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Mortise Deadbolt
National Lock Supply offers a full line of Mortise Deadbolts from a variety of manufacturers. We have a selection of functions and finishes to match your architectural requirements.
Frequently Asked Questions
What is a Mortise Deadbolt?
A Mortise Deadbolt is a deadbolt-only lock body that installs into a mortised pocket in the door edge, with the bolt projected/retracted by a key cylinder and/or inside trim (like a thumbturn), depending on function.
How is a Mortise Deadbolt different from a bored (cylindrical) deadbolt?
Mortise deadbolts mount in a rectangular door pocket (mortise prep), while bored deadbolts mount through standard round cross-bore/edge-bore holes—mortise styles are commonly chosen for more robust commercial assemblies and trim options.
What functions are common for Mortise Deadbolt locks?
Typical functions include cylinder x thumbturn (F17), double cylinder (F16), cylinder only / blank inside (F18), and classroom deadlock functions (often F29 variants depending on series).
What do ANSI function numbers like F16, F17, F18, and F29 mean?
They’re standardized function identifiers used across many mortise lock families to describe how the deadbolt operates (key/key, key/thumbturn, key-only, classroom-style variations).
Are Mortise Deadbolts available in commercial “Grade 1” options?
Yes, this category includes multiple Grade 1 mortise deadbolt/deadlock models intended for demanding commercial use.
What cylinder/core options are available (conventional, SFIC, LFIC)?
Many mortise deadbolt bodies are offered less cylinder (so you can match your existing key system) and/or prepped to accept SFIC or LFIC interchangeable cores on certain series.
What door prep and backset should I look for?
Mortise deadbolts require a mortised pocket and faceplate prep; 2-3/4" backset is common on many commercial mortise bodies—always match the lock case/backset to the door’s existing prep.
Are Mortise Deadbolts fire-door compatible?
Some mortise lock products are UL-listed for fire door use (often referencing tests like UL 10C), but you must verify the specific lock’s listing and match it to the door’s fire label requirements.
What standards apply to mortise lock hardware?
BHMA publishes ANSI/BHMA mortise lock performance standards (such as ANSI/BHMA A156.13) covering operational, strength, security, cycle, finish, and dimensional criteria.
Which brands will I find in this Mortise Deadbolt category?
You’ll see mortise deadbolt/deadlock options from manufacturers such as BEST and Sargent, with additional commercial-series listings depending on function and trim.