Don-Jo BB74545 Full Mortise Ba...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$31.56
$27.71
Don-Jo BB74545 Full Mortise Ball Bearing Hinge 4-1/2" x 4-1/2" Steel, Square Corner, 5-Knuckle

Don-Jo BB74545 Full Mortise Ball Bearing Hinge 4-1/2" x 4-1/2" Steel, Square Corner, 5-Knuckle

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Model: NRPBB74545-633
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Don-Jo BB74545 Full Mortise Ball Bearing Hinge 4-1/2" x 4-1/2" Steel, Square Corner, 5-Knuckle

The Don-Jo BB74545 is a full mortise ball bearing hinge measuring 4-1/2" x 4-1/2" and constructed from durable steel, engineered for medium weight commercial doors with average frequency use. Featuring a 5-knuckle design with square corners and a 0.134 gauge steel body, this hinge meets ANSI A8112 template standards and is available in seven finishes to suit a wide range of commercial door applications. A non-removable pin (NRP) option is also available — specify NRP as a prefix when ordering.

Key Features

  • Full Mortise Design: Engineered for full mortise installation, providing a clean, flush fit on commercial door and frame applications.
  • Hinge Size: 4-1/2" x 4-1/2" dimensions suitable for medium weight doors in standard commercial settings.
  • Steel Construction: 0.134 gauge steel material delivers reliable strength and long-term durability for standard duty commercial use.
  • Ball Bearing Operation: Smooth ball bearing action reduces friction and wear, supporting consistent performance over average frequency use cycles.
  • 5-Knuckle Configuration: Five-knuckle design provides enhanced stability and even load distribution across the hinge barrel.
  • Square Corner Style: Square corner profile ensures compatibility with standard commercial door and frame preparations.
  • ANSI A8112 Template Compliance: Manufactured to ANSI A8112 template standards for straightforward, code-compliant installation.
  • Multiple Finish Options: Available in finishes 600, 632, 633, 639, 640, 651, and 652 to coordinate with a variety of door hardware specifications.
  • Non-Removable Pin Option: NRP (non-removable pin) variant available for added security — specify NRP as a prefix when ordering.

Certifications & Compliance

  • ANSI A8112 Template Compliant
  • Standard Duty — Commercial Grade

Technical Specifications

  • Subcategory: Hinges
  • Product Group: Door Hinges and Pivots
  • Product Subgroup: Full Mortise Hinges
  • Product Type: Full Mortise Hinges
  • Commercial/Residential: Commercial
  • Corner Style: Square corners
  • Duty Level: Standard Duty
  • Knuckles: 5
  • Product Size: 4.5" x 4.5"
  • Product Category: Door Hinges and Pivots
  • Department: Door Hardware

Typical Applications

  • Commercial Office Buildings
  • Educational Facilities
  • Healthcare Institutions
  • Retail Establishments
  • Industrial and Warehouse Facilities
  • Multi-Tenant Residential Properties
  • Government and Municipal Buildings

Why Don-Jo BB74545?

Don-Jo full mortise ball bearing hinges are built to ANSI A8112 template standards using 0.134 gauge steel construction, delivering dependable standard duty performance for commercial door applications. The BB74545's 5-knuckle ball bearing design and broad selection of seven available finishes make it a versatile, professional-grade solution for medium weight commercial doors requiring consistent, low-maintenance operation.

Manufacturer Resources

DON-JO Hinges

Product Specs

Subcategory:
Hinges
Product Group:
Door Hinges and Pivots
Product Subgroup:
Full Mortise Hinges
Product Type:
Full Mortise Hinges
Bearing Type:
Ball Bearing
Commercial/Residential:
Commercial
Corner Style:
Square corners
Duty Level:
Standard Duty
Knuckles:
5
Product Model:
BB74545
Product Size:
4.5" x 4.5"
Product Category:
Door Hinges and Pivots
Product Substrate:
Steel
Department:
Door Hardware

Don-Jo NRPBB74545-633 – Frequently Asked Questions

1) Will the Don-Jo BB74545 hinge fit a standard commercial door and frame prep?
The BB74545 is a 4-1/2 x 4-1/2 inch full mortise hinge with square corners, built to the ANSI A8112 template. That means the leaf size and screw hole pattern match the standard 4-1/2 inch square corner mortise cutout found in most hollow metal frames and commercial doors, so it drops into an existing prep without rework. If your door or frame has radius (rounded) corner pockets, this square corner leaf is the wrong profile and you need a radius corner hinge instead.
2) Is a Don-Jo BB74545 ball bearing hinge heavy enough for a solid core door with a closer on it?
The BB74545 is rated standard duty for medium weight commercial doors at average frequency use, so it suits offices, classrooms, retail back-of-house, and multi-tenant residential openings. A heavy door on a closer in a high-traffic entry is past what a standard duty hinge is meant to carry. For that, step up to a heavy weight hinge such as the McKinney TCA3386, also a 4-1/2 by 4-1/2 inch square corner 5-knuckle full mortise hinge but heavy duty rated.
3) What is the NRP option on the Don-Jo BB74545 and when do I need it?
NRP stands for non-removable pin. Order it by specifying NRP as a prefix, and every one of the seven finishes is available either way. You need NRP any time the hinge barrel is on the outside, or unsecured, side of the opening: exterior out-swing doors, stairwell and tenant doors, storage rooms. Without it the pin can be driven out and the door lifted off, defeating the lock entirely. On an in-swing door where the knuckles sit inside the secured space, the standard pin is fine.
4) Ball bearing or plain bearing hinge, which do I need?
Bearings matter once weight and traffic go up. The Don-Jo BB74545 uses ball bearings between the knuckles, which carry the door load with much less friction and knuckle wear than a plain bearing hinge, so it is the right pick for doors on closers or doors that cycle all day. A plain bearing hinge such as the Hager 1279 is a medium duty commercial option for lighter, lower-traffic interior openings, and the Hager 1541 is the residential plain bearing equivalent. Put plain bearing on a heavy door with a closer and the knuckles will wear and the door will start to sag.
5) My door hits the trim when it opens, will a 4-1/2 x 4-1/2 hinge fix that?
No. The BB74545 is a standard 4-1/2 by 4-1/2 inch butt hinge, its leaf width sets the door back only far enough to clear a normal frame face. To swing a door clear of deep casing or projecting trim you need a wide throw hinge, where the leaves are wider than they are tall, like the Hager WTBB1168 at 4-1/2 by 6 inches, heavy weight with 5 knuckles. If instead you need the full door opening width clear for wheelchair passage, that is a swing clear hinge such as the BEST CB248 for square edge doors.
6) Can I run power through the BB74545 for an electric strike or maglock?
No. The BB74545 is a plain mechanical hinge with no wire path through the barrel. To carry power from the frame into the door for an electrified lock, request-to-exit device, or door position switch, you need an electric through-wire hinge. The ACSI 5BB1 is that hinge in the same 4-1/2 by 4-1/2 inch 5-knuckle ball bearing full mortise format, with a concealed electric through-wire, 4 wire at 28 gauge. Typical practice is one through-wire hinge per door with the remaining hinges standard, so the BB74545 still covers the other two positions.
7) The door is heavier than standard duty - what hinge should be used instead of the BB74545?
The BB74545 is a standard duty hinge. For a heavier door in the same 4-1/2" x 4-1/2" square corner 5 knuckle format, the McKinney TCA3386 is a heavy weight version of the same footprint. The Stanley Security CB199 is a heavy weight full mortise concealed bearing hinge, and the BEST CB223 is a heavy weight concealed bearing hinge with pivot reinforcing for beveled edge doors. Confirm the door edge profile before choosing between them - the CB223 is cut for a beveled edge, and the BEST FBB212 is a pivot reinforced ball bearing hinge for square edge doors.
8) Can a swing clear hinge be substituted for the Don-Jo BB74545?
No - a swing clear hinge is a different opening solution, not a drop-in for the BB74545. The BEST CB248 is a steel full mortise concealed bearing swing clear hinge for square edge doors, and the Hager 1260 is a full mortise swing clear hinge with a 5-knuckle plain bearing design. Swing clear geometry carries the door out of the opening so the full clear width is available, which is why they get specified on ADA and healthcare gurney routes. The BB74545 is a conventional full mortise hinge and leaves the door thickness in the opening, so swapping one for the other changes the clear width of the door.
9) Which hinge should be used instead of the BB74545 when the door has to clear a deep trim or wall projection?
The BB74545 is a 4-1/2" x 4-1/2" hinge, so the leaf projection is fixed by that square size. When the door has to swing past deep trim or an obstruction, a wide throw hinge is the substitution: the Hager WTBB1168 is a 4-1/2" x 6" full mortise ball bearing wide throw hinge, heavy weight, with 5 knuckles. The extra leaf width throws the door further off the frame. Note the frame leaf prep is the same 4-1/2" height, but the door swings on a wider arc than the BB74545 provides.
10) For a stairwell or exterior out-swinging door, is the BB74545 the right choice against the alternatives?
For an out-swinging door where the hinge pin is exposed on the unsecured side, the BB74545 is ordered with the NRP non-removable pin option, specified as an NRP prefix, in any of its finishes. Among the alternatives, the BEST 1900R is a full mortise concealed bearing standard weight hinge supplied with a removable pin, so it addresses a different concern. Where the leaf must also resist a heavier door on that exterior opening, the McKinney TCA3386 is the heavy weight square corner 5 knuckle hinge in the same 4-1/2" by 4-1/2" size.
11) How many BB74545 hinges do I need per door?
Plan three 4-1/2 inch hinges for a standard 7-foot commercial door, and four for doors taller than 7 feet 5 inches, which is the normal trade rule for full mortise butt hinges. The BB74545 is sold and finished per hinge, so order the count for the opening. Hinges are non-handed in the sense that the same 4-1/2 by 4-1/2 square corner leaf works left or right hand; the pin simply flips with the door swing.
12) What finishes does the Don-Jo BB74545 hinge come in, and which one matches painted hollow metal?
Eight finishes: 600 primed for painting, 622 matte black, 632 bright brass, 633 satin brass, 639 satin bronze, 640 dark satin bronze, 651 bright chrome, and 652 satin chrome. For painted hollow metal frames, 600 primed is the one to order, it takes finish paint directly so the hinge disappears into the frame color. If you are matching existing satin chrome or brushed nickel-look lever hardware, 652 is the standard commercial pairing.
13) Can I use the BB74545 to standardize hinges across a whole building?
Yes, and that is what it is built for. It is a commercial 4-1/2 by 4-1/2 inch square corner full mortise hinge on the ANSI A8112 template, so it interchanges across any opening in the building already prepped to that standard, offices, classrooms, patient rooms, corridors, back-of-house. Pick one finish, then order standard pin for interior in-swing openings and NRP for exterior and secured-side doors. Openings needing a swing clear leaf for ADA clearance or a wide throw hinge to clear deep trim are the exceptions, and those need a different hinge type.
14) Will steel hinges hold up in an exterior or wet location?
The BB74545 is a steel hinge with a 0.134 gauge body, which is right for interior commercial openings and protected exteriors. In a coastal, pool, kitchen, or washdown environment, steel will eventually corrode at the knuckles no matter the plating, and you want a stainless hinge instead. The BEST CB223 is a stainless steel concealed bearing heavy weight pivot reinforced hinge for beveled edge doors, and the Hager 1541 is a stainless option on the residential side.
15) Is the McKinney TCA2314 a direct swap for the Don-Jo BB74545?
Dimensionally they line up. The McKinney TCA2314 and TCA2317 are both square corner, 5 knuckle, 4-1/2 by 4-1/2 inch full mortise hinges at standard duty, the same size, corner style, knuckle count, and duty class as the BB74545, so either drops into the same mortise pocket. Match your finish and confirm whether the opening needs a non-removable pin, which the Don-Jo offers as an NRP prefix on any finish.
16) Is there a simpler full mortise hinge than the Don-Jo BB74545 for a low traffic door?
The BB74545 is a ball bearing hinge. Where bearings are not needed, the Hager 1279 is a full mortise plain bearing commercial hinge with 5 knuckles in medium duty, and the Hager 1541 is a full mortise plain bearing residential hinge with stainless steel construction and a 5 knuckle design. Both trade the ball bearing action for a plain bearing barrel. The BB74545 itself is a commercial hinge, so on an opening being specified as commercial the 1279 is the closer plain bearing counterpart of the two.
17) I need a stainless steel hinge rather than the steel BB74545 - what are the options?
The BB74545 is built in steel. In stainless steel, the BEST CB223 is a stainless steel concealed bearing heavy weight pivot reinforced hinge for beveled edge doors, and the Hager 1541 is a full mortise plain bearing residential hinge with stainless steel construction and a 5 knuckle design. The CB223 is heavy duty and cut for a beveled edge; the 1541 is a plain bearing residential hinge. Neither is a like-for-like swap for a steel standard duty commercial ball bearing hinge, so match the one whose duty level and bearing type suit the opening.
18) What is the difference between a ball bearing hinge and a concealed bearing hinge?
Both reduce friction, the difference is whether you see the bearing. The Don-Jo BB74545 has visible ball bearings stacked between its five knuckles, the traditional commercial look. A concealed bearing hinge hides the bearing inside the barrel for a smooth, uninterrupted knuckle line, which some architects specify for appearance. The BEST 1900R is a steel full mortise concealed bearing standard weight hinge with a removable pin, and the Stanley Security CB1960R is the same idea in a medium duty architectural hinge. Function on the door is comparable at similar duty levels; it is mostly an aesthetic and spec call.
How fast can I get the Don-Jo NRPBB74545-633 delivered?
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Can I return it if it doesn’t work for me?
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Does the Don-Jo NRPBB74545-633 come with a warranty?
Absolutely. The Don-Jo NRPBB74545-633 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Don-Jo NRPBB74545-633?
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