Bottom Centering Washer
- Bottom centering washer locates a pin / stud central in its hole
- Recessed / spigot form centres the fitting and spreads load
- Hot-dip galvanized to ASTM A-153
- For insulator studs and pin bases
- Keeps the stud square so the insulator stands true
- Used under line-post studs and pin bases
Technical Specifications
| Catalog | For Stud | OD (mm) | Recess (mm) | Thickness (mm) | Surface |
|---|---|---|---|---|---|
| RAX-BCW-58 | 5/8 in | 50 | 17 | 6 | HDG |
| RAX-BCW-34 | 3/4 in | 60 | 20 | 6 | HDG |
| Custom | Other sizes / configurations — send your conductor & structure spec | ||||
Application & Installation
Where it is used
The bottom centering washer sits under a line-post stud or pin base, with a recess or spigot that locates the stud central in its mounting hole. It centres and squares the fitting while spreading the bearing load, so the insulator above stands true and the stud is not loaded off-axis.
Installation sequence
- Select the washer for the stud size.
- Place it in the mounting hole, recess up.
- Seat the stud / pin base into the recess.
- Confirm the stud stands central and square.
- Tighten the stud nut against the washer.
Buyer’s Guide: Bottom Centering Washer
1. What a Bottom Centering Washer Does
A bottom centering washer is a bearing washer with a recess or raised spigot that locates a stud or pin base centrally in an oversize mounting hole. It both centres the fitting and spreads its load on the member — so the insulator above sits square and true.
2. Why Centering Matters
A line-post stud or pin loaded off-centre in its hole stands the insulator crooked and side-loads the stud. The centering recess holds the stud central, keeping the insulator vertical and the load axial.
3. Sizing to the Stud
Match the recess to the stud or pin base (5/8, 3/4 in) so it locates without slop. The washer OD and thickness give the bearing area for the cantilever load above.
4. Where It Is Used
Under line-post insulator studs and pin bases on steel arms and brackets, especially where the mounting hole is larger than the stud for assembly tolerance.
5. Galvanizing
Hot-dip galvanized to ASTM A-153 to match the stud and last in the joint outdoors.
6. Pairing
Used with line-post studs and crossarm pins. Order with the stud so the recess and stud size match.
