[pipecrafter]

You statement of:
"A knife is meant to cut, does that mean that if somebody cuts themselves with a kitchen knife they can sue the manufacturer?.......I think not."
Is short sighted. A knife is meant to cut. But if the government here passes laws on the manufacture of specific knives or knife parts, it is fiscally irresponsible for the manufacturer to continue making and selling those parts or kits in direct opposition to the law. Think about that for a minute. If the government tells you not to do something, and you do it anyway, what do YOU think is going to happen?

We're not talking "knives" in general. We're talking about one very specific product offering unique to one manufacturer. They even provide a center punched mark, so that IF you want to, oh I don't know, convert a perfectly legal knife to something that MIGHT be illegal in your SPECIFIC locality - totally without guidance from instructions or encouragement from the manufacturer... you can.

Rest assured, knifekits.com will continue selling sharp and pointy things for quite some time.

Other than that, the balisongs require nothing more than complex than a sharpening stone - which Knifekits.com sells, or you can stop by your local hardware store. It's Just Not That Hard. Neither is drilling a hole using a carbide drill bit. You can easily do it using a hand drill - or an antique brace if you so desire. Honestly, if you're paying $60 for the kit, another $12 for the carbide bit to make it fully functional is only secondary - and is useful for more than just one kit.

And beyond that, I strongly suggest you look at the laws in your country (UK, according to your profile block). You'll find that even owning a fully operational (automatically opening) DDR3BL will land you in prison for 3 months. This is part of the Offensive Weapons Act of 1959. In fact, depending on the specific judge, even a DDR3BL WITHOUT the spring could land you in jail - considering it can be opened by means of gravity or with a flick of the wrist.