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I’d like to install a window lock to open/secure my double-hung aluminium windows by a few cms if I'm out or asleep.
Hello @Else
Would it be possible for you to post a few photos of your window? It will give our members a better idea of its construction, we'll then be able to offer recommendations on how to mount the locks to your window frame.
If you need further assistance, please let us know.
Eric
Hi @Else,
Unfortunately, because window locks are designed to lock the window in a fully closed position, they all seem to rely on the aluminium frames of the two windows lining up, which wouldn't be the case with the window being slightly open. I've had a good look and I can't find a lock that would be able to do this.
Maybe @Noyade, @Nailbag or @AlanM52 might know of something I have missed.
I've had a look online and seen a fairly simple solution that could work for you. Grab some timber that will fit in the channels on the side of the frame. This Porta 12x12mm 1.2m DAR Square Clear Pine might be a good option.

Work out how high you want the window to lift and then measure the space between the top of the window and the top of the frame when it is open. You can then cut a piece of your timber to length to fit in this gap. You could then use a piece of velcro on the top of the timber and the top frame to hold the timber in place.
You can then cut another piece of timber to sit underneath the window to hold it up.

The timber above won't allow the window to lift, while the timber below will hold it open.
It's not a perfect solution, but it will work.
Let me know what you think.
Jacob
Hi @Else,
With aging memory took a while to recall I have done this before with Stegbar aluminum sliding windows using the standard Whitco bolts.
As mentioned by @JacobZ that window (one of many in that double story house) used wood dowel for the ground floor windows.
Note the drilled hole in the frame that allows the window to be locked in the open position.
Wondering how we can turn that horizontal solution into a vertical one to suit your window(s).
Maybe this?
Raise the window to the desired open position and drill a hole to accept some sort of lock pin like a machine bolt.
Cheers
Hi @Else
From having to do this job myself a few times though only option is to mount a small window bolt lock sideways on the top of the bottom window. You will need to use separately purchased metal screws at a suitable gauge and depth. This is providing you are able to drill a hole in the side of the window frame to accomodate the bolt.
The other is to use a long throw sliding barrel bolt lock with a smaller diameter bolt and able to be mounted with finer screws, but won't be lockable, which should be an issue due to positioning. Its the far easiest solution if you want a lock type.
Nailbag
Thanks Jacob & Alan
Alan's suggestion is ideal as it allows me to lock the windows in the open position...
This second lock is really only so I can open the window by a few cms (e.g. at night or if I'm out) without worrying about security...
Any thoughts re. which particular window lock would be best/most discreet? Whitco & Remsafe sell a few versions....
Thanks Nailbag
Sorry I missed your response earlier... I'll investigate those options
Hello @Else
I suggest looking at the Remsafe White Lylock Push Lock, it is very similar to the lock that AlanM52 suggested in their post. It uses a low-profile pin to lock the window in place and will therefore not require as much space as a standard bolt lock.
If you need further assistance, please let us know.
Eric
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