Spring hinges are a great addition to any pair of eyeglasses. They let the temples (the long arms that rest on your ears) flex outwards, so that the glasses adjust to the shape of the head. This helps the glasses stay in place and makes them easier to wear for many people.
It isn’t all positive, however. Eyeglasses with spring hinges are more difficult to repair, and unless the spring hinges are of good quality, they are often the first thing to break in the glasses. Because of the way the hinges work, tightening or replacing a missing temple screw can be a tricky affair.
In this article I will explain how eyeglasses spring hinges work, why it is difficult to replace the small temple screws, and show you how to fix loose or missing screws yourself at home.
What is a spring hinge on glasses?
Spring hinges, also known as flex hinges, contain a small spring that lets the arms of glasses extend further than other types of hinges do. With traditional barrel hinges, the movement is usually limited to 90°. With spring hinges, however, you can move the arms out a lot further.
The benefits of spring hinges is that they provide more comfort, help the glasses stay on during physical activity, and require less adjustments than traditional hinges.
How does a spring hinge work?
Spring hinges use a spring-loaded plunger mechanism that is placed on or even inside of the temple (arm) of the glasses. When the temple is extended further outwards than its resting position, the tension on this mechanism pulls the arm back inwards.
In practice, this creates a snug fit that lets you know your glasses are always there.
What makes it difficult to fix a loose or missing screw on a spring hinge?
Because of the mechanism described above, when the small temple screw is not or only partially inserted, the plunger retracts into the mechanism because of the spring. The barrel hole on the temple is attached to the plunger, so this causes the hole to misalign with the other hole on the glasses frame.
When you try to drive the temple screw in when the hole is not lined up, you just end with a misaligned screw that can not be screwed in all the way, like so:
In order to properly drive the screw in and fix the temple to the frame, we must first align the holes. This can be done by extending the spring hinge by hand and then temporarily fixing it in place. I have described this process further down the page.
What do you need to fix the screw?
Not much, the most important things are a precision screwdriver and if necessary, a replacement screw.
The size of the screwdriver and screw depend on the exact glasses you have, but in most cases, a typical eyeglasses repair kit will have everything you need.
Can you fix the actual spring hinge if it is broken?
Unfortunately, no. The mechanism is quite small and intricate, and repairing it yourself when it is damaged is near impossible. You’ll need to go to an optician or eyeglasses repair company for this.
An external spring hinge can be replaced without having to replace the temple, but to do that, a professional will need to detach the original and solder a new one in place.
You can recognize an external spring hinge by the fact that there is a visible bulge on the side of the temple that faces your head.
An internal spring hinge, on the other hand, can’t be repaired or replaced. Typically the entire temple needs to be replaced, because the replacement comes with a fully working spring hinge.
Internal spring hinges are integrated in the temple itself and are practically invisible. This looks a bit nicer, but is regrettably also harder to deal with when it is broken.
Does this repair guide also work for sunglasses?
Yes, you can use this guide for both regular eyeglasses and sunglasses, as long as they have a spring hinge. You’ll typically find these on Ray-Ban glasses, but as far as I can tell, it should work on any pair of glasses with this type of hinge.
What about glasses with standard barrel hinges?
On glasses with standard barrel hinges, you won’t need to extend the hinge first. You can just screw a replacement temple screw in, or tighten it, if it is loose. Provided that the hinge is fully functional and not damaged, of course.
How to reattach a loose or missing screw on a spring hinge
What you’ll need
Needs to match the hinge/temple screw. Usually a small flathead.
Paper clips or push pins
Step by step
Make sure that you don’t use something fragile like a toothpick, because you don’t want it to break off and get stuck in the hinge mechanism.
A summary of the repair process
- Fully separate the temple (arm) from the frame of your eyeglasses.
- Hook the hole of the spring hinge onto something that will give you extra grip.
- Pull on the temple to fully extend the spring hinge.
- Insert a paper clip or push pin into the gap that opened to keep the hinge in its extended position.
- Take the temple and align it with the glasses frame.
- Carefully drop the small temple screw into the hinge.
- Use a precision screwdriver to drive the screw and secure the temple to the frame.
- Remove the paper clip or push pin that you used to keep the hinge open.
Once you know how the spring hinges on your eyeglasses or sunglasses work, it isn’t too hard to tighten a loose screw or even to replace a missing one. The trick is to extend the plunger of the hinge, and fix it in place before attempting to drive in the screw. If you don’t do this, the screw ends up misaligned and can not be driven all the way in.
Unfortunately, it isn’t possible to repair a broken spring hinge. Only a professional can do that for you. At best, you can replace the entire temple by yourself. If you manage to find a matching replacement temple and follow this guide to reattach it to the frame of the glasses, they should be as good as new.
- What a spring hinge is.
- How a spring hinge works.
- How to replace or tighten a screw on the screw hinges of your glasses.