Knob Lock Order Guide: Light or Heavy Duty, 6 Functions
Order a knob lock by duty, function and door prep: 587 for standard residential doors, 5870 or 5831 for offices and schools, ET for entrance, BK for privacy, PS for passage. Most of these cylindrical knob locks fit doors 35mm to 50mm thick at a 60mm or 70mm backset.
The set to order
| Part | What to check | Models |
|---|---|---|
| Light duty entrance knob lock | 1 per door. Key outside, turn button inside. Doors 35mm to 50mm. Backset 60mm standard. | 587 SSET, 587 PBET, 587 MBET |
| Light duty privacy knob lock | 1 per door. Turn button inside. BK means bathroom, not black. | 587 SSBK, 587 PBBK, 587 MBBK |
| Light duty passage knob lock | 1 per door. No key and no button. Polished brass. | 587 PBPS |
| Heavy duty entrance knob lock | 1 per door. Listed for commercial offices, schools and heavy-duty residential. Check the backset of each model. | 5870 SSET, 5870 ACET, 5871 SSET, 5831 SSET |
| Heavy duty privacy knob lock | 1 per door. Doors 35mm to 50mm. Turn button inside. | 9210 SSBK |
| Commercial function knob lock | 1 per door. Storeroom, classroom and exit latch. Doors 35mm to 45mm. | 5807 SSR, 5807 SSCR, 5807 SSEL |
| Lever alternative | 1 per door where a knob is not accepted. Doors 35mm to 45mm, 60mm backset. | LH853 SNET |
| Deadbolt | 1 per exterior door, above the knob lock. 25mm throw. Single cylinder, thumbturn inside. | D101 SS |
| Flush bolts | 2 per inactive leaf on a pair, top and bottom. Doors 30mm to 45mm. | FB001 |
Light duty or heavy duty
All of these are cylindrical locks: our photographs show a solid chassis filling the bore, with the latch hooked onto it. That chassis takes the turning load, which is the difference from a tubular lock.
Light duty and heavy duty are our product lines, not a BHMA grade. If your specification calls for a grade, send it with the order and have it confirmed.
Cylinders on 5870 SSET, 5871 SSET and 5831 SSET are 5-pin tumbler with a brass plug. 5870 SSET comes with three keys, 5871 SSET and 5831 SSET with two.
| Models | We list it for | Trim | Door | Backset |
|---|---|---|---|---|
| 587 (light duty) | Standard residential use | Wrought stainless steel or brass | 35mm to 50mm | 60mm standard, 70mm and 90mm optional |
| 5870 ACET, 5874 ACET | Commercial offices, schools, heavy-duty residential | Zinc die-cast, electroplated, or solid brass | 35mm to 50mm | 60mm or 70mm |
| 5871 SSET | Commercial offices, schools, heavy-duty residential | Zinc die-cast, electroplated, or solid brass | 35mm to 50mm | 70mm standard, 60mm and 90mm optional |
| 5831 SSET | Commercial offices, schools, heavy-duty residential | Zinc die-cast, electroplated, or solid brass | 35mm to 50mm, confirm over 45mm | 60mm, 70mm, 80mm or 90mm |
| S578 | Entrance doors, residential or light commercial | Stainless steel or brass | 35mm to 50mm | 60mm or 70mm |
| 9210 | Entrance and bathroom doors | Stainless steel | 35mm to 50mm | Confirmed against your drawing |
| 5870 SSET | Commercial offices, schools, heavy-duty residential | Zinc die-cast, electroplated, or solid brass | Confirmed against your drawing | Confirmed against your drawing |
Six functions, and which door gets each
- BK means bathroom, not black. 587 MBBK is a matt black privacy lock, and MB is the color.
- 5807 models suit doors 35mm to 45mm, narrower than the rest.
- 5807 models list stainless steel 304/201, so state the grade you need on the order. For a coastal or wet location, ask for 304.
- 5807 SSCR: state which side the key must be on, and have it confirmed against your drawing.
- Passage in a finish other than polished brass is not listed: send the finish and we confirm it.
| Function | How it works | Door | Models |
|---|---|---|---|
| Entrance (ET) | Key outside, turn button inside | Front door, office | 587 SSET, 587 PBET, 587 MBET, 5870 SSET, 5870 ACET, 5874 ACET, 5871 SSET, 5831 SSET, S578, 9210 SSET |
| Privacy (BK) | Turn button inside, no key | Bathroom, bedroom | 587 SSBK, 587 PBBK, 587 MBBK, 9210 SSBK |
| Passage (PS) | Both knobs turn, nothing locks | Corridor, closet | 587 PBPS |
| Storeroom | Outside knob fixed, opened by key only. Inside knob works the latch. Latch deadlocks when closed | Store, plant room | 5807 SSR |
| Classroom | Key locks or unlocks the outside knob. Inside knob always free. Latch deadlocks when closed | Classroom, meeting room | 5807 SSCR |
| Exit latch | Blank rose, worked from one side. Deadlocking latch | Door that opens from one side only | 5807 SSEL |
The door prep
Stop the cross bore as soon as the tip of the bit shows, then finish it from the opposite side, so the veneer stays intact. On steel doors, have the door maker prepare the bore to the same drawing. If the doors are already cut, measure the bore and backset on site and send them with the order: a knob lock cannot correct a wrong hole.
| Item | Size | Note |
|---|---|---|
| Cross bore | 54mm (2-1/8 in) | Common North American prep. Not stated per model, so confirm against your drawing |
| Edge bore | 25mm (1 in) | Drilled from the door edge into the cross bore |
| Backset | 60mm (2-3/8 in) or 70mm (2-3/4 in) on most models | Door edge to bore center. Must match the latch you order |
| Latch faceplate | Recess in the door edge | Two screws, as photographed |
| Strike | Recess in the frame | 587 SSET is photographed with a strike and a plastic strike box |
| Height | About 965mm (38 in) to bore center is common in North America | Follow the project drawing, and match the other doors in the building |
Knob or lever
A knob needs a tight grip and a twist of the wrist. On doors covered by the 2010 ADA Standards in the United States, section 404.2.7 rules that out, so public buildings there use levers. Order a lever set such as LH853 SNET on those doors, and confirm the requirement for your project with the local authority.
An exit door must open from inside without a key. The International Building Code and NFPA 101 also limit the number of actions needed to open it. Check the function before you put any knob lock on an escape route.
Quantities per door
D101 SS suits doors 35mm to 45mm at a 60mm or 70mm backset, so it stops short of the 50mm the knob lock reaches. Fit it above the knob lock on the same door edge, at the same backset. Heavy duty models can be keyed alike to deadbolts, and 587 can be keyed alike to the deadbolt series or master keyed, which saves carrying two keys. On a pair used as an exit, manual flush bolts are often not accepted: check with your local authority.
| Door | Knob lock | Other lines |
|---|---|---|
| Apartment or house entrance | 1 entrance (ET) | 1 deadbolt D101 SS above it |
| Bathroom or bedroom | 1 privacy (BK) | None |
| Store room | 1 storeroom 5807 SSR | None |
| Classroom | 1 classroom 5807 SSCR | None |
| Pair of doors | 1 on the active leaf only | 2 flush bolts on the inactive leaf, top and bottom |
What goes wrong on site
- BK read as black: a bathroom lock arrives on a door that needed a key.
- A 50mm door with 5807 or a tubular lock: those listings stop at 45mm.
- Backset assumed: 5871 SSET is 70mm as standard, not 60mm.
- Latch fitted backward: the slanted face must meet the strike as the door closes.
- Strike set too far off: on keyed functions the small deadlocking pin must rest on the strike plate. If it drops into the hole, the latch can be slipped.
- Strike screws too short on an entrance door: the frame is the part that gets kicked.
- Mixed finishes on one floor: 5870 ACET and 5874 ACET are antique copper, and 587 passage is polished brass.
What to send
- A door schedule by function, with counts.
- Door thickness and material.
- Backset, and cross bore if the doors are already cut.
- Duty: residential, or offices and schools.
- Model code and finish.
- Stainless grade on 5807 models.
- Keys per lock, and keyed to differ, keyed alike or master keyed, with the door list.
- Whether any door is on an escape route or an accessible route.
Questions buyers ask
What is a knob locking system?
It usually means a cylindrical knob lock: two knobs and roses on a chassis, a latch and a strike. You choose one function per door, and the keying joins the locks into a system. Send a door schedule and we match a model to each door.
How do I choose between light and heavy duty?
Use 587 for standard residential doors. Use the heavy duty models for offices, schools and busy homes. Compare the backset and trim in the table, because they differ by model more than the name suggests.
What is the difference between a cylindrical and a tubular knob lock?
A cylindrical lock has a chassis filling the bore, and our models reach 50mm doors. A tubular lock has a separate latch and nothing else in the bore, and our models stop at 45mm.
Can knob locks be keyed alike or master keyed?
587 lists keyed alike to the deadbolt series or master keyed. 5870, 5871 and 5831 list keyed alike to deadbolts, and 9210 lists group keying and master keying. State it on the order with the door list.
Can I use a knob lock on an exit door?
Only where the inside opens without a key, and where the code accepts a knob. Check the function, check the accessibility rule, and confirm with your local authority. On a panic door, order an exit device instead.
Sources
Codes change and vary by place. Confirm with the authority for your project.