Bit Lock Upgrade

When locksmiths get together, we naturally talk about locks. We'll talk about all the different kinds of locks we sell and install. Somebody will mention knob locks and lever locks, and another technician details deadbolts. Then we get into a discussion about electronic locks, magnetic locks, bit locks, padlocks… wait a minute, and did somebody mention bit locks? You know, those locks that use "skeleton" keys.

Yes, there are still homes that use bit locks on a daily basis. Usually the exterior entry doors have been replaced or upgraded with the installation of cylindrical locks and deadbolts. Sometimes a rim lock or deadbolt is just installed above the old bit lock, turning the bit lock into a passage lock.

The front door on the example home utilizes an old Clinton mortise entry lock. In the 1970s, a Schlage B460 deadbolt was installed above it.

The rear door is still secured using a bit lock. Last year, a Weiser Powerbolt was installed above the bit lock. For convenience, a Schalge B160 outside cylinder and trim was used to match keying for the other doors. It fits into the Weiser keypad and inside control unit without any additional modification.

A side entry door into the house has a bit lock and Schlage B460 deadbolt installed above it. In a house like this, for every front door that needs nothing additional, there are 6 to 10 interior doors that still contain old and possibly broken bit locks. The three entry doors aside, this house has nine interior doors with unattractive, dull, semi-functioning bit locks.

When this homeowner decided to keep the old look (the doors, woodwork and banisters have never been painted over), it was a natural to try to refurbish or replace the bit locks.

Taking one lock out to use as a sample, he first went to local hardware store. The person in hardware told him those locks weren't made anymore, so he'd need to install modern knobs and wrap-around cover plates.

A local locksmith then suggested that he take the parts to a local metal plating company and polisher, but that still didn't solve the non-functioning lock problem. As an alternative, the locksmith said he would try to get information and would contact the homeowner. I received a telephone call from the locksmith, asking if I had any suggestions.

A quick trip to the distributor catalog revealed a couple of different options. If the lock case is repairable or in good working order, the homeowner may want to consider just upgrading the cosmetics on the door surface.

Here are some of the different choices available.

Kaba-Ilco offers:

Brass Knobs and Fixed Spindle - Part #197-03-51

Glass Knobs and Fixed Spindle - Part #199-03-51

Escutcheon Plate Set - Part #211-03-51
MAG Security offers:

Solid Brass Door Knob Set and Fixed Spindle - Part #8866-PB

Brass Plated Steel Door Knob Set and Fixed Spindle - Part #8869-B

Glass Door Knob Set and Fixed Spindle - Part #8866-G

Mortise Trim Plate - Part #8784
When servicing bit locks, remember that most interior bit locks use a fixed (one-piece) spindle, while exterior entry doors may use a split (two-piece) spindle. Both Kaba-Ilco and MAG Security offer round rosette trim plates if that is the style you are replacing. Also available are separate pieces such as the strike plate, mortise lock bodies and spindles.

Depending upon the condition of the lock and the trim, a better alternative might be replacing the whole lock assembly. By spending a little more than you would for the trim components, you can purchase a complete lock. Replacement locks are a functioning mortise lock with a deadbolt, two bit keys, a pair of full escutcheon plates, a strike plate and a pair of knobs with a fixed spindle. Depending on availability, it may be easier to buy a complete lockset with brass knobs and then upgrade by purchasing glass knobs separately.

Kaba-Ilco offers Bit Key Mortise Lock Set with Brass Plated Knobs - Part #215-04-51. MAG Security offers Bit Key Mortise Lock Set with Brass Plated Knobs - Part #8785 and Bit Key Mortise Lock Set with Glass Knobs - Part #8786.

For our upgrade, we're using the Kaba-Ilco 215-04-51 lockset. We'll also be using the MAG 8866-G glass knob and spindle set in place of the brass-plated knobs supplied with the lockset. The mortise case is a standard size (4" tall x 3" deep x 9/16" wide) and will replace most older interior door bit locks.

Before starting, test the door to see if everything works. This may come in handy later. Remove the old lock from the door. While you're at the door, check the hinges and frame alignment. Suggest any needed repairs to the homeowner and give him your estimated price to do the work.

The installation process for these locks is pretty basic. But there are some variables.

After checking the lock for fit, install the new case. In some older locks and doors, the mortise pocket may need to be enlarged.

The next step is to check for proper alignment of the key and spindle holes. The faceplate of the new lock may require some modification to the face of the door. The replacement lock has a slightly taller face. We used a sharp wood chisel to remove about 1/8" on the top edge of the face mortise.

The case mounting screw holes were also slightly offset from the old holes, a good thing in many doors where the old holes are stripped or worn out.

The escutcheon plates from both manufacturers are also a standard 2-1/4" x 7" size. They should cover all or most of the old plate area. In this case, the plates were about 1/8" narrower than the old ones. They also were slightly offset from the old trim. Once installed, they sat about 1/4" lower on the door.

Since these two-panel doors were still the original wood finish, the "finished" result is not a problem and the uncovered area is barely noticeable. If your customer's doors are painted, they may need some touch-up. If the old escutcheon plates were removed when the door was painted, it should be OK. If not, the visible area may be painted a different color, undetectable before but now visible.

Insert the spindle with one knob attached through one plate and insert it into the case. Slip the other plate over the spindle and screw the other knob on, and then tighten the setscrew lightly. At this point, line up one escutcheon and check for a level spindle alignment.

Tighten one of the escutcheon screws. Screw the second knob into position and tighten the setscrew. Again, the screw locations were slightly different from the old, allowing screws to bite into undamaged wood.

Align the second plate and install one the screws.

Check for smooth operation of the knobs. They should turn smoothly and the spring should return the latch bolt to its projected position without help. Since the spindles are square, each knob can be tightened in any one of four positions. If the latch stays fully or partially retracted, loosen the setscrew and loosen the knob one-quarter turn, then re-tighten the screw. Repeat this process on opposite sides of the door (keeping the spindle length centered) until it all works properly.

If the spindle is not level when you install the escutcheon plates, the lock may bind and you may need to slightly reposition one or both of the plates. After the case and trim is properly aligned, install the remaining trim screws.

Finally, prepare to install the replacement strike plate. Project the bolt, close the door softly against the frame and lightly mark the bolt and latch height with a pencil.

Remember checking the operation of the door before you started? The old strike may or may not have been aligned properly, so just putting the strike in the old position may not give you the best results.

Align and install the strike plate, mortising or shimming as necessary. Check the latching action and throw the deadbolt with the key from each side.

What else is there to do but write up the bill? As you can see, there isn't a lot of cost or labor involved in these upgrades.

However, you do have a couple of great opportunities. Use this visit to the home to offer a free home security check. Offer to examine the windows and sliding doors, and don't forget the garage doors. Did you notice that new car in the driveway? Let them know you can make duplicate transponder keys.

Talk to the homeowner about better entry door security if it is warranted. Offer to show the customer alternatives for entry and security. The Weiser Powerbolt is a good example of someone else up-selling. Suggest a video entry phone to replace the doorbell.

Be sure you hand them an informative flier about the other services your company offers. What better time is there to make an additional sale?

Our example home for this article is about 90 years old. There are hundreds more like it in this city and thousands more potential customers in this region. Just because a house is old it doesn't mean there is no opportunity to sell your products and services.

For more information on the bit key products, contact your favorite locksmith distributor. Or call Kaba-Ilco at (800) 849-8324, MAG Security at (800) 624-9942 or Nostalgic Hardware at (800) 321-1115. Websites are and