[Al Skierkiewicz]

Everyone,
Be careful here..
The rule states that bumpers must be mounted on the FRAME PERIMETER. The FRAME PERIMETER is explicity described in the rules and can have minor protrusions for boltheads, rivets and welds not to exceed 1/4". The bumper must be outside this perimeter (and mounted on it) but can have recesses to facilitate secure and robust mounting of the bumper system to the frame. Any method of using the bumper to hold parts in place must comply with this rule. If the bumper system is backed with metal plates and the plates are used to support other robot structure, than the plates become the frame perimeter and will be inspected as such.
See R2 and R3 and section 4.6 of the robot manual.
The First base kit when correctly assembled will have axle bolt heads that extend out of the FRAME PERIMETER but these are allowed (see above). When incorrectly assembled (bolts reversed), the bolt ends and nylon lock nuts would extend beyond the allowed FRAME PERIMETER protrusions limit of 1/4". The accepted method for determining FRAME PERIMETER is the string method as described in the rules.
Additionally, any parts that are FRAME must be weighed with the robot not with the bumper system. Bumper systems that use metal plate attached to the plywood/wood backing (for mounting purposes or other legal reasons) must meet all bumper rules including weight, and "hard parts" limits.