The grid in Eeschema is some nameless unit that should be left at the default of “50”.
Some time ago I bought a Cubie board, (Small Linux Computer, sort of like Raspberry pie). It has dual row 60 pin connectors with a pitch of 2mm.
Now try to fit that on Vero board with a pitch of 2.54mm.
I ended up putting connectors on the pins of the Cubieboard, and then soldering wires to the PCB. That was a real nuisance, but still, for a one-off experiment it’s not worth to design a custom PCB.
The solution is for prototyping board to be made to 20th century or later standards, not keep on moving backwards: -
Hole pattern: 2 x 2 mm (0.79mil)
Soldering islands 1.6 mm²
44 x 42 holes in rows
Hole diameter: 0.8 mm
I guess the conversion is wrong, should be 79 mil? I have learnt a new measuring unit already.
PRODUCT ID: 366 $0.95 IN STOCK.
As I say we will always disagree, argue either way, the world will not go backwards forever.
As it happens I have learnt something from this. I am now buying 2mm prototyping board and headers, I need to work on making adapters the Raspberry Pi’s though…
The file format is in mil. 1 EEschema unit is 1 mil. So you can not really use metric with the current file format.
Version 6 will come with a new file format and i suspect it will use the same unit as pcbnew allowing for both metric and imperial to coexist.
However, my hope would be to get fully rid of units in eeschema. Ideally eeschema would work more like a modern vector graphic program where you can scale symbols as you wish and use cool alignment features instead of the grid. Plus of course snap to anything features.
Now try to find some 2mm breadboards 
That’s right. The only problem is that there still must be a way to define physical size because the drawings may be printed physically. Otherwise we could use a nice trick: change the units but keep the values uncoverted. 50 mils would become 50 mm. That wouldn’t affect the design in any way.
Making it completely unitless would have another small - or possible a big - negative effect. Human beings are accustomed to using units for even relative sizes. The UI would be more difficult to understand and use if there were no visible units, be it in, mil, thou, lightyear, m, km, mm… Basically a number without units is an “amount, number”, not “length” for human beings.
All ready sorted, RS components,
https://uk.rs-online.com/web/p/matrix-boards/5167568/
RE130-LF, Single Sided Matrix Board FR4 with 44 x 42 1mm Holes, 2 x 2mm
Pitch, 95.89 x 90.17 x 1.5mm, and variations of that.
I must admit it is not an easy ride, but then whatever is? I found that
a lot of this is advertised as 2 mm, but then turns out to be 2.54.
Sorry if I have upset the group a bit, but I have had an aversion to
imperial since I sat in class wondering why we were being tortured with
this when even then I knew of a better system. That would have been in
the mid 1950’s, I have been fighting ever since.
The basic problem here is largely down to the original IBM PC
specification, still plaguing us today with those 10-32 or whatever
screws, inch drives that probably were never inches, and my real pet
hate, the red wire being 5 volts, not 12 volts, lost a few things to
that one!
Anyway, nice to get an email of any sort, I don’t think you will see any
more of me from now on, I have had my say and grateful for what I
already have, vector graphics would be good though.
I thought that schematics were scaled to papersize during printing.
When you select an A2 sheet, the sheet does not get bigger, but the components get smaller when printed.
I do like grid based schematic entry though. It may have some disadvantages, but it keeps things lined up neatly with minimal effort.
The grid is also baked into all library symbols. Having IC’s with (slightly?) different pin spacings would be too weird an obstacle to overcome for me.
A grid size of “1” for the default pins spacing would be slightly preferable to the “50” it is now, but I don’t really care what number it is, just as long as it’s consistent, and that it is thanks to excellent efforts from the Library maintainers
[Edit]
Oops, Default pin spacing is 2 grid points, so normal pins spacing is “100”, which is a fine round number for me.
@brianac
Have you seen the size of that board you found, and the spacing of the mounting holes. Have you found a breadboard yet with 2mm spacing?
A few of those 2mm boards may be nice to have, but most breakout boards (and old IC’s, which are still possible to buy) fit on a 2.54mm grid.
All those cheap Chinese “matrix boards” with 2.54mm pin spacing have round numbers in mm for their outlines.
I believe the British switched from miles to km for road signs just some short years before Brexit. I’ll wonder when (if?) they will turn that back. At least they’re still driving on the wrong side of the road.
A good point, why is the default grid not just “1”
Then going bigger or smaller (for graphics only) looks more like a zoom function, which is what it is for most purposes
I would not suggest the use of the smallest unit as the default grid. You want a rather coarse grid for allowing to create connections easily. And you want smaller grids available to add finer details to your symbols.
Experience taught us that the second largest grid is a good option for the default grid. It allows a bit more flexibility than the largest grid option but is still coarse enough.
Combine this with the fact that you rally want your file format to use integers not floating points which means you can not really use decimals.
In that case call the default 100(%) and allow integer from, say “1” to “1000”
I suppose my main point is that it should be a multiple nag step process to change it from default for wires and pins.
To this day a large proportion of schematic related posts on this forum are caused by beginners using a small grid.
I already edited my posts before you wrote this,
Eeschema pin spacing is on a “100” grid. The “50” visual grid in Eeschema are “half pins”.
“100” is a fine round number for me.
The gird unit doesn’t have to be the same than the internal unit - the grid could be “1” by default which would be e.g. 100 internal units.