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Five Knuckle Plain Bearing
Five Knuckle Plain Bearing commercial hinges are a cost-effective, full-mortise hinge option for standard-weight doors, where usage is light to moderate and smooth operation remains important. Shop National Lock Supply for Five Knuckle Plain Bearing hinges in common commercial sizes and materials to match typical wood or hollow-metal door openings.
Frequently Asked Questions
What are Five Knuckle Plain Bearing hinges?
They’re commercial-style butt hinges with five knuckles and a plain bearing (non–anti-friction) construction—commonly used on standard-duty doors where high-cycle performance isn’t the primary requirement.
What does “plain bearing” mean?
In BHMA terminology, plain bearing (non-bearing) means there is no bearing material between the moving parts of the hinge (unlike ball bearing or other anti-friction designs).
What is a full mortise hinge?
A full mortise hinge has one leaf mortised into the door edge and the other mortised into the frame so the hinge sits flush when the door is closed.
When should I choose plain bearing vs. ball bearing?
Choose plain bearing for low-frequency or lighter-duty openings; choose ball bearing / anti-friction for high-traffic doors and doors where long-term smoothness under heavier loads is a priority.
Are Five Knuckle Plain Bearing hinges recommended for doors with closers?
Many product lines note that plain bearing hinges are recommended for low-frequency usage and may be not recommended for use with a door closer, so for closer-equipped doors it’s common to step up to an anti-friction option.
What sizes are common in this category?
On this category page, common sizes include 3-1/2" x 3-1/2", 4-1/2" x 4", and 4-1/2" x 4-1/2" (depending on the series and door/frame prep).
What materials are available?
Material options vary by series, but listings in this category commonly include steel and stainless steel, and some lines also specify options like brass, 1040 steel, or 304 stainless depending on model.
Do these hinges follow an industry standard?
Commercial butts and hinges are commonly specified to ANSI/BHMA A156.1, which covers dimensional/material requirements and performance testing such as cycle and wear tests.
Which brands appear in this Five Knuckle Plain Bearing selection?
This category includes options from brands such as Hager, IVES, and McKinney, among others.
Why buy Five Knuckle Plain Bearing hinges from National Lock Supply?
You can quickly match door requirements with in-stock, commercial-focused options in common sizes and materials—plus multiple brand/price tiers—so you’re not forced into a one-series-fits-all hinge choice.