Not to be a downer, but any crib requires those slats to have no more than 2" between for safety reasons. The head can not get through but many babies have broken there legs and arms in those slats and choked. Whether your is defined as a baby crib may be debatable. You do not sell them so these codes probably do not apply to you, but they may.
I do not want to cause problems, but if your friends baby got hurt I imagine more than a law suit would be a problem. I am sure you would not feel to good about it.
I am just posting the rules enforced on all crib makers not commenting on the spacing myself. I believe these are updated 1999 rules.
Adjustable rails:
If a crib has a top rail that drops down to help place an infant in or take him or her out of the crib, to prevent the
child from falling out
(a) the top of the adjustable rail at its highest position must be at least 26 inches above the top of the mattress
support at its lowest position, and
(b) the top of the adjustable rail at its lowest position must be at least 9 inches above the top of the mattress
support at its highest position.
Slats, spindles, and other parts:
To prevent children from strangling because their bodies can slip through openings but their heads cannot,
parts such as slats, spindles, corner posts and rods cannot be more than 2 inches apart at any point, and
cannot be greater than 2? inches apart when a loading wedge test is performed.
Hardware:
Hardware accessible to a child must be designed and constructed so that it does not pinch, bruise, crush, cut,
break, or amputate any part of a child?s body during normal use, or with reasonably foreseeable damage or
abuse to the crib. Locking devices for dropside rails must require two distinct actions or a minimum of 10
pounds of force for release. Wood screws may not be used to connect stationary sides, dropside rails, folding
rails or stabilizing bars to crib ends or other parts that a consumer must remove during normal disassembly.
Construction and Finishing:
All wood surfaces must be smooth and free from splinters; all wood parts shall be free from splits, cracks, or
other defects that might cause a crib or any of its parts to fall off or come apart. End panels and sides,
including any attachments, cannot have any horizontal bar, ledge or projection with a depth greater than1/16
inch, or any other surface that a child inside the crib might use as a toehold.
Assembly Instructions and Labeling:
Every crib must be sold with detailed assembly instructions as well as identifying marks, cautionary
statements, and compliance declarations. Please refer to the regulation for the contents and placement of the
required information, as well as for the requirements for keeping records of the sale and distribution of cribs.
Cutouts:
To prevent a risk of strangulation, the crib regulation contains a test to evaluate whether cutouts such as
decorative openings sometimes found on the tops of the ends of a crib create a risk of head or neck
entrapment.
3. What type of mattress should I use in a full-size crib?
To prevent head entrapment and suffocation between the mattress and crib sides, a mattress used in full-size
cribs must be at least 27? inches by 51 inches with a thickness not exceeding 6 inches. The assembly
instructions, the retail carton for the crib, and the crib itself must contain a specific warning statement which
contains these dimensions. The mattress must fit snugly so that two adult fingers cannot fit between the
mattress and the crib side.
Here are slightly older standards not as stringent(1991 I think)but I guess are still good in some states: A 2 3/8" space is allowed.
Crib regulation
New rules are going to be voted on next month as decided on 11/10/2008. SO the standards are going to get even tougher.
Here are the federal regs:
CFR title 16, volume 2