Finished socks should be tested both before and after 3 launderings (following AATCC test method 135).
Stretch socks must fit both the lower and upper ends of a specified size range. For example: 9-11 sock must neither fit too loose on size 9 form nor too tight on size 11 form.
Each sock can only be sized one time and the order of sizing must always be smaller NAHM first then larger NAHM board.
Board selection for lower end of stretch sock sizing range
Select the NAHM form representing the lower end of the intended sizing range. Pull the sock on the form without stretching the fabric and then smooth out the wrinkles. If heel gore is present on the sock, align it with the board heel or the two holes at the board heel if present. The sock is sized correctly if the sock touches the sides of the board all around the foot without excess fabric hanging off the board and the sock top is located at your correct specified point on the leg portion of the board.
Board selection for upper end of stretch sock sizing range
Select the NAHM form representing the higher end of the intended sizing range. Pull the sock on the form stretching the sock fabric to maximum extension without breaking the sock fibers. The sock heel should extend beyond the board heel gore and return to the gore when the fabric is slightly released. The sock is sized correctly if the sock heel gore is aligned with the board heel or the two holes at the board heel if present and the sock top is located at your correct specified point on the leg portion of the board.
Special addendum on Use of NAHM Sizing Boards (Upper End):
In order to meet relaxed layout requirements for socks where elastic yarns are used for plating, sock sizing ranges may need to be adjusted. For example, it is possible to make socks that fit a broader size range than just a 9-11 and meet a determined relaxed layout. A sock could still be considered to fit a size 9-11 even though it would fit a size 12 on the upper end. As long as the sock will still fit the size 9 without excess fabric at the toe on the board, the sock could fall into the 9-11 category. The labeling would simply not reflect the socks total size range. The extra fabric would satisfy the relaxed fabric requirement while at the same time extending the fit range. The choice is between the manufacturer and retailer on the fit range used for the labeling.
Non-Stretch socks must be neither too loose nor too tight on the size specified. For example: a size 10 sock should fit a size 10 form.Refer to the NAHM Sizing Standards Brochure Revised November 1990 for background material used in developing the NAHM Sizing Boards.