the layout. OSH Park seems to take that as the finished hole size. Some appear to take that literally, as the actual drill, in which case, you need to allow for the copper build inside the holes.
West Coast Jim
The Sparkfun approach of staggering every second hole minutely works very well. I have used it via their Eagle component library many times. Recommended.
I usually use 1mm "drill" in EAGLE for the 0.025in square posts; I'm not entirely sure what that turns into on a finished board (after plating, but also potentially after the board shop increases hole size to account for plating!)
SAMTEC, whom I'd assume is pretty authorative, says 40mils (1.03mm)...
Normally you specify the "end size" of the hole ( so the word drill is misleading here) . The PCB manufacturer will compensate for how much copper they add to the hole on average. So the hole should for sure be always at least the specified size.
This is done because the customer in general does not know what the manufacturers specifications are in that respect. In addition this is why the Annular ring specification is so important. It counts for the drill location tollerances ( this is absolute with respect tot he 0 point of the PCB) and for the potentially increased drill size to still make a good solid via.
Sometimes it's possible to use a piece of prototype board as a clamp. For example if I'm building something on those cheap 5cm x 7cm boards with 0.1 inch pitch holes. What I do is put the headers in the board to be soldered then put another piece of the same board on top of the headers on the component side. Then use a couple of bulldog clips to hold the sandwich together for soldering. It works best if there's more than one header on the board.
