Contact Information

2550 S 27th Avenue
Broadview, IL 60155 

W6331 Bee Rd 
Watertown, WI 53098 

Lock Washers
3704 N Palmer Rd 
Milwaukee, WI 53212 

W6331 Bee Rd 
Watertown, WI 53098 

BosScrew® Fasteners

BosScrew™ Product Details (PDF)
BosScrew™ Info Sheet (PDF)

Request a Quote

The ITW Shakeproof BosScrew™ is the only screw for plastics that is designed not to loosen. Its unique thread form, designed with the patented WERCS® technology, works directly with the creeping aspect of plastic to interlock with the boss. The BosScrew™ utilizes standard head diameters and has the highest drive-to-strip ratio in the industry. This is the maximum performance fastener for most plastic applications. Time, temperature, and vibration only strengthen the joint.


  • Reduce parts in an assembly; no more inserts
  • Permits the design of shorter bosses-save material
  • No spring components needed in the joint
  • Savings in service issues due to fasteners

Available Features:

  • SEMS - add a washer under the head to span larger holes, protect fragile surfaces, and distribute load.

WERCS® Technology:

  • ITW’s new WERCS® Technology is revolutionizing the design and manufacturing of threaded products. This technology allows the formation of unique geometries on the thread. Utilizing the WERCS® Technology, ITW has developed a suite or platform of innovative threaded products — products designed to dramatically advance fastening performance, increase manufacturing efficiency and reduce overall installed cost.

bos figure 1

bos figure 2

boscrew hole size info 1

boscrew hole size info 3

Typical Mean Pilot Hole
Screw Size Inches (in.) Millimeters (mm)
#4 0.090 2.30
M3 0,093 2.37
#6 0.122 3.10
M3.5 0.122 3.10
#8 0.132 3.36
#10 0.154 3.92
M4 0.132 3.50
M5 0.154 3.90
M5.7 0.170 4.32
M6 0.186 4.80
1/4 0.210 5.33
M6.3 0.209 5.31
M8 0.248 6.30
5/16 0.265 6.73
3/8 0.286 7.27

* Approved recommendations with Acetal Nylon ABS and PBT or equivilant materials