Home Improvement

How to Fit a Bathroom Thumb Turn Lock

Bathroom thumb-turn locks are budget-friendly and a simple way to achieve a relaxing experience in your bathroom without worrying that someone will interrupt you. Your bathroom door lock not only gives you privacy but can also be opened from the outside in case of an emergency. It’s no wonder why so many people have these convenient and affordable.

Now, you are probably eager to know:

  • “What is a thumb turn lock and how does it work?”
  • “How to fit a thumb turn lock?”
  • “What tools and supplies do I need to fit it properly?”

Then, read along and learn how to fit a bathroom door lock.

What is a thumb turn lock?

Like any standard lock, the bathroom thumb turn lock (also known as a turnkey, thumb turn latch) allows you to prevent unwanted entry and embarrassing mishaps. So, you never have to worry about your privacy with a turn of a little knob. The difference comes from:

  • the highly specific thumb turn shape – knob with an oval/crescent form;
  • the way bathroom privacy lock works – unlike the other locks, these can quickly open a door from the outside.
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How does a thumb turn lock work?

In the simplest terms, you set the thumb turn clockwise to lock, and anti-clockwise to unlock. The mechanical explanation behind this is: when twisted, the thumb turn operates a deadbolt to lock/unlock the door from the inside of the bathroom. It’s simple as that.

Beyond this…

  • With a thumb turn lock, you turn your bath into a place for relaxation. You can enjoy a relaxing shower, bath, or meet your intimacy needs while preventing moments of awkwardness. 
  • This bathroom lock is easy to operate and safe. You can always get in if an accident happens with your children or vulnerable adults;
  • You can enjoy the comfort and durability you deserve. Some models have an “occupied/not occupied” indicator to show the locked/unlocked status of the door. So you no longer pull the handle and make unnecessary vigorous tests to enter.

Once you’ve chosen the bathroom thumb turn lock and are prepared for the work, it’s time to fit it. We warn you that the task may be tricky, tedious, and may cause hammering mishaps. So, better follow the professional’s thumb turn lock fitting instructions. Or, leave it to the lock fitters if you don’t feel confident enough.

Check the Fantastic Services website for price rates on door lock fitting and more!

How do you fit a thumb lock in a bathroom

Installing a thumb turn lock on a new bathroom door is straightforward. But if you wish to replace your tarnished, old-fashioned or faulty lock with a thumb turn, you have to pass one more step: the removal of the existing door hardware. To change the lock you you have to unscrew the current lock mechanism and alter the hole(s) to fit the new turn & release set.

This task could be challenging, but you never know until you try. So, let’s start by covering a few tips on how to fit a bathroom lock on a new door:

Tools and supplies you will need

  • Bathroom thumb turn handle
  • Bathroom door lock/bolt
  • Chisel
  • Hammer
  • Drill with drill bits
  • Tape measure
  • Tape
  • Pencil
  • Screwdriver
  • Screws
  • Safety glasses

Step #1. Measure where your new lock will sit on the door

When open, the door may move back and forth. So, use an extra hand to help out, a scrap piece of wood, a book, or a door wedge to support it before drilling. Then, step number one is to use the body of the lock as a template and mark the desired lock position.

No rules here. All you need is a place that is accessible, functional, and brings you ultimate comfort. As a guide, the height of your lock should be around 1m above the floor.

Use a standard pencil to mark the top and the bottom of the door lock mechanism on the door. Then, find the door edge centre-point and pencil in a straight, vertical line through the marked points to aid the drilling process.

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Step #2. Drill a hole for the door lock

Now, you have to drill with a suitable boring bit to make a hole for the lock. If you want to admire your work, the preparation tips below may be helpful:

  • Because you insert the lock mechanism into the door stile, double-check if the door lock mechanism width is less than the lock stile (this is the vertical area in the door frame);
  • Wrap a tape around the drill bit to control the depth of the holes. The latter should be as deep as the lock mechanism is wide. Turn to the lock manufacturer’s instructions for further details about the diameter of the holes. 
  • Keep the drill as straight and levelled as you can – you want to prevent it from going towards the edge of the door.

Once you have prepared, start upside down by making a series of drills down the vertical line you’ve already drawn. Allow the holes to overlap, so you can finally form a tunnel where the lock mechanism will be accommodated.

You see, the lock mechanism slot is bumpy. So, carve the holes with a sharp chisel to smooth the hole sides. Also, dust and wood chips will build up. Then, the vacuum cleaner will come in as a handy tool to suck them up. Finally, you only have to set the lockset into the hole and test if the diameter/depth of the tunnel is enough. If not, you can always adjust it.

Safety tips when drilling a hole for a thumb turn lock mechanism:
  • Before using a chisel or drill, put on your safety glasses to protect your eyes; 
  • Handle drills with care to avoid injuries; 
  • Chisel away from the body; 
  • Doors are usually heavy, so if you don’t have muscles, call a friend to help you out.
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Step #3. Create extra space for the latch plate

Once the “bed” for the lock mechanism is ready, your next step is to craft the recess for the lock to sit flush with the door. Here’s what to do step-by-step:

  • Start by pushing the lock mechanism through the hole and cover it with the faceplate. The key to precise work is to keep it levelled and mark around the edge of the faceplate with a pencil. 
  • After you take the lock mechanism off, proceed with a hammer and around 19 mm chisel to tap along the four edges you just made on the door edge. 
  • From the top horizontal line down the centre, make a series of 1-2 mm parallel cuts in small sections – the flat edge of the chisel should face up. The advantage of this method is that you can quickly remove the thin wood layer. 
  • Then, chisel out the notched layer of the timber underneath and inside the pencil outline until you are left with a flat and level base. The newly-formed recess should be as deep as the thickness of the faceplate.
Be careful here – this is precise work, so do it at a slow pace. A smart step is to push the lock plate every now and then to make sure you are not chopping too deeply.

Step #4. Drill holes for the handle and the thumb turn

Do you see the small holes inside the locking mechanism? This is where the screws for the handle and thumb turn spindle should fit into.

Just hold the door lock as straight as possible in position against the face of the door (next to the area where you will insert it into the door). Once you find the correct place, pencil in the handle spindle and thumb turn spindle to aid the drilling. Each mark corresponds to a screw hole, so remember to mark both sides of the door. Then, use the same wood drill bit and drill over the marks.

We warn you — don’t drill all the way through the door. Complete the drilling through the other side to prevent the risk of wood split and paint chips. You can also start with a 2mm drill bit to reduce the risk of splitting. Then, proceed with the correct size bit for the screw.

Things can get messy, so prepare a brush or a vacuum cleaner to remove wood shavings and debris.

Step #5. Fit the thumb turn lock mechanism in place

Once the thumb turn and handle holes are made, you need to secure the lock mechanism in place. Double-check if the spindle holes align. If everything is alright, push the lock mechanism through the opening, cover it with the latch plate and screw them in.

To finish the task, place the handle spindle through the hole and slide the handle on the spindle on the other side. Tighten them with screws.

Follow the same logic to fit the bathroom thumb turn spindle. Here, you have two options to consider:

  • The first: you cut the thumb turn spindle to a length that doesn’t allow it to appear on the opposite door side. 
  • The second: you leave its length as it is and install a screw device on the opposite door side. This idea is excellent if you are raising children because you will be able to open the door from the outside if they are locked out accidentally in the bathroom.

When you decide, pre-drill pilot holes and secure the thumb turn with screws. Finally, check if the handle operates the latch correctly and if the thumb turn is rotating smoothly. If not, the culprit should be the alignment of all components.

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Step #6. Recess a door strike plate into the door jamb

You can’t say the fitting of our bathroom thumb turn lock is done until you fit the strike plate. So, your next step is to locate it following the instructions by the lock manufacturer. If a template is not available, align the faceplate and the latch with the strike plate on the door jamb to create a preliminary outline of the last one. Use the markings as a reference to position onto the metal part on the door jamb.

With everything marked out, it’s now time to put the drill and chisel in action. Hollow out the hole for the bolt to form a 1-2mm recess — as deep as the strike plate. Do a light sanding if unwanted protrusions are in the way. This will help you remove the excessive wood until you reach the needed depth and the surface is flat.

The process produces a lot of dust and wood chips. For the finishing touches, clean them out with a vacuum cleaner and a soft lint-free cloth. Or, let the experts make your home sparkling clean. At the final line, remember to test-fit and secure the plate with screws. Ensure the lock works flawlessly. And don’t bother with any marks left from the pencil – you can rub them off with an eraser.

That’s it — you are all done.

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How to choose a bathroom turn and release lock?

You want a sturdy bathroom thumb turn lock that runs smoothly, resists corrosion, and withstands the test of time, don’t you? Here’s what you need to know about these quality bathroom locks:

  • The most reliable bathroom locks are ISO 9001 and BS EN 12209 compliant;
  • Because you rely on your bathroom door at least 5 -10 times per day, you need a lock designed for intensive use. Best-of-breed bathroom locks fall into the Grade 1 (>10,000 rotations) and Grade 2 (>25,000 rotations) categories, so make sure you pick one of these;
  • Complement your bathroom lock with your current plumbing fixtures. For example, if your faucet and shower are Polished Nickel, you might not want to choose a Medium Bronze bathroom thumb turn. Whatever model you choose, it’s worth investing in a high-quality product, so your new door hardware lasts a lifetime;
  • The turnkey itself and bathroom thumb turn lockset can be found in many variations and as stand-alone products to satisfy anyone’s needs. If there’s no reference that a door handle comes with a turn and release lock, get the lock mechanism and the other parts to ensure they all work together and keep the door secure.

Still confused? If you are not familiar with the technical jargon and the bathroom thumb turn lockset, check out the major parts:

  1. Lock mechanism (pretty self-explanatory)
  2. Door handle – mind both types: lever on “rose” door handles and lever handles on backplates – that’s a self-evident choice;
  3. Cover plate – the metal, decorative plate on the edge of the door that protects the door hardware;
  4. Thumb-turn – the rotating part that locks/unlocks the door.
  5. Strike plate (door strike) – the rectangular-shaped piece of metal that fits on the door jamb. It includes a hole where the bolt/latch extends to close the door.
Before you buy a thumb turn lock mechanism, remember to measure the door side rails to ensure it will fit.

What is the difference between a bathroom lock and a privacy lock?

A thumb turn lock might sound very much like a privacy lock, but there is a difference. Bathroom thumbturn locks have an emergency coin release on the exterior side of the door while the actual thumb turn mechanism is on the inside. The point is for you to be able to lock it when you’re inside the bathroom without anyone disturbing you. Still, in case of emergency, the door can be unlocked from the outside with a coin.

Privacy locks are quite similar. They also have a button or a tab that people turn when inside the room. The difference is that these locks unlock when you turn the handle from the inside. A small convenience, actually.

Not sure you can fit the thumb turn lock yourself?

While you might be enthusiastic and endlessly fascinated that you can fit a privacy lock, don’t try to do everything on your own. Lots of things can go wrong. For example, your hand may shake for a moment and you can damage the door. Even shaping a straight, square recess is a problem until you have mastered it.

In case fitting/replacing a thumb turn lock seems like a lot of effort, your best bet is to entrust the task to the professionals. From fitting a thumb turn lock on a new toilet/bathroom/changing room door to replacing the current lock mechanism, they can tackle them all! So, save yourself the hassle and let the Fantastic Services lock installers do the precise work instead of you. And if you want to know how much fitting a lock can cost you, our helpful post has the answers!

Need a local lock specialist to fit your bathroom privacy lock?

A Fantastic locksmith is up for the task!

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  • Whether you need to amp up your bathroom’s door aesthetics, enjoy improved privacy or protect your children, there is a thumb turn lock out there for you!
  • Fitting a bathroom thumb turn lock can be done in a breeze, but let’s face it — it’s a “bitter-sweet” project. You’ve got the opportunity of improved privacy, but also one wrong move, and you can end up on the expensive side.
  • Even if the turnkey fitting is not the hardest amongst the plethora of home improvement tasks, you may find yourself struggling with one or more of the steps. So, save time and extra energy by calling a local locksmith who has the know-how to do the job right the first time.

Now, it’s your turn. Please, share questions or further tips in the comment section below!

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