There is a groove 0.281 inches wide and 0.371 inches deep
A tubular shaped item with a round or hexagon peripheral shape having two flat bearing surfaces perpendicular to the axis of the centrally located hole. It is designed to maintain a predetermined distance between assembled parts. The item may be with or without flange(s) of any peripheral shape. The overall length must exceed 25 percent of the outside diameter or distance across peripheral flats of the body. (when the length, outside diameter, and/or distance across peripheral flats are designed as a tolerance, the maximum dimension will be used to determine compliance). For items having other than a round or hexagon peripheral shape, see spacer, plate. Excludes items with lubricating features, see bearing, sleeve and bushing, sleeve. See also bushing, tapered; spacer, ring; washer, flat; and washer, (as modified).
Classification: Other articles of iron or steel not wire nesoi
NSN 5835-01-320-8306
NSN 6320-01-495-1244
NSN 5895-00-941-2960
NSN 7035-01-294-2688
NSN 5960-01-539-1956
NSN 6110-00-065-4742
NSN 5999-01-062-0739
NSN 6650-01-522-0075
NSN 5910-01-456-4633
NSN 5930-00-409-3591
NSN 6685-01-592-4098
NSN 6620-01-069-0912