1. Bolts, Screws and Studs
	Hexagon                           		 X)
     	Round                             		 R)
     	Mushroom               				 M)
     	Cheese                            		 C)	Single letter
     	Plain                             		 P)
     	Flat Countersunk          			 K)
     	Raised Head Countersunk 			 D)
     	Stud                              		 S)

    	Nuts
    	Self-Locking                     		 L)
    	Plain                        			 A)	Single letter
 	Nyloc                              		 Y)

	Washers
	Shakeproof                      		 L)	Single letter
	Plain                               		 A)

	2. Bolts, Screws and Nuts
	U.N .F.                             		UF)
	U.N.C.                          		UC)	Two letters or digits
	Metric                    			MM)

	Screws
	Wood                          			WD)	Two letters or digits
	Self-Tapping             			ST)

	Washers
	Internal diameter in        	  		 ')	Two digits
	16ths. inch or millimetres	   		  )

	3. Bolt          				 B)
	Screw                 				 S)
	Nut                                 		 N)	Single letter
	Washer                              		 W)
	Stud                                		 T)

	4. Bolts, Screws, Nuts and Studs
      	Diameter in 16ths. inch or millimetres		  ) Two digits

      	Plain Washers
      	Outside diameter in 16ths. inch or millimetres 	  ) Two digits

      	Shakeproof Washers
      	All sizes                                  	00) Two digits

      	Self-Tapping Screw and Wood Screw
      	Number                                    	  ) Two digits

	5. Bolts and Screws
      	Length in 16ths. inch or millimetres          	  ) Two digits

  	Nuts
    	Full                                           	 F) Two letters
    	Half                                          	 H)

    	Plain Washers
    	Thickness by .01 inch                          	  ) Two digits

    	Shakeproof Washers
    	All sizes                                   	00) Two digits

	6. Studs
	SUCC		UNC both ends			  )
	SUFF          	UNF both ends                	  )
	SUFC          	UNF one end, UNC other end     	  ) Four digits
	SMMM	Metric                                 	  )

ALL CODES:

All codes (Part Numbers) have eight letters/ figures. Shank lengths, material specification and finish are all standard.