@MakeShip That would work if he has one to measure. I’m guessing he doesn’t, and I’d hope someone with an X-carve can just help.
I think this is a trick question.
Assume it is a photo of a wasteboard and that he does have the actual board in front on him. Can someone answer the question. My board is home made
17mm is what my board measured.
here are the design files.
A Fond Farewell to GrabCAD Workbench - GrabCAD Blog
by using the math listed on these it says that the bottom of the holes on the first row are 18.25mm from the bottom of the board. the silk screen looks to be about 1mm below the bottom row of holes.
Haha! No. I have calipers and rulers and measuring tapes everywhere.
By “one” I meant an X-carve wasteboard, not a ruler.
I assume the OP is trying to mark his own gridlines on his own homemade wasteboard. In the end it probably doesn’t matter as they’re just a guide. I don’t know how precise a silkscreen placement can be.
I measured mine from the outside of the waste board to the outer edge of the line, I see that you measured from the outside of the waste board to the inner edge of the line. that should mean that the printed line is 1mm thick.
Just wanted to answer that one before the next question is asked. 
got my calipers out and they measured 10mm in each direction.
See now, I live right in the middle of good ole America, and as such I am really struggling to use that new fangled metric system.
One of the biggest problems I had was That i wanted to convert everything to inches and feet. Once I decided to use metric or imperial and to keep them separate it became very easy to use the metric system. Now if I see a set of plans in metric, no problem. I just use only metric. Same when I see a plan in feet and inches.
The only thing that I really hate is having to have two sets of tools when working on equipment. I also still find it difficult when going to the local stores looking for anything metric
sorry I forgot to use sarcastic font in that reply. was not meant to be taken seriously.
I am a post secondary vocational teacher in a automotive tech school and have to deal with imperial to metric conversion every day.
edit: my life would be so much easier if we all just advanced to the metric system like they promised 35 years ago. but we won’t so I deal with it.
94 mm