By Kent · Lock Depot Staff Writer

Two boxes, same footprint, different locks

You are putting a mortise lock on a steel gate or a pipe-frame door, and a mortise case will not bolt to a bare tube. It needs a box welded in to hold it. Keedex makes that box in two versions that look nearly identical on a spec sheet: the K-BXMOR1 and the K-BXMOR2. Pick the wrong one and you find out after the weld is cold. This is how to avoid that.

The only question: whose mortise lock?

Both boxes are made for mortise locks, not cylindrical ones. The listings name the locks each one is built around, and that list is the whole decision.

• K-BXMOR1 is listed for the Schlage L series, Sargent 7800 and 8200, and Yale 4600, 8600 and 8700.
• K-BXMOR2 is listed for Corbin Russwin 5000 and ML2000, Falcon M, and Best 34 through 37H. The listing title says "for Corbin and Stanley."

So the split is by lock family. Schlage, Sargent and Yale go in the MOR1. Corbin Russwin, Falcon and Best go in the MOR2. That is the reason Keedex sells two boxes instead of one.

The listings do not describe the internal cutouts, and I am not going to guess at them. What the listings give us is which locks each box is built for. Go by that list, not by how the box looks sitting on the bench.

What they share

From the listings, both boxes carry the same size and build:

• Size: 8-1/8 in. high by 4-5/8 in. wide by 1-3/4 in. deep.
• Material: 14 gauge steel.
• Backset: 2-3/4 in.
• Type: mortise lock.

Fourteen gauge is a heavy box, and it is the right call on a gate that gets kicked, slammed and left open in the wind. It also holds its shape when you weld next to it, which matters, as you will see below.

Check the backset against your lock

Both boxes are 2-3/4 in. backset. A mortise lock is a specific part, and not every one is cut for 2-3/4. Read the backset off the lock you are installing before you order. If it does not match, the box is not the problem. You need a different lock or a different box.

Our Keedex gate box guide covers the cylindrical side of this: choosing the box by the lock and not by the gate, guard rings, and the welding order. Read it if you are weighing a cylindrical lock against a mortise.

Welding order and heat

These are weldable boxes. A few rules from years of hanging locks on steel:

1. Dry fit first. Hold the box where it will live, set the lock case in it, and check that the spindle lines up with where your trim will sit.
2. Tack, do not run a bead. Four small tacks hold it. Check square. Then finish. A long continuous weld pulls the box out of shape as it cools, and a racked box binds the lock case.
3. Weld the box empty. Never weld with the lock case inside. Heat travels through the steel, and a case with springs and a latch in it will not survive it.
4. Grind smooth, then paint. Raw weld on an outdoor gate rusts first at the seam. Prime and paint the seam the same day.

On an outdoor gate, rust kills the installation, not the lock. A weathered box with a seized case is a service call you did not need.

Common mix-ups

"I have a Schlage L, so I need the Schlage box." Right idea. Keedex does not name its boxes by the lock. The MOR1 is the Schlage L box.

"It is a Best lock, I will use the MOR1." No. The Best 34 through 37H is on the MOR2 list. This is the one that catches people, because they think of Best as its own thing.

"A mortise box and a cylindrical box are close enough." They are not. A cylindrical box is a small bore. A mortise box is a deep pocket for the whole case. You cannot swap them.

"I will use the electric strike box." Different job. Keedex sells a separate weldable box for electric strikes. It does not take a mortise lock.

Which one to buy

Look at the lock you already have, or the one the customer specified. Find its family on the two lists above. Buy that box. If the lock is not on either list, stop and ask. Do not assume the nearest family is close enough.

Where these boxes earn their money

A mortise box makes sense where the gate or door gets real use: a back lot gate, a stairwell cage, a utility yard, a pipe-frame door on a loading dock. The mortise case is a commercial lock, built for a steady stream of traffic, and the box is what lets you hang it on steel instead of wood. A cylindrical lock on a gate box is the cheaper route and it has its place. When the building already runs Schlage L, Sargent, Corbin Russwin or Yale mortise hardware, a matching mortise lock on the gate lets the whole site run on one key system.

That last point is worth the extra money. A gate lock that takes the same cylinder as the building means one key ring, one rekey, one master key chart. Two key systems on one property means the maintenance man carries two rings and loses one.

Before you order, measure three things

1. The lock family and series, off the lock itself or its box. This picks the box.
2. The backset the lock is built for. Both boxes are 2-3/4 in.
3. The room on the gate. The box is 8-1/8 in. tall and 4-5/8 in. wide, so a narrow gate stile may not have the room to carry it. Hold a tape to the gate and check before you buy.

Common questions

Will the K-BXMOR1 take a Corbin Russwin lock?

The listing names Schlage L, Sargent 7800 and 8200, and Yale 4600, 8600 and 8700. Corbin Russwin is on the K-BXMOR2 listing, so use that one.

What is the gauge of the steel?

14 gauge, on both boxes.

What backset do they take?

2-3/4 in. on both.

Are they sized for cylindrical locks too?

No. Both are listed as mortise lock boxes.

Can I weld with the lock inside?

No. Weld the empty box, let it cool, then install the lock.

Browse the full line on our Keedex page. Send us the lock model and the gate type and we will confirm the box before you cut anything.