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Quick Verdict

Order the 4900 heavy duty deadlatch for any high traffic storefront where the latch is cycled all day: it retrofits existing 4510 and discontinued 4700 preparations, so the upgrade needs no new stile cutout. Order the 4510 series standard duty deadlatch when the door sees moderate traffic, when you need the 7/8 in. backset (the 4900 does not come in it), or when the existing faceplate is radius (4511) or bevel (4512). Both accept a 1 in. long, 1-5/32 in. diameter mortise cylinder with MS cam, both offer key-controlled bolt holdback, and both take the same 4560, 4565, 4590 and 4591 handles. If the door needs card access, the 4300 Steel Hawk drops into the same prep.

What actually changes between the 4900 heavy duty and the 4500 standard duty?

Both families work the same way: key, handle or paddle retracts the spring-loaded latchbolt, and a reverse key turn with the bolt pushed in holds it retracted for free swinging business hours. The difference is the body and the options around it.

Model	Duty	Backsets offered	Faceplate	Case width x height	Typical use	Order
4510	Standard	7/8, 31/32, 1-1/8, 1-1/2 in.	Flat	1 x 5-13/16 in.	Moderate traffic retail, offices, clinics	Adams Rite 4510 standard duty deadlatch
4511	Standard	1-1/8 or 1-1/2 in.	Radius	1 x 5-13/16 in.	Radius edge doors	Deadlatch category
4512	Standard	1-1/2 in.	Bevel	1 x 5-13/16 in.	Beveled edge doors	Deadlatch category
4530	Standard (retrofit)	7/8, 31/32, 1-1/8 in. only	Flat, 1-1/4 x 7-13/32 in.	1 x 5-13/16 in.	Old MS1850 and discontinued 4250 preps	Deadlatch category
4900	Heavy	31/32, 1-1/8, 1-1/2 in.	Flat (standard)	7/8 x 5-13/16 in.	High traffic entrances, retrofit of 4510 and 4700 preps	Adams Rite 4900 heavy duty deadlatch
4300 Steel Hawk	Electrified	31/32, 1-1/8, 1-1/2 in. (by suffix)	Flat and radius both supplied	15/16 x 5-13/16 in.	Card reader or keypad entry	Adams Rite 4300-30 Steel Hawk, 1-1/8 in. backset

Three facts drive the decision. First, the 4900 requires a 1-3/4 in. minimum door thickness. Second, the 4900 has no 7/8 in. backset, so a door already cut for 7/8 in. stays in the 4510 or 4530 family. Third, both the 4900 and the 4510 series are interchangeable, without stile modification, with an MS1850S deadlock of the same backset and faceplate shape. Adams Rite notes the 4510 does not provide the same maximum security level as the MS deadlock, so if the job is really about after-hours security rather than traffic control, read the MS1850 vs MS1890 deadbolt buying guide before you choose a latch at all.

Price gap is small: the 4900 runs about $96 at NLS and the 4510 about $71 at NLS, both less cylinder. Both are stocked in the deadlatch category.

How do you read backset and faceplate off the existing latch?

Pull the latch and measure the latch, not the door. Backset is faceplate to cylinder hole centerline, and the catalog values are exact: 7/8 in. (22.2 mm), 31/32 in. (24.6 mm), 1-1/8 in. (28.6 mm) or 1-1/2 in. (38.1 mm). 7/8 in. and 31/32 in. are 3/32 in. apart, so read the stamping on the case or use calipers rather than a tape.

Then classify the faceplate:

1. Flat: square edge door. 4510 or 4900.
2. Radius: the faceplate is curved to follow a rounded door edge. 4511.
3. Bevel: angled faceplate for a beveled edge. 4512.
4. Long flat 1-1/4 x 7-13/32 in.: that is the old MS1850 or 4250 cutout. Order the 4530 retrofit, which fits that prep without alteration.

The 4300 Steel Hawk ships with both flat and radius faceplates, and the flat one field adjusts for a left or right bevel. Last check: every latch here takes a 1 in. long mortise cylinder with MS cam, such as the Adams Rite 4036, or a 4066 thumbturn. A standard cam will not throw the latch. Order body and cylinder as separate lines.

Which handle or paddle fits, and how is handing chosen?

Every handle and paddle below fits the 4300, 4500 and 4900 series through an activator cam plug that seats in the latch's cylinder hole, held by the cylinder set screw. For the paddle vs lever argument on aesthetics and ADA, see the storefront trim comparison of paddle vs lever; this section covers part numbers and handing only.

Trim	Action	Handing options	Finishes (from model codes)	Order
4560 lever	Natural downward push, ADA compliant lever	5 = LH or LHR, 6 = RH or RHR, field reversible by flipping the cam	630, 313	Adams Rite 4560 deadlatch lever handle
4565 turn	Short thumbturn for doors operated infrequently	5 = LH or LHR, 6 = RH or RHR, field reversible	630, 313	Adams Rite accessories
4590 flat paddle	Push or pull in the direction of swing	-01 pull left, -02 push left, -03 pull right, -04 push right	628, 313, 335	Adams Rite accessories
4591 curved paddle	Push or pull, curved profile	-01 pull left, -02 push left, -04 push right, plus door thickness code	628, 313, 335	Adams Rite accessories

The 4560 lever uses a sloping 1-3/8 x 4 in. escutcheon with a 1/4 in. square heat-treated spindle, and its concave thumb rest keeps knuckles off the jamb on a short backset. It is not designed as a door pull: the door still needs a separate pull.

Paddles are where wrong orders happen. Adams Rite names them by what the hand does, not by door hand, and each part covers two positions:

• Push to right (-04): outside of a RH door or inside of a LHR door.
• Push to left (-02): outside of a LH door or inside of a RHR door.
• Pull to left (-01): outside of a LHR door or inside of a RH door.
• Pull to right (-03): outside of a RHR door or inside of a LH door.

The 4591 curved paddle adds a door thickness code: 00 for 1-3/4 in., 01 for 1-13/16 to 2 in., 02 for 2-1/4 to 2-1/2 in. One more trap: the 4590-11, -12 and -13 listings are titled for MS+1890 and 2190 series locks. The standard 4590 cam plug is not for use with MS+1890 or 2190/2290 hardware, so confirm the lock family before ordering a paddle by suffix alone. If the door hand is unclear, determine it from the outside (secure side) of the door before you pick a suffix.

When does the 4300 Steel Hawk electrified deadlatch replace a 4900?

When the storefront needs credential entry without frame work, the 4300 Steel Hawk is the drop-in: interchangeable without stile modification with MS deadlocks and the 4500 and 4900 deadlatches.

What you get: fail secure operation only, 12, 16 or 24 VDC, continuous duty rating, a quick connect plug-in connector, an optional form C latch status monitor, a stainless steel latchbolt with 5/8 in. throw and an all-metal auxiliary bolt that deadlocks the latchbolt against loiding. The inside handle or paddle always retracts the latch, so free egress is mechanical. Entry is by keyed mortise cylinder or by the access control device. Backset is set by suffix: -20 is 31/32 in., -30 is 1-1/8 in., -40 is 1-1/2 in. Each version is about $347 at NLS, less cylinder.

Plan a power transfer, a power supply and a strike. If you would rather electrify the frame side and keep the mechanical latch, compare the Adams Rite 7100 vs 7400 electric strike options first. Electrified hardware on an egress door is subject to the authority having jurisdiction (AHJ) and local code, and the wiring belongs to a qualified technician. Order the 4300-30 Steel Hawk linked in the table above, or its -20 and -40 siblings, once the backset is confirmed.

Storefront door won't latch: deadlatch, strike or door?

Before ordering a new latch, work through the opening in this order:

1. Holdback engaged. The most common "broken" deadlatch was left in holdback with the reverse key turn. Turn the key forward; if the bolt springs out, nothing is broken.
2. Closer. If the door stops short or bounces off the stop, the latch never reaches the strike. Adjust latch speed on the closer before blaming the lock.
3. Strike alignment. Sagging pivots or a shifted frame move the strike pocket; look for fresh wear marks. Shims, spacers and strikes are covered in the storefront lock parts breakdown.
4. Cylinder cam. A wrong cam, or a cylinder screwed in too far, binds the latch. Back it out and test with the handle.
5. Auxiliary bolt and latchbolt wear. If the latchbolt is visibly worn or the latch retracts by itself, replace the body. On a door that wore out a standard duty latch, step up to the 4900.

If steps 1 to 4 pass and the latch body is the fault, the order is a 4900 or a 4510 series latch of the same backset and faceplate, from the deadlatch category.

What goes on the ordering checklist?

• Latch family: 4900, 4510/4511/4512, 4530 retrofit or 4300 electrified.
• Backset and faceplate, read off the old latch.
• Door thickness: 1-3/4 in. minimum for 4900 and 4300; thickness code for the 4591.
• Cylinder with MS cam; inside thumbturn or handle.
• Inside trim with push/pull and left/right suffix, plus finish.
• For the 4300: voltage, latch monitor, power path and strike.

Stock items ship same day on orders placed by 3 p.m. ET.

Common mistakes

1. Ordering a 4900 for a door cut for 7/8 in. backset. The 4900 is not offered in 7/8 in.
2. Measuring backset with a tape and confusing 7/8 in. with 31/32 in.
3. Ordering a cylinder with a standard cam instead of an MS cam.
4. Picking a paddle by door hand instead of by push or pull and direction, then receiving the mirror image.
5. Using a standard 4590 paddle on an MS+1890 or 2190 lock: the cam plug is not for those locks.

FAQ

What is the difference between the Adams Rite 4900 and 4510? The 4900 is the heavy duty deadlatch with a 7/8 in. wide case and backsets of 31/32, 1-1/8 and 1-1/2 in. The 4510 is standard duty with a 1 in. wide case and adds the 7/8 in. backset. The 4900 retrofits existing 4510 preparations without stile modification.

What is the Adams Rite 4591? The 4591 is the curved deadlatch paddle for 4300, 4500 and 4900 series deadlatches. It comes as push or pull, left or right, with a door thickness code from 1-3/4 in. up to 2-1/2 in. The cam plug for those deadlatches is included.

Which Adams Rite deadlatch handle should I use? Use the 4560 lever for daily traffic where an ADA compliant lever is wanted, or the 4565 turn where the latch is operated infrequently. Both are field reversible between LH/LHR and RH/RHR. Paddles (4590 flat, 4591 curved) suit doors where users push or pull in the direction of swing.

Is the Adams Rite 4300 fail safe or fail secure? The 4300 Steel Hawk is fail secure only, on 12, 16 or 24 VDC, rated for continuous duty. The inside handle or paddle always retracts the latch mechanically. Installation on egress doors is subject to the AHJ and local code.

Next step

Confirm backset and faceplate, then order the body and trim together: browse the Adams Rite accessories for cylinders and handles, or go straight to the 4591-02 curved paddle, push to left or the 4590-04 flat paddle, push to right. Orders of $450 and up ship ground free. For multi-door storefront packages send the schedule to the quote desk, and agencies can submit a government PO.