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published: Saturday 5 March 2016
modified: Saturday 5 March 2016
author: Hales
markup: textile

Repair: busted laptop hinge mounting point

Even though this page will be short I'm putting up this repair because I think it's interesting reference material. I might start putting up all of the little repairs I do around the place, even if they just end up being picture.

Background

A friend came to me with their laptop for repair. A screen hinge had detached itself from the body of the laptop. Whenever you opened or closed the laptop the plastic body now flexed considerably in ways it should not.

For those not familiar with laptop hinges: they're friction hinges. In order to keep the lid of the laptop in one position they are designed to be very difficult to rotate.

Ordinary users use the whole laptop lid as a lever so the friction is not a problem, but when the hinge unscrews itself then the relatively small hinge acts as a small lever inside the laptop's case, causing all manner of fun and destruction when people open and close the lid.

Problem and repair

This is the mounting point on the laptop body for the perfectly fine left hinge:

Three screws are inserted from above, through the hinge and into the brass inserts. These inserts are (supposed to be) strongly held into the plastic body. The fourth hole is for a screw that gets installed from underneath the laptop.

This is the dodgy right hinge mounting point:

Nothing missing here! Move along!

When I recieved the laptop one insert was already gone and the screws kept popping out of the others. I tried pop-riveting the hinge back into place, but this cracked out the remaining inserts.

In the end I filled the area with epoxy and installed over-size screws:

I left the laptop lid chocked open with some clamps to set overnight. The screws do not bite into the plastic body themselves but instead interface with the epoxy.

Now the right hinge seems to be strong and solid, however the only way to tell its true strength is to break it again.

Thoughts

These hinges have a remarkably small mounting footprint into only the tiniest amounts of plastic case. I'd say that these hinge mounting points are designed to fail.


Filesponge - Sunday 9 December 2018

Hey, thanks for the page here. I'm having to fix more and more of these broken bits of plastic. I guess the plastic just gets weaker as time goes by, and as I only supply older laptops I'm going to have to just put up with it lol.

It's a good idea using a load of epoxy, my own problem is finding one that's strong enough. Most grip for several opening/closings, and then it cracks up or breaks away from the plastic itself.
I don't mind so much if it's on the base plastics as I've managed to fix most using screws and bolts that are hidden underneath the laptop. The problem for me is when it's a lid that can't be found anywhere :-(

Very frustrating, and does show how cheaply these things are thrown together. Metal inserts gripping thin cheap plastic ? Great idea HP, ACER, PACKARD BELL.....oh, well yes it's any and all of them ;-)

Hales - (site author) - Sunday 9 December 2018

Hey /dev/filesponge,

Metal inserts are actually a good idea -- they spread the load over a larger area of plastic. Without the metal inserts (or metal plates, or something similar) we would have screws going directly into plastic threads.

You are right about companies horribly executing the use of metal inserts, however. My current laptop (a refurb Dell 11.6") recently popped an insert on the lid side of a hinge. Magically this has _fixed_ another problem: a permanently noisy (think haunted house door) lid hinge.

I suspect the problem comes down to uneven loading on the inserts. The hinges are small parts. Even a small rotational misalignment (on the wrong axes) would lead to the lid open/close forces being concentrated on single inserts rather than shared equally (and make my haunted noises). A solution might be to use hinges with larger plates or better tolerances design.

> Very frustrating, and does show how cheaply these things are thrown together

Yep. I don't think there's much out there that looks like the manufacturers care about experience after sale. :(

> It's a good idea using a load of epoxy, my own problem is finding one that's strong enough. Most grip for several opening/closings, and then it cracks up or breaks away from the plastic itself.

In the laptop shown above I had a very large area to spread the epoxy over, with lots of internal plastic structure to grip onto. It might even be worth breaking some plastic if you don't have enough space, because the epoxy will replace it anyway.


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