The figure displays the item number, model number, specifications, and name of different varieties of screws. They are given as follows: item 14, D400F1, hash 10-24 UNC cross 0.38 LG, pan head screw; item 19, D400F6, 5 over 6-18 UNC cross 0.18 LG, pan head screw; item 15, D400F2, hash 1 over 4-20 UNC cross 0.88 LG, truss head screw; item 16, D400F3, hash 10-24 UNC cross 1.62 LG, binder head screw; item 17, D400F4, hash 10-24 UNC cross 3.75 LG, binder head screw; item 18, D400F3, hash 1 over 4-24 UNF cross 1.25 LG, and item 20, D400F7, hash 8-32 UNC cross 0.25 LG, flat head screw. The cross-sectional view of item number 13 displays a circle of diameter 0.128 and a rectangular block labeled cut to fit. The section is made up of steel material with the model number labeled D400C2. The internal structure of the screw with its dimensions is illustrated below. The structure comprises a chamfered portion at one end (tail), two steps at the other (head), and a shaft shaped in the middle region. The tail end of the screw is chamfered to a dimension of 0.03 cross 45 degrees. Hence the diameter and thickness of the chamfered portion measure 0.62 and 0.12, respectively. The diameter of the shaft region is 0.38. The length of the two-stepped portion at the head surface is 0.19 and 0.38, respectively. The part of the screw that extends from the underside of the head to the tip measures 1.00. Similarly, the medium knurl is the region that extends beneath the head to a thickness of 0.32. The figure labeled item number 10 displays the thumb knob. The structure shows four circles with a common center. The diameter of the three circles are specified as 1.00, 0.88 cross 0.12 deep counterbore, and has 1 over 4 -24 UNF through. The thumb knob is made up of brass.