By Kent · Lock Depot Staff Writer

Two housings that look alike and are not

A housing is the shell that holds an interchangeable core in a door. It is not the lock and it is not the core. You choose the housing for the opening, then drop your system core in. KSP makes two families that confuse people at the counter: the 407 and the 408. Both take a core. Both come less core. The difference is what is in the box and what the housing can be made to do afterward.

The 407: a mortise housing, one job

The 407 is a mortise housing. It goes into a mortise cylinder hole in the door, the same way a mortise cylinder would. The listing for the 407 SFIC housing says it is supplied less the screw-on cam and comes with a cam retainer and two screws. So you add the cam that fits your lock. That is the part buyers forget, and we cover it in our KSP 307 cam guide.

• KSP 407-26D: 6 and 7 pin mortise housing, less core, 1-3/8 inch cylinder length, satin chrome.
• KSP 407L 26D: the same idea at 1-3/4 inch, for the thicker door.
• KSP 407LFIC-26D: made for the Schlage large format core, less core, satin chrome.

One listing note. The 407LFIC page title and web address say 1-3/4 inch, and the description says 1-1/8 inch. We do not guess between them. Measure your door and confirm the length with us before you order that one.

The 408: a convertible housing with a cam pack

The 408 is built so one housing covers more jobs. The listing for the KSP 408-SFIC-US26D-CP6 says small format housing, less core, complete cam set. The large format version, the 408L-YALE-US26D-CP6, is listed as a mortise or rim housing in a pack with cams K700, K701, K702, K702-L and K702-S. The cams come with it, so you are not hunting for one on install day.

The 408 also takes an extension. The 408EXT housings add one inch to a 408, and the kit includes a stackable extension, a drive extension and screws. There is a small format extension and a large format extension. That matters on a thick door where the standard length leaves the core short of the face.

Which one to buy

Situation	Start with
Known mortise hole, you already own the right cam	407 in the length that matches the door
Mixed doors, different locks, one part on the shelf	408-SFIC with its cam set
Schlage large format core in the building	407LFIC or 408L, depending on the cam need
Door thicker than the housing reaches	408 plus a 408EXT

The honest rule from the shop: if you do one door, buy the 407 and the cam. If you service many doors with different locks, the 408 saves return trips, because the cams are already in the pack.

Match the core size before the finish

Check the core first. A small format housing will not take a large format core. If your building runs small format cores, you want the SFIC housings. If it runs Schlage large format, you want the LFIC versions. Our KSP SFIC core guide covers the core side, and our 307, 308 and 317 housing guide covers the neighbor family. The whole line is on the KSP page.

Finish comes last. The 408-SFIC is listed in satin chrome, bright chrome, bright brass, satin brass, satin bronze, oil rubbed bronze and flat black. Match the finish to the hardware the housing sits beside, and check stock on the finish you want before you promise a date.

Common questions

Do the KSP 407 and 408 come with a core?

No. Both are sold less core. You install a core from your own system.

Does the 407 include a cam?

The 407 SFIC listing says it is supplied less the screw-on cam, with a cam retainer and two screws. Order the cam separately.

What is in the 408 cam pack?

The large format 408L listing names cams K700, K701, K702, K702-L and K702-S. The small format listing says complete cam set.

Can I lengthen a 408?

Yes. The 408EXT extension adds one inch and comes with a stackable extension, a drive extension and screws.