I'm not talking about a hex key that extends in length but one where it can collapse in on itself to increase in size.
I did some digging online but all I could find was a patent from a company called TeleHex but it kind of sounds like they came and went in the mid 2000s. They're website doesn't seem to exist.
I feel like it could save space in my pocket compared to a typical hex key set or a multibit.
I was hoping I could at least find a bootleg version on Ali Express.
Interesting idea, but I think it would suffer from being too weak structurally to be of much use. Each consecutive size would have to slide in and out and that design would cause trouble with maintaining rigidity.
However, if you would find one let me know. I would likely buy it too.
This is a solved issue. Use a bit set to have the different heads you need to fit on one driver. You can get ones that store the bits inside the driver.
Any telescopic mechanism is going to have a hollow centre and be weaker and prone to deforming. Larger hex keys are used to deliver more torque, making them hollows defeats the purpose of having a larger key, and small bolt and hex key should have been used to save weight and cost (or the same size to standardised the tooling).
Do you think the hollow core would make that much of a difference? The head of the key would still be solid and the depth required for each different size likely wouldn't account to much. There would probably maybe half an inch at the opposite end from the head. If someone used a t like design, with the top bit being where the grip and hollow portion are, I imagine that would likely cut down a bit on torque exposed directly to the hollow section.
I think this is a great idea! I guess strength might be the biggest issue? The metal would have to be layered really thin to fit all sizes, while being able to withstand strong rotational force. Although all the smaller sizes would fill the gap I'm not sure it would work.
Making and testing this idea would be a good YouTube video, maybe send this as a suggestion to some engineering YouTubers?
Telehex failed (I guess they've been trying to raise money on Kickstarter since at least 2015) because it offers no real advantage over a regular folding allen key with interchangeable heads. it's only good for 3, 4, 5 & 6mm heads, so you're paying an absurd amount of money for something that you could replace with one of these for a lot less money in the exact same form factor. plus, you're introducing multiple possible points of failure; there's no way a Telehex would survive as many uses as something significantly cheaper. same reason the universal socket didn't stick around
Depending on what you're using it for, your best bet might be a compact set like this or this.
There are various types of universal "female" style wrenches, but nothing I've ever seen for the "male" type that requires different bits. A set with integrated bit storage is probably as small as you're going to get.