GMS Interchangeable Cores and Knob or Lever Cylinders: IC6, IC7, LFIC, Construction Cores and K001

You have the old core in your hand, or a knob or lever lock whose cylinder needs replacing, and you need the GMS number that matches it. GMS builds the product type, keyway, finish and keying into that number, so a code such as IC7A26D or K001SC26DA2 can be read one field at a time.

GMS IC cores: IC6, IC7, LFIC, SIC (Sargent LFIC), CIC and MIC

The IC cores table in the GMS catalog, repeated on GMS's IC cores sell sheet, names six models and the keying each one comes with:

The SIC is the core GMS's website calls its Sargent LFIC. The catalog marks the MIC for use with the KIT-PIN03 pinning kit.

Start from the housing. Our SFIC vs LFIC guide explains why the core format has to match it. GMS housing numbers, and the IC-SP1-10 spacer GMS lists for a 6 pin core in a 7 pin ICM7 or ICT7 housing, are covered in our GMS mortise and rim cylinder guide.

How to read a GMS IC core number

The how to order table reads model, keyway, finish and keying, run together as in the catalog's examples:

• IC7A26D: IC7 core, Best A keyway, 26D satin chrome. In the catalog, only the LFIC number adds a keying code.
• LFICSCF4B1: LFIC core, SCF (Schlage F) keyway, 4 satin brass, B1 for 1-bitted.
• SICSA26D: SIC core, SA (Sargent LA) keyway, 26D satin chrome.
• MICSC26D: MIC core, SC (Schlage C) keyway, 26D satin chrome.

The IC6 and IC7 take the Best A to H, J, K, L, M, Q, R and DD keyways and the Arrow 1C and 1D. The T and W keyways (TA to TE, WA to WD, WG and WH) are listed for the IC7 only. That makes 28 small format keyways, as the sell sheet says.

The LFIC comes in SC, SCE, SCF and SX (Schlage C, E, F and C~K) and in G23 and G45 (Schlage C123 and C145). In G23 and G45 it is 1-bitted with no keys; the catalog prints that keying code as NB, the GMS website as BN. The SIC comes in SA, SAX, SLB and RA (Sargent LA, LA~LC, LB and RA), the CIC in CL4 (Corbin L4) and the MIC in SC. Our key blank guide explains keyways and key sections.

The finish column offers 4 satin brass, 19 black and 26D satin chrome for the IC6, IC7 and LFIC, 4 or 26D for the SIC and CIC, and 26D for the MIC.

GMS construction cores

GMS's construction cores sell sheet describes them as temporary cores that let contractors and facility teams control access during construction and renovation without exposing the final key system. The catalog calls them color coded and says they match the original manufacturers' codes; keys are sold separately. It lists ten:

The construction cores page of the GMS website shows the Schlage versions as LFICSC-ORG-A, -B and -C in orange.

K001, K002 and K003 knob and lever cylinders

For a key-in-knob or key-in-lever lock, the GMS catalog lists three models, one for each lock brand. The catalog and the knob and lever sell sheet say the K001 fits Schlage knobs, levers and deadbolts and comes with 5 tailpieces. The K002 fits Arrow knobs and levers, the K003 fits Sargent levers, and each includes 3 tailpieces. For Yale levers GMS lists the KIT-K001YA, which converts a K001; the cylinder itself is not included.

A K001 number reads model, keyway, finish and keying. Here is K001SC26DA2, the catalog's first K001 example:

K001 keying codes depend on the keyway group:

• AW, CB, KW, SC, SE, SX, WR and YA (Arrow 1179, Corbin 60, Kwikset 1176, Schlage C, Segal 9, Schlage C~K, Weiser E, Yale 8): drilled 6, pinned 5. A2 keyed alike in pairs, KD keyed different, OB zero bitted.
• CL4, RD1, SA, SAX, SLB, RA, SCE, SCF and YGA (Corbin L4, Russwin D1, Sargent LA, LA~LC, LB and RA, Schlage E and F, Yale GA): drilled 6, pinned 6. A2-6, KD-6 and OB-6.
• A62, AST, ASV, G23 and G45 (Assa A62, Twin 6000 and V10, Schlage C123 and C145): NK-6, sub-assembled with follower, no keys.

So K001G2326DNK-6, another catalog example, is a K001 in the Schlage C123 keyway, satin chrome, without keys. The K002 comes in AW and SC, the K003 in SA and SC, both keyed A2, KD or OB. K002AW4A2, for example, is a K002 in the Arrow 1179 keyway, satin brass, keyed alike in pairs. The finish column gives 4 satin brass, 26D satin chrome and 19 black. The catalog marks black as available in Schlage keyways; the GMS website lists it for the K001 only, in the SC, SCE, SCF, SX, G23 and G45 keyways.

For OB, GMS's general information page explains that its zero bitted cylinders are actually cut to a 1 bit or 2 bit, depending on keyway, and are packed with uncut keys for pinning. The website also lists UK-CON, a construction drilled plug offered in the K001SC26D only. Spare knob and lever tailpieces, retaining caps and retaining cap pins for the K001 and K003 are on page 34 of the catalog.

What to note before you order

• Type: IC core, construction core, or knob and lever cylinder
• Format and pin count of the housing or the old core
• Keyway of your key system
• Finish
• Keying: uncombinated, 1-bitted, keyed alike, keyed different or zero bitted
• For a knob or lever cylinder, the lock brand: K001 Schlage, K002 Arrow, K003 Sargent

Browse all GMS products, interchangeable cores and housings and knob, lever and deadbolt cylinders on our store.

Not sure which GMS core or cylinder replaces yours? Our customer support team is available Monday - Friday, 8 AM - 4 PM Central Time, at 1-888-800-7789 or [email protected].