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Quick Verdict

Measure the pocket already cut in the frame and buy the strike that matches it; never recut a frame to suit a strike. A 4-7/8" x 1-1/4" square-corner pocket is the ANSI A115 prep on nearly every hollow metal frame: Schlage 10-025 (no box) where the frame has a factory mortar guard, 10-072 (with box) on wood frames and L9000 mortise locks, or Don-Jo ST-261 when a 13-gauge commodity plate is enough. A 2-3/4" x 1-1/8" pocket is the T-strike prep on wood jambs: Schlage 10-013 or 10-001, or Don-Jo TS-234. A 2-1/4" x 1-5/8" round-corner pocket takes the Schlage 10-027 full lip strike. Lip length is half the door thickness plus 1/4", rounded up to stock: 1-1/8" on a 1-3/4" door. Deadbolts get a no-lip box strike, Schlage 10-078 in the 4-7/8" prep or 10-079 in the 3-1/2" x 1-1/8" prep.

Which strike plate prep do I have: ANSI 4-7/8", T-strike 2-3/4", or full lip 2-1/4"?

The ANSI strike prep (ANSI/BHMA A115.1 for mortise locks, A115.2 for bored locks) is 4-7/8" high by 1-1/4" wide, square corners, two screw holes on the centerline. Hollow metal frames ship with it, reinforced and usually fitted with a mortar guard; commercial wood frames on spec jobs are routed to match. On the Don-Jo ST-261 standard ANSI strike the screw holes sit 4-1/8" center to center, which confirms an ANSI prep when the old plate is gone.

The T-strike prep is 2-3/4" by 1-1/8", square corners, screw holes about 2-1/8" apart (2.124" on the Don-Jo TS-234), the standard pocket in wood jambs and residential-grade openings. A Grade 1 cylindrical latch seats in either plate; the frame decides.

The full lip prep is 2-1/4" by 1-5/8" with a 1/4" radius round corner, cut with a router. The Schlage 10-027 full lip strike covers it with a 1-1/8" lip and no box; a square plate in a round pocket rocks and loosens its screws.

Which frames carry which prep is covered in the guide to commercial door frame types and hardware compatibility; aluminum storefront deadlatch strikes are a different family. The same 4-7/8" pocket takes an electric strike faceplate when the opening goes on access control, covered in the electric strike faceplates guide, ANSI vs ASA and the HES electric strike model guide; top and bottom strikes for panic hardware are ranked in the exit strike plates roundup.

Strike type	Prep (H x W)	Corner	Lip to center	Box	Typical frame / door	NLS examples
ANSI latch strike	4-7/8" x 1-1/4"	Square	7/8" to 2" (1-1/8" standard)	Optional	Hollow metal; commercial wood; 1-3/8" to 2-1/2" doors	Schlage 10-025 (no box; 1-3/8", 1-1/2"), 10-072 (box; 7/8", 1", 2"), Don-Jo ST-261 (13 ga), EST-158 (1-5/8")
T-strike	2-3/4" x 1-1/8"	Square	1-1/8" standard, 1-1/2"	Optional	Wood jambs; residential and light commercial	Schlage 10-013 118 and 112 (metal box), 10-001 118 (plastic C603-623 box), Don-Jo TS-234 (16 ga)
Full lip strike	2-1/4" x 1-5/8"	1/4" radius	1-1/8"	No	Router-cut wood jambs	Schlage 10-027
Deadbolt box strike, ANSI	4-7/8" x 1-1/4"	Square	None	Yes	ANSI-prepped hollow metal or wood; L400 mortise deadbolts	Schlage 10-078
Deadbolt box strike, small	3-1/2" x 1-1/8"	Square	None	Yes	Prep Schlage lists as ANSI 115.5; standard L400 strike	Schlage 10-079
Mortise curved lip strike	4-7/8" x 1-1/4" (A115.1, two cutouts)	Square	1-1/8", 2-3/8", 2-7/8" by door thickness	No	Sargent 7800 and 8200, 1-3/8" to 5" doors	Sargent 82-0109, 82-0115, 82-0117

How do I measure strike lip length, and which lip should I buy?

"Lip to center" is the number on every listing: the distance from the strike's centerline (the screw-hole line, also the latch-hole centerline) to the end of the lip. The lip ramps the latchbolt back into the door as it closes until it drops into the pocket. Too short and the latch hits the frame corner and eventually stops latching; too long still works but projects past the frame face and snags carts.

With the door closed against the stop, measure the rabbet, face of stop to the outer corner of the frame (the corner the lip has to wrap): 1-15/16" on a standard hollow metal frame for a 1-3/4" door. Locate the latch centerline from the stop: half the door thickness plus the door-to-stop gap, about 1/8" (more with kerf gasket), so 7/8" + 1/8" = 1" on a 1-3/4" door. Subtract: 1-15/16" minus 1" leaves 15/16" for the lip to cover. Add 1/8" to 3/16" so the lip wraps the corner instead of ending on it, and round up to the next stock lip; that is where the standard 1-1/8" comes from.

Shortcut for a standard frame with the door 1/8" off the stop: lip = half the door thickness + 1/4", rounded up. A 1-3/8" door gives 15/16", buy 1"; 1-3/4" gives 1-1/8"; 2-1/4" gives 1-3/8"; 2-1/2" gives 1-1/2". Sargent sizes its 7800 and 8200 curved lip strikes by door thickness rather than by frame, roughly half the door plus 3/8", so the 82-0109, 82-0115, and 82-0117 appear by door range in the chart. Price follows lip and box: the Don-Jo ST-261 runs about $6 at NLS, the Schlage 10-025 about $48, the 10-072 in 7/8" or 1" lip and the 10-078 deadbolt strike about $26, and the 10-072 in the 2" lip about $66.

Latch center to frame corner (measured)	Lip to buy	Where you meet it	Stock examples
Up to 3/4"	7/8"	1-3/8" doors in tight frames	Schlage 10-072 078
3/4" to 7/8"	1"	1-3/8" to 1-1/2" doors, standard rabbet	Schlage 10-072 100
7/8" to 1"	1-1/8"	1-3/4" door, standard stop, door 1/8" off stop	Schlage 10-013 118, 10-001 118, 10-027; Sargent 82-0109 (mortise, 1-3/8" to 1-1/2" doors)
1" to 1-1/4"	1-3/8"	2" to 2-1/4" doors; gasketed 1-3/4" doors	Schlage 10-025 138
1-1/4" to 1-3/8"	1-1/2"	2-1/2" doors; deep rabbets; applied stops	Schlage 10-025 112, 10-013 112; Don-Jo EST-115
1-3/8" to 1-1/2"	1-5/8"	Oversize rabbets on 2-1/2" doors	Don-Jo EST-158
1-3/4" to 1-7/8"	2"	Doors around 3" to 3-1/2"; setback frames	Schlage 10-072 200
2-1/8" to 2-3/4"	2-3/8" or 2-7/8" (curved, mortise)	3-3/8" to 5" acoustic, lead-lined, cooler doors on Sargent 8200	Sargent 82-0115, 82-0117

Latch strike vs deadbolt box strike vs mortise strike: what changes for a 1" throw deadbolt

A latch strike has a lip and one cutout for a spring latch that has to be ramped in. A deadbolt strike has no lip, because nothing rides over it: the bolt is thrown after the door is closed. What it needs is depth, which is why the ones worth buying come with a box.

The box (dust box, strike box) is the cup behind the plate that lines the pocket. A Grade 1 deadbolt throws 1", the bolt has to reach full throw to deliver the engagement the grade is tested at, and on many deadbolts the key will not return to the pull position until the stroke completes. Without a box the bolt lands on grout, on fiberglass in a wood frame, or on a pocket never cut deep enough: it stops short and the key turns hard.

Schlage covers the L400 mortise deadbolt family with two box strikes, no lip on either. The 10-078 is the one people search for by its dimensions, the 1-1/4" x 4-7/8" box strike deadbolt plate: it drops into the standard ANSI pocket of a hollow metal frame when an L400 deadbolt goes into a frame prepped for a full lockset strike. The 10-079 is the smaller 1-1/8" x 3-1/2" box strike Schlage lists as the standard L400 strike for the prep its listing calls ANSI 115.5, for frames prepped for a deadbolt from the factory.

Mortise lock strikes catch brand-switchers. The outline is the same 4-7/8" x 1-1/4" A115.1 pocket, but the plate carries two cutouts, latch and deadbolt, at the spacing of that manufacturer's lock body: a Sargent 8200 strike does not line up with a Schlage L9000 or Corbin Russwin ML2000 bolt, so when you change mortise brands the pocket stays and the plate changes. Schlage's L series plate is the 10-072 strike with box; Sargent's are the 82-01xx curved lip strikes above. Surface-mounted jimmy-proof deadlocks such as the Accentra (Yale) 197 1/4F lock into a surface strike, flat for outswinging doors, with no frame pocket to match.

Which strike fits my lock: Schlage ND, AL, L9000, and L400, Sargent 8200, Yale, Corbin Russwin, Falcon

For cylindrical locks the frame prep picks the strike. Grade 1 and Grade 2 cylindrical locks from Schlage, Sargent, Yale, Corbin Russwin, and Falcon all seat in an ANSI 4-7/8" latch strike or a 2-3/4" T-strike; what differs is the plate in the box and its lip, which is why the Don-Jo ST-261 (13 gauge steel, 0.688" x 1-1/4" latch hole) and TS-234 (16 gauge non-ferrous, 0.640" x 1.260" latch hole) work as universal replacements, one per prep. Mortise lines from every brand use the strike sold under the lock's own number.

• Schlage ND and AL: the 10-025 ANSI strike is the no-box plate for hollow metal, in 1-3/8" and 1-1/2" lips and finishes 626, 605, 606, 612, 613, 619, and 625 to match the lever. In wood jambs the 10-001 118 T-strike with its plastic C603-623 box is the listed strike for the A, AL, B250, CS210, H, S, and S200 series. What each line ships with is in the Schlage commercial lock series guide.

• Schlage L9000: 10-072 box strike, lip by measurement. L400 deadbolt: 10-078 in a 4-7/8" prep, 10-079 in the 3-1/2" prep.

• Sargent 7800 and 8200: 82-0109, 82-0115, or 82-0117 by door thickness. Those three cover 1-3/8" to 1-1/2" and 3-3/8" to 5" doors; for a standard 1-3/4" door the strike comes with the lock.

Pay for the OEM plate when the finish shows next to a 626 or 605 lever, when the lock's fire door listing names its strike, or when you need a lip the commodity lines do not stock; buy the ST-261 by the box for painted back-of-house frames.

Can a strike plate upgrade security? Screws, reinforcers, wrap plates, latch guards, and fire door limits

On a hollow metal frame the strike is not the weak point: the plate screws into a welded reinforcement and a heavier plate changes nothing. What fails is the gap where a pry bar or a card reaches the latch, a latch guard job covered in the anti-pry latch guard guide.

On a wood frame the strike does matter, because the two short screws in the box bite into 3/4" of jamb. Replace them with 3" screws that reach the stud; on a T-strike prep that alone moves the failure point to the door edge. Move to the 13-gauge ST-261 only if the jamb is already routed for it, since chiseling a 2-3/4" pocket out to 4-7/8" weakens the jamb more than the plate adds. Once the frame holds, the door edge splits next; a wrap-around plate reinforces it, sized in the wrap-around door plate sizing guide.

Fire doors set the ceiling. The strike is part of the listed latching assembly, so on a labeled opening you use the strike furnished with or listed for the lock, in the prep the frame came with; NFPA 80 limits field work on labeled frames to specific job-site preparations, and enlarging a strike pocket is not one of them. The annual inspection checks that latching hardware secures the door closed, so a lip too short to seat the latch is a written deficiency; the items are summarized in the NFPA 80 annual fire door inspection guide.

Common mistakes when ordering a commercial strike plate

1. Ordering by lock brand instead of frame prep. A Schlage lever does not need a Schlage strike; a 4-7/8" pocket needs a 4-7/8" plate.

2. Sizing the lip from door thickness alone. Kerf gasket, applied stops, and oversize rabbets each add reach; measure latch centerline to frame corner.

3. Buying a no-box 10-025 for a wood frame or a grouted frame with no mortar guard. The latch lands in insulation or mortar and never seats.

4. Putting a lipped latch strike behind a deadbolt. The cutout is the wrong shape and the bolt stops short of full throw; use the 10-078 or 10-079.

5. Swapping mortise brands and keeping the old strike. The deadbolt cutout misses; order the new lock's plate with the lock.

6. Matching finish by name. 626 satin chrome and 630 satin stainless read differently under fluorescent light; order the strike in the lever's BHMA code.

FAQ

What size is a standard commercial door strike plate?

4-7/8" high by 1-1/4" wide with square corners, the ANSI/BHMA A115 strike on hollow metal frames. Wood jambs commonly carry the 2-3/4" x 1-1/8" T-strike, and router-cut residential preps take the 2-1/4" x 1-5/8" round-corner full lip strike.

Which strike fits a 1-1/4" x 4-7/8" deadbolt box prep?

The Schlage 10-078 strike with box, no lip, listed for L400 series mortise deadbolts. The 10-079 is the same idea in 1-1/8" x 3-1/2" for the smaller deadbolt prep.

Can I put a T-strike in a hollow metal frame?

Only if the frame was ordered with a T-strike prep. A standard hollow metal frame has the 4-7/8" ANSI pocket, and a 2-3/4" plate leaves the rest of it open with no reinforcement behind the screws.

What does "extended lip" mean on a strike plate?

A lip longer than the 1-1/8" standard, measured from the screw centerline to the end of the lip. Schlage codes the length into the part number (10-025 138 is 1-3/8", 10-025 112 is 1-1/2", 10-072 200 is 2"); Don-Jo lists the EST-115 at 1-1/2" and the EST-158 at 1-5/8".

Next step

Write four numbers on the order (pocket height, pocket width, corner, latch-center-to-frame-corner) and pick the plate: the Schlage 10-025 112 ANSI strike for a hollow metal 4-7/8" prep, the Schlage 10-072 100 box strike for L9000 mortise locks and wood frames, the Schlage 10-078 deadbolt box strike for an L400 in a 4-7/8" prep, the Don-Jo ST-261 for commodity 4-7/8" replacements, and the Schlage 10-027 full lip strike for the round-corner pocket; the deadbolt itself lives in the commercial deadbolts category. Orders placed before 3:00 p.m. EST ship the same day from Brooklyn, NY by UPS or FedEx, ground shipping is free at $450 and up, and stock items return within 30 days uninstalled with a 15% restocking charge. If the pocket matches none of the three preps or the frame is labeled, call the commercial desk at 718-814-6300 with the dimensions and the lock model.