Strip connectors padgap


#1

Hi,
I used ‘socket_strips:socket_strip_straight_1x11_pitch2.54mm’ for my connectors, but find that when soldering, there is a big gap between the PINs and the copper pads.
What’s the best solution please?
Camerart.


#2

Universal answer : create your own footprint.


#3

Are you saying you drilled the holes too big?


#4

@bobc might have the correct general answer.

Now the reasoning behind the 1mm drill size used in the official lib:
Most pin strips have a square cross section. For the drill diameter of 1mm, the largest pin can have a side length of ~0.7mm
Most such pin headers have pins with a nominal side lenght around 0.64mm [25mil].
Samtec for example suggests 1mm drills http://suddendocs.samtec.com/prints/xw-th.pdf for such pin headers.
This can be easily explained when you remember that both the drill and pin have tolerances. In fact if you use +/-0.05mm as tolerance for both you come tho the conclusion that the largest nominal pin side length that can be fitted in the worst case is ~0.63mm [~25mil]


#5

Hi All,
On closer inspection:
All approximate.
The PIN diagonal is 0.80
The I.D. of the copper is 1.08
I’ve been drilling 1mm

I only mentioned one Strip connector (1x11), but I use different numbers.
I’m happy to make my own footprints, but I’m surprised it is necessary, as the gap is quite large soldering wise.
Is it possible to have a global setting for pads?
C


#6

I don’t know which specific connector was the basis for the footprint, but if it wasn’t the same as the part you bought, then you need to make a footprint for your part.


#7

Why do you think i linked a samtec datasheet above? :wink:


#8

Was the Samtec part used for this footprint?

How would we know which specific part (vendor, vendor part number) is used for any given connector?


#9

These are intended as generic footprints. We used a number of datasheets to find dimensions that should fit most of them. But yes including at least one datsheet in the description might be a good idea.


#10

A little late now but a quick and easy check for through hole parts is to print out the design on paper and stick your components through. I think someone recently suggested a cardboard backing helps.


#11

If you can make accurate holes in cardboard.

I doubt this will help for wrong drill sizes. Might help for wrong pin pitch. (But maybe not even there. Especially not to differentiate 2.54mm vs 2.5mm)

I would suggest to load the footprint into freecad using stepup and then make a dimensioned drawing from it. (example using the drawing dimensions workbench)
You then simply compare this sketch with the one in the datasheet.


#12

[quote=“Rene_Poschl, post:11, topic:8755”]
I doubt this will help for wrong drill sizes.
[/quote]Try it and you might be surprised how well defined the punched holes can be. The card board idea was just for packing of the paper model to make it easier to poke through the paper cleanly. Something like corrugated would probably work best.


#13

Hi All,
Filtering all of your messages, it appears that I have to make each connector footprint I need myself.
Thanks.
C.


#14

I’m puzzled. If you are drilling your own holes, does it matter what the footprint says?

1mm is standard drill size for stripboard (aka Veroboard), I have been soldering that for years and never noticed any problems. Solder just flows around the wire.

Getting pin or socket strips aligned nicely is perhaps more tricky, some people stagger the holes so that the pins “lock” in the holes, personally I don’t like that. I prefer to solder one pin first, then align the pin strip.

Btw, creating a custom set of footprints for pin strips is very easy if you can get the hang of Python scripts. You probably just need to change one line to change the drill size. Or even do a global edit on the the existing footprints.


#15

There seem to be two common square pin sizes, the Samtec is the larger one. Important to know which you want as they don’t inter–mate well


#16

No.

It means that you have to verify that the footprints will work with the tolerances of your physical parts and your fab house.

Did you drill the hole sizes yourself; as has been implied?


#17

Hi S,
I’ve not come across ‘Fab house’ yet, but when I do I’ll remember your message.

As you can see by the two different sizes between Posts 4 and 5, I have smaller pins than the drawing. The PINs I have fit all of my connectors and Pickit3, so I’ll stick with them.

So I will most likely try a smaller drill, ‘say’ 0.8mm, and try to modify my global settings to make the hole, more of a centre dot, as I it will help me centre the hole.

Thanks to all,
C.