The Bottom Centering Washer is a precision-engineered component for utility pole applications, used with crossarm pins on wooden crossarms. It centers the pin shank within previously drilled holes (such as 1-5/8 inch diameter) and provides a firm bearing surface for secure fastening. This washer is critical in retrofitting scenarios where existing holes need adaptation for smaller diameter pins, ensuring proper installation and alignment in overhead power line systems.
Constructed from steel or ductile iron per American Society for Testing and Materials (ASTM) A-536, the washer is hot-dip galvanized to meet ASTM Specification A153, providing resistance to corrosion and environmental factors. This treatment makes it suitable for long-term outdoor use in utility infrastructure.
The washer maintains structural integrity by preventing pin movement and ensuring uniform load distribution across the mounting surface. It facilitates quick retrofitting of crossarm holes, accommodating pin diameters such as 3/4 inch and 5/8 inch, while reducing stress on wooden components. The design promotes consistent alignment during installation, essential for reliable performance of transmission and distribution lines.
Specifications include an outside diameter of approximately 2-3/4 inches, flange diameter of 1-1/2 inches, and center hole size of 13/16 inches to fit standard pin shanks. Dimensions measure 2.72 inches in length and width, with 0.75 inches height and 0.38 pounds weight.
Bottom Centering Washers: Ensuring Precision and Durability for Industrial Applications
Pole line hardware manufacturer, RaxPower, specializes in producing a wide range of power line solutions, including the Bottom Centering Washer. Established in 2003 in Hebei Province, China, and with over 21 years of manufacturing expertise, our Bottom Centering Washers are engineered to combine precision and durability, offering optimal fastening solutions for industrial applications.
Utilizing advanced hot forging technology from our 17,000 square meters of production facilities, each washer achieves greater strength and accurate sizing, ensuring reliable performance and secure alignment to prevent wobbling in transmission lines.
RaxPower’s commitment to quality is demonstrated through rigorous load testing, multi-stage quality control, and compliance with international standards like ISO and IEC, with galvanization processes that provide corrosion resistance. These washers are ideal for demanding environments in power transmission, construction, and heavy machinery, supported by our innovative approach and cost-effectiveness.
GET A PRELIMINARY ESTIMATE. SEND US YOUR SPECIFICATIONS.
| Parameter | Value |
|---|---|
| Outside Diameter | 2-3/4 inches |
| Flange Diameter | 1-1/2 inches |
| Center Hole Diameter | 13/16 inches |
| Compatible Pin Diameters | 3/4 inch, 5/8 inch |
| Retrofitting Hole Size | 1-5/8 inches |
| Material | Ductile Iron (ASTM A-536) |
| Coating | Hot-dip galvanized (ASTM A153) |
| Length | 2.72 inches |
| Width | 2.72 inches |
| Height | 0.75 inches |
| Weight | 0.38 pounds |
Frequently Asked Questions (FAQS)
What is a bottom centering washer and what is its primary function?
A bottom centering washer, also called a Pin Hole Adapter, is a specialized hardware component used in utility pole applications. It centers the pin shank in the crossarm hole and provides a firm bearing surface for the nut when installing steel pins onto wooden crossarms. This ensures proper positioning, prevents movement during installation, and enables retrofitting of previously drilled holes to accommodate smaller diameter pins.
What materials and coating are used in construction?
Bottom centering washers are cast from steel or made from ductile iron per ASTM A-536. They are hot-dip galvanized per ISO 1461 with a mean coating thickness exceeding 85 microns, providing superior corrosion resistance and durability for outdoor utility environments and meeting rigorous grid infrastructure standards.
What are the standard dimensions and weight specifications?
Standard dimensions include an outside diameter of 2-3/4 inches (approximately 2.720 inches), an outside diameter flange of 1-1/2 inches, a center hole of 13/16 inches, and a height of 0.750 inches. The unit weight is approximately 0.38 pounds.
What pin sizes and crossarm hole dimensions are compatible with these washers?
These washers are precision-engineered for use with 3/4-inch and 5/8-inch diameter shank steel pins. They are designed for crossarm holes previously drilled to 1-5/8 inches or 1-1/2 inches, allowing smaller diameter pins to be securely installed in existing infrastructure.
How is a bottom centering washer installed?
Place the washer in the bottom of the pre-drilled pin hole on the wooden crossarm. Insert the steel pin through the washer's center hole, which will center the pin shank and provide a firm bearing surface for the nut, enabling secure and aligned fastening.
Why are these washers cost-effective for bulk procurement in large-scale projects?
Manufactured from high-quality materials with standardized dimensions, these washers offer consistent quality and reliable performance. Their durability and corrosion resistance reduce long-term maintenance and replacement costs, making them economical for large-scale utility infrastructure projects.
Get A Quick Quotation Today
