CHASSIS METAL WORK

Weld Slag and Spatter

Weld slag shall be removed before application of finish, evidence after finishing is cause for rejection.

Weld spatter on a mounting surface is cause for rejection; permissible on all other surfaces.

Burrs If present, burrs shall not exceed the limits of paragraph

Removal of burrs shall comply with the requirements of the previous paragraph

Corners

Corners shown sharp on a blanked part may be produced with a radius, chamfer, or break complying with paragraph.

Sheared Edges

A sheared edge shall be square within 10⁰  

The extreme edge as illustrated in before shall be used when measuring to or from the edge.

Squareness  

Unless otherwise specified, sheet metal cabinets, panels, doors, chassis, etc. (over 12" in the smallest dimension) shall be square within .015 in/ft. not to exceed .12 max.  Squareness to be within dimensional limits.

Squareness of a Right Angle Bend

Unless otherwise specified, 90⁰ forms 1 inch or under in length shall be square within the locating dimension.  Forms beyond 1 inch shall be square within .005 in./in. of bend length.  The long leg is considered to be datum.  Squareness of structures, fabricated by welding or riveting together sheet metal and or structural pieces shall be square and free from twist or lean within tolerance.

"U" Forms - Legs of the "U" form shall be square to the common axis of the two datum holes within .005 in./in.   Squareness is measured radially from the common axis.

Edge Squareness

Between two sheared edges or two formed sides, the squareness shall be within .015" per linear foot.  Between a sheared edge and a formed side, the squareness shall be within .020" per linear foot.  Dimensional tolerances shall apply if tighter.

Intersecting Surfaces Shown at 90⁰

Unless otherwise specified, intersecting surfaces shown at 90⁰ shall be square within the tolerance on the dimension of the longest surface.  The long surface is used as the datum for checking squareness.

Parallelism

Surfaces

Unless otherwise specified, the parallelism of surfaces shall be controlled by the tolerance of dimension between the two surfaces.  The longest surface shall be used as datum. 

Sheet metal cabinets, panels, doors, chassis, etc. (over 12 inches in the smallest dimension) shall be flat within .03 in./ft. not to exceed .12 max.  At any point flatness variation shall not exceed .03 in./ft. applied over a smooth curve.  Flatness includes dishing, bow, and twist.

Bend Line Straightness

Unless otherwise specified, bend line shall be straight within .010 in./ft. not to exceed .06 max.  At any point the straightness variation shall not exceed .010 in./ft. applied over a smooth curve.

Mounting Plane Flatness

All points on members which form a mounting surface shall form a true plane surface within the limits. All points within a 12" x 12" area must form a plane within .016, and 24" x 24" area must from a plane within .031", and the entire surface must form a plane within .062".

Grain direction shall be perpendicular to formed bends unless otherwise specified.  This minimizes crazing or material fracture on bends.  

COMPONENT ASSEMBLY

General - Card cages, doors, panels, side plates, electro-mechanical subassemblies, cabling and hinge/latch/locking mechanisms shall conform to the requirements specified herein or as required by referenced paragraph.

Damage

There shall be no damage beyond the limits specified in applicable sections of this document.

Hardware Assembly Sequence

Acceptable

The sequence of mechanical hardware assembly conforms to specific product documentation.

Unacceptable

Any deviation from product documentation.