Screws For Plastic And Other Low Density Materials

The High Performance Fastener For Plastics, Particle Board, Masonite And Wood

The Hi-Lo fastener, with its unique thread form, improves fastener performance in a broad range of low density materials such as plastics,wood, masonite and particle board. This fastener is designed with a double lead, consisting of a high and a low thread. The high thread is sharper than a conventional thread, having a 30° included angle. The low thread has the 60° included angle and a height that is 40% to 50% of the high thread height.

Reduced Cracking, Splitting And Boss Breakage

The superior performance of the Hi-Lo fastener increases product quality and decreases costs. The 30° included angle of the high thread form reduces radial or bursting pressure to one-half of that generated by the conventional 60° included angle thread form. Boss cracking in plastic is dramatically reduced and smaller diameter bosses can often be specified. In wood applications, even when driving close to the edge, splitting is greatly reduced due to this lower radial pressure.

tf16-1

Increased Pull-Out Strength

tf16-2

The Hi-Lo screw thread configuration has a smaller minor diameter than a conventional screw. The high threads make a deeper cut into the material between the threads. There is also a greater amount of material in contact with the high, sharp thread and the axial shear area is increased. All of this contributes to greater resistance to pullout and stronger fastening.

Lower Driving, Higher Stripping Torques

tf16-5

The 30° included angle of the high thread displaces less material when it is driven into plastic or wood and, therefore, requires lower driving torques. A greater amount of material remains between the high threads, increasing the stripping torque. Low driving torque and high stripping torque provide maximum protection against stripping problems.

Phillips Pan Head Dimensions In Inches

SCREW SIZE 2
3		 4 5 6 7
8		 10 11
12		 13 1/4
9/32
G HEAD
DIAMETER		 MAX.
MIN.		 .167
.155		 .193
.180		 .219
.205		 .254
.240		 .270
.258		 .322
.306		 .373
.357		 .425
.407		 .492
.473
H HEAD
HEIGHT		 MAX.
MIN.		 .062
.053		 .071
.062		 .080
.070		 .097
.087		 .097
.087		 .115
.105		 .133
.122		 .151
.139		 .175
.162
T PENETRATION
GAGING
DEPTH		 MAX.
MIN.		 .052
.034		 .061
.043		 .071
.053		 .072
.046		 .080
.055		 .097
.071		 .113
.089		 .124
.098		 .144
.118

Indented Hex Washer Head Dimensions In Inches

SCREW SIZE 2 3
4		 5
6		 7
8		 10
11		 12
13		 1/4
9/32
5/16
L WASHER
DIAMETER		 MAX.
MIN.		 .167
.154		 .177
.163		 .260
.240		 .328
.302		 .348
.322		 .432
.396		 .520
.480
G ACROSS
CORNERS		 MIN. 0.134 0.134 0.202 0.272 0.272 0.34 0.409
F ACROSS
FLATS		 MAX.
MIN.		 .125
.120		 .125
.120		 .187
.181		 .250
.244		 .250
.244		 .312
.305		 .375
.367
H HEAD
HEIGHT		 MAX.
MIN.		 .050
.040		 .055
.044		 .070
.058		 .093
.080		 .110
.096		 .155
.139		 .190
.172
M WASHER
THICKNESS		 MAX.
MIN.		 .016
.010		 .016
.010		 .025
.015		 .025
.015		 .031
.019		 .039
.022		 .050
.030

tf16-6

Hi-Lo Fasteners Dimensions In Inches

SCREW SIZE HIGH THREAD
DIA. (D)MAX.		 HIGH THREAD
DIA. (D) MIN.		 LOW THREAD
DIAMETER
(P)		 POINT
DIAMETER
(d)		 RECOMMENDED
PILOT HOLE
DIAMETER*
3-28 0.105 0.095 0.078 0.061 0.078
4-24 0.115 0.105 0.086 0.066 0.086
5-20 0.125 0.119 0.1 0.078 0.099
6-19 0.145 0.135 0.108 0.085 0.108
7-19 0.158 0.148 0.03 0.095 0.125
8-18 0.17 0.16 0.13 0.1 0.128
10-16 0.195 0.185 0.145 0.105 0.144
11-16 0.21 0.198 0.15 0.119 0.15
12-16 0.22 0.21 0.176 0.131 0.166
13-16 0.23 0.22 0.18 0.133 0.18
1/4-15 0.26 0.25 0.2 0.168 0.2
5/16-14 0.317 0.307 0.25 0.206 0.25
* These hole sizes are tentative and are provided as a guide only. Actual hole size could vary depending on type of plastic, boss diameter and length of thread engagement.