How to use 100mil grid with default libraries in Eeschema?


Is it possible to use a 100mil grid in Eeschema with the default symbol libraries?

I’m just starting out with KiCad and I’m accustomed to using a 100mil grid from previous CAD tools, but it seems like the default KiCad libraries require a 50mil grid in the schematics (although I’m not sure how to reconcile that with the KLC requirements in i.e. “Using a 100mil grid”)

Is there an easy way to work with a 100mil grid without creating my own libraries where all pins are aligned to a 100mil grid?


Short answer, “No, not always.”
The KLC does make some allowance for some parts to be on the smaller grid.


In this specific instance I think you could switch to the 50 mill grid, move the resistors, and then switch back to 100 mill. It’s just a number and one had to be chosen to make everything compatible. Shouldn’t take much getting used to. Other than that, yeah, make your own libraries. 100 seems a little course. Actually 50 seems a little course to me. I generally switch it to a smaller one at the end to pretty up text positioning.


Moving the resistors works temporarily, but as soon as I move the resistors or rotate them, they revert back to the 100mil grid with all the pins off-grid.


Looks like it’s not really practical to use 100mil grids if you want to use the standard libraries…I’ll just switch to using 50mil grids in KiCad.

However, this makes me wonder why KLC S4.1 bothers to require “Using a 100mil ( 2.54mm ) grid, pin origin must lie on grid node (IEC-60617)”? Why isn’t this requirement 50mil grid instead, given that standard parts in the library don’t follow this 100mil rule?


For the resistor (and some other symbols) you can use the one with _small prefix as it is on 100mil grid. (But this is not true for every symbol)

So for some of them you will need to make your own symbols or accept that you will need use 50mil grid.


That’s a good question. Many parts actually use 50 mil, the reason is to keep parts more compact. It is very confusing though to have a “rule” which is routinely not followed.

Personally I use 50 mil grid, and I’ve no idea why IEC-60617 prescribes a 100 mil grid. Perhaps it is like speed limits? Everyone drives safely +15 kph over the limit, but if you increase the limit to reflect that, everyone will drive +15 kph over the new limit, and maybe not as safely…


100 mills always fall on the 50 mill grid but not vice versa.


Of course, that’s how maths works :slight_smile: Your point being what exactly?


I think it was an incomplete answer to this. The other part was kind of answered before. I know what I mean/meant and that’s all that matters to me. :wink:


I did not time it, but I believe it took me less then 1 minute to change the resistor symbol.
1)Hover the mouse cursor over the resistor symbol.
2)Depress “Ctrl + e” on the keyboard.
3)Hover the mouse cursor over one of the pins.
4)Depress “e” on the keyboard.
5)Edit the “Length” field to have a “0.1” value; depress “Enter” or click “OK”.
6)Hover the mouse cursor over the the pin and depress “m” on the keyboard.
7)Move the pin onto the 100mils grid (this will also align the pin with the body); depress “Enter” or left click with the mouse.
8)Repeat steps 3 to 7 for the other pin.

The point being that this is a great start for someone to begin creating their own custom libraries.