The home made tool may not be able to unscrew a very tight nut because it is short. If you can weld a handle to it, it should work. But consider the time and parts/tool you have to spend on them, you are not really saving any money. The set of 14mm wrench is possibly $30 to $35 which does not include the valve holder wrench. I have a complete set as well as a simple home made 14mm wrench. The home made tool come in handy because it has an offset angle that reaches where the factory tool cannot.

David