How to get a real custom grid?

[D.E. Main]

I'm designing a graphic that needs to be quite precise - to .1 mm.  So I need a 3.3 x 3.3 custom grid with snapping.

So document is set up with mm.  In GRID AND AXIS MANAGER, in advanced, uniform - it will not allow me to type in any entry and the dropdown slider only goes in specific increments.  For example, I can do 3.19 mm and 2,8m but nothing in between.  I must be doing something wrong.

Any suggestions?  What am I doing wrong?

Many Thanks

 

[G13RL]

Click in the "Spacing" window and type in the desired number.

[D.E. Main]

Argh.  This is where I was typing and it would not take.  I reopened Designer and now it works.  I had something wrong, but works now.  Thanks.

Thanks,

D