Best metal for a rivnut in an aluminium door?

[Dave Rove]

I want to fit Yale door bolts to an aluminium patio door. ( This bolt:

)

The aluminium of the patio door frame is only 1.5mm thick, so I guess that I'll have to insert "rivnuts" into the frame. Or something. ( This sorta thing:

)

Apparently, rivnuts can be fitted without a special tool. ( Like so:

)

However, I've been trying to decide which metal the rivnuts should be made from. I've really no idea what I'm doing here. Rivnuts can be made from aluminium, but surely that's too weak for fixing a security lock? They can be zinc-plated steel like the one above but will that cause galvanic corrosion of aluminium? I don't know. They can also be stainless steel but isn't that even worse for galvanic corrosion of aluminium?

[Tim Watts]

Will they get wet? Dry joints don't corrode - or at least not at any appreciable rate.

[Dave Rove]

Not direct rain but possibly condensation in the early morning because it's a cold metal? I don't know. The vertical part of the aluminium door frame is a hollow section that appears to be open top and bottom, and thus exposed to the outside environment, but shielded from direct rain by the exterior door frame.

I'd be cutting a hole into that aluminium hollow section to insert the rivnut. (An alternative to a rivnut would be bolting right through the frame from inside to outside but I don't know how to secure the nut on the outside from being undone.)

[dennis]

If you are trying to stop them lifting the door out of its track and/or sliding then you can fit locks that the bolt goes into a hole in the door and the lock is screwed down through the aluminium into the sub frame.

[Dave Rove]

If I understand you correctly, you're suggesting putting the lock sideways on the external frame so that the lock's bolt pokes horizontally into the door? Unfortunately, the shape of the external frame doesn't really lend itself to that in my case:

[Nightjar]

I suspect he means this sort:

It bolts to the side of the frame and the pin at the back goes into a hole in the door.

Colin Bignell

[Dave Plowman (News)]

If the ally frame is only 1.5mm thick I'm not sure it's worth bothering with a lock. ;-)

You can buy a Silverline tool for rivnuts for not a lot (I've got one). It's quite hard work to use, but gives satisfactory results for the odd one or two, especially on the smaller sizes. If you were doing lots you'd want one with more leverage.

[Dave Rove]

I see. I'll get a couple of those then. Drat. I'd already opened the packets containing the other locks.

[Dave Rove]

That appears to be the thickness of the walls of the hollow section of the frame, which seems robust enough to form a rigid door, but does make it unsuitable for tapping a thread.

OK, I've decided to get a different type of lock now, but I'll bear that in mind. I did notice somebody mention cheap tools in the Amazon reviews for rivnuts, but said that they got better results by screwing a bolt through, then holding the bolt in place with one spanner while using another to tighten a nut down onto a couple of washers on the rivnut.

[Andy Burns]

The silverline tool is OK but no better than that, I could feel/hear the tool destroying itself as I set a handful of rivnuts, I might just be a ham-fisted gorilla but it's not the first time one of their tools has been worse for wear before its first job is completed - I tend to regard their products as cheap and almost disposable.

[Dave Plowman (News)]

The snag is you have to prevent the rivnut from turning - at least until it gets a grip. Really with the Silverline tool costing about 20 quid and with all the adaptors needed for the common sizes it's hardly worth the bother.

[Dave Plowman (News)]

I've used mine quite a bit and found it ok. You must be very strong if you've managed to destroy it - as you can easily 'feel' the rivnut compressing.

[Alan Braggins]

i) Any weaker than the frame? If someone can pull the nut out of the frame, it doesn't matter how strong its threads are. ii) You notice the bit in that video where he says you'll want the proper tool for a steel insert rivnet? (0:58) (But you can do modest sized steel ones the bodgy way if you have to.)

[Andy Burns]

Mine were stainless steel rivnuts, given it was holding a banister rail and that I'd never used them before, I might be guilty of over-tightening them "to be sure".

[newshound]

These are very good (and can be used in tight spaces)

I've also had problems with the £10-£15 "gripper" ones, but not yet felt the justification to spend £50 or more.

[Dave Plowman (News)]

Ah. It could well be you need a better tool for this. I've stuck to the mild steel type as supplied in the kit. But such a tool could be several times the price. I stick by my view that the Silverline is just fine for most occasional DIY, if used as intended.

[Dave Plowman (News)]

That looks like it could be useful - again for infrequent use.

[Vir Campestris]

I fitted one about half-an-hour ago. There's a thingy in the pack you put in the hole before you screw down the plate with three holes.

Andy