Installing a Double Cylinder Deadbolt in Devore

What to know first in Devore

A standard single-cylinder deadbolt has a key cylinder outside and a thumbturn inside. A double cylinder replaces the thumbturn with a second key cylinder, keyed alike so one key works both faces. The bolt, housing and strike are the same; the difference is that nobody can open the door from inside without a key. That is the whole point, and also the whole risk. The attack it defends against is specific: a burglar breaks glass in the door, a sidelight or a nearby window, reaches in and turns the thumbturn. If no glass sits within arm's reach of the thumbturn, a double cylinder adds nothing against kicking, prying or drilling, and it adds a lock-in hazard. In Devore, we start every double cylinder deadbolt installation by measuring where the glass is, what the door is used for, and whether the bolt and strike behind it are strong enough to deserve the upgrade.

Work included on a typical visit

• Exit and code check before we drill. Our quote begins with a conversation: which door, how many exits, who sleeps where, what's on the other side of the glass. That tells us whether a double cylinder is a sound security measure or a hazard. We put the reasoning in plain language so you can decide with the facts.
• Workshops, detached garages and outbuildings. Detached garages, workshops, pool houses and barns often have glass-panel doors and nobody sleeping inside. A double cylinder deadbolt works well there. We install it on a reinforced strike, key it alike with your other outbuilding locks if you like, and suggest keeping a spare key inside the main house.
• Interior storage rooms and secured closets. Rooms holding records, equipment or wine often need a lock that can't be turned from inside by a child or guest. A keyed-both-sides deadbolt does that. We install one on rooms that aren't sleeping spaces and aren't on an escape route, and we keep the keying simple.
• Thick doors, French doors and narrow stiles. A French door's stile has to hold a hole roughly two inches across plus a latch pocket, with room to spare beside the glass stop. We measure stile width and thickness before quoting. If the stile is too narrow, we say so and suggest a surface-mounted or narrow-stile lock instead.
• Strike, jamb and frame reinforcement. A glass door is often weaker at the frame than at the lock. After installing the double cylinder, we fit a box strike with 3-inch screws into the framing, check the hinges and look for split wood at the strike. The deadbolt is only as strong as what it lands in.

What's different about Devore

On larger properties around Devore, outbuildings such as workshops, equipment sheds and guest cottages often have glass-panel doors far from the house. A double cylinder deadbolt suits those buildings when nobody sleeps inside. We install it on a reinforced frame, key several buildings alike and keep the ring manageable. Long driveways make break-ins easy to miss, so the lock and strike should be heavy.

Barns and tack rooms in horse country near Devore often have windowed doors, and tack is valuable. A double cylinder can protect a glass-panel tack room door, provided the barn's emergency exits stay free. In a barn fire, people and animals must move quickly, so we recommend keeping main barn doors operable from inside and using a keyed-both-sides lock only on a closet-style tack room.

Hillside and foothill homes near Devore face wildfire evacuation risk and sometimes steep exterior stairs, so a quick exit matters. Smoke and darkness make the seconds a key hunt takes dangerous. A double cylinder on the main exit is a poor trade. We recommend a standard deadbolt on main exits and keep any keyed-both-sides locks for outbuildings that aren't part of an evacuation route.

Example situations

• A landlord in Devore owns a duplex. After a break-in through a rear door's glass, he asks for double cylinder deadbolts on both back doors. We explain that tenants must be able to leave quickly without a key, and that heavier single-cylinder deadbolts with long-screw strikes address the break-in better. We install those, and he arranges laminated glass for the panes.
• A daughter in Devore asks about a double cylinder on her father's door because he has started wandering at night. We explain the fire risk: if he can't get out, neither can anyone helping him. We suggest door chimes, a different lock layout and a talk with his care team. We aren't care specialists, but we can help you find a lock that doesn't create a trap.
• The owner of a boutique has a glass-panel rear door with a thumbturn within reach of the pane. Employees use that door to leave, and it opens onto an alley. A double cylinder would slow an emergency exit. We install a Grade 1 single-cylinder deadbolt with a heavier strike, keep the thumbturn, and suggest security film on the glass so the front and alley doors keep their exit capacity.
• A small business near Kimbark Avenue keeps payroll records and electronics in a storage room with a glass transom. The owner wants a double cylinder so nobody can lock themselves in or turn the lock from inside. We confirm the room isn't an exit path, install a Grade 1 double cylinder deadbolt keyed to the owner's system, and point out that the lightly built door is now the weak spot.

Step by step with Julian's Locksmith

1. Talk through the door and the reason. Before we drive out, we ask three things: which door, how far the glass is from the thumbturn, and whether this is the way out in an emergency. Those answers tell us whether to bring a double cylinder, a single cylinder or both, so you can choose on site.
2. Check exits, glass and the people involved. This step separates a sound installation from a bad one. We confirm another exit exists, count the people who'd need to use it, and talk through the key plan. If we recommend against the lock, we say so before any drilling begins.
3. Measure, quote and choose the hardware. Hardware choices come next. Standard double cylinder deadbolts from Kwikset or Schlage suit most doors, while heavier Grade 1 or restricted-key models suit higher-risk entries. We show you what fits your door, what each option adds and what the total will be.
4. Prepare the door. We use a drill jig to cut the face and edge bores square, protecting the glass and finish with tape and padding. If the door is already bored, we clean and check the holes. A crooked bore makes the key bind, so we take care here.
5. Fit both cylinders, key them and set the strike. We mount the bolt, then fit the exterior and interior cylinders through the tailpiece, aligned so the keyway sits upright when unlocked. Both are keyed alike to your key. Then the strike goes in: a box strike with 3-inch screws into the framing.
6. Test the lock and plan the key. Before we leave, you operate the lock yourself, including in a dim room, to see what an emergency exit would feel like. We help choose a spot for the key, check that a guest could find it and confirm every key works.

What affects the cost

• Lock grade and brand. Fewer models are made in double cylinder form than single, so the selection is narrower. Kwikset, Schlage and heavier commercial lines all offer them. Grade and finish drive cost, and restricted-key models from Medeco or Mul-T-Lock rise further. We tell you what is in stock before we quote.
• Keys and keying. Decide how many keys the household needs and where each one lives. Since the key is the way out, an extra copy for the key hook and one for a spare spot are common. We include whatever count you choose in the quote.
• Glass protection you add separately. If you pair a single cylinder with protected glass, budget for both. We handle the lock and hardware, and a glazier handles the glass. Sometimes that combination costs more than a double cylinder, but it keeps a thumbturn on the inside.

Every job gets a clear quote before any work starts. Call (951) 903-3193 with the details and we'll tell you what to expect for your situation in Devore.

Advice before you book

• Hang the key where a person leaving can reach it in the dark but a person outside cannot. A hook beside the door, high enough that small children won't play with it, is common. Keep it in the same spot every day. A key tucked in a drawer across the room defeats the safety point.
• Check your insurance and local rules before installing. Policies, leases and HOA rules differ, and we can't speak for your carrier. A short call to your insurer and to the local building or fire department can prevent trouble at renewal, at inspection or when you sell the house.
• When children live in the home, think about the key's reach rather than its secrecy. A hook set too high can leave a nine-year-old unable to get out. Pick a spot older kids can reach, explain that it's for emergencies, and rehearse until they can do it without help.
• Never leave the key in the interior cylinder as a habit. A hand reaching through broken glass can turn it just like a thumbturn, and you've gained nothing over a single cylinder. If you can't keep the key somewhere else, a double cylinder isn't the right lock for that door.

Mistakes to avoid

• Putting a double cylinder on the main exit and hiding the key far away. In a fire, that costs seconds nobody has. Households do it because a pane of glass worries them. Protect the glass instead and keep a normal thumbturn on the door your family relies on to leave.
• Giving out one key and no plan. A single key hung on a nail that only one family member knows about leaves everyone else dependent on that person. Spread the knowledge: everyone who lives there needs to know where the key is and how to use it.
• Assuming a double cylinder stops all break-ins. It targets the reach-in method only. A kick, a pry or a drill doesn't care which kind of cylinder is on the inside. Reinforce the strike and frame too, or the lock protects against one attack and ignores the others.

Getting to Devore

Devore is about 8 miles from our San Bernardino base, roughly 14 minutes in light traffic via Kendall Drive or Palm Avenue to I-215 North, through the Devore junction onto I-15 North, exit Kenwood Avenue for Devore Heights. When you call, you get an arrival estimate based on where the technician is and the traffic at that moment.

Commercial jobs on busy stretches like Palm Avenue sometimes need a parking plan, especially for storefront doors or roll-up gates. Let us know about loading zones, red curbs or parking structures before we arrive.

About Devore: Cajon Boulevard through Devore is an original stretch of U.S. Route 66, which crossed the Cajon Pass from 1926 until 1979, when Interstate 15 replaced it.

New or replacement locks in Devore?

Call (951) 903-3193 and tell us which doors and what kind of hardware you have in mind. If you already bought the lock, keep the box handy so we can check it fits the door, and we'll quote the install before any work starts.