Good day. I can tell you why the shower faucet problem hasn't been solved, but it is really technical/mechanical.
But, basically, the valve goes from 100% cold -> 50% cold/50% hot -> 100% hot. And the useful part of that is (depending on the temperature of your water heater) between 60%-40%. So, only 20% of the valve range. But, if you water heater was almost broken, you will be glad that you can go to 10% cold/90% hot... and so, that part of the valve needs to be there.
The problem is easy to solve, but the valve then becomes very much not simple. So, you have your normal handle, then you have an adjustment knob for your water heater temperature. Which makes everything complicated.
Maybe I should make a faucet, that behind the wall, is all electronic, and adjusts to the temperature of the hot/cold, and the pressure of each, and adjusts both so the simple faucet works as expected. I could do that. Probably only cost like $500.
What youre talking about is called a thermostatic mixing valve. they already exist you can pick one up at home depot for like a hundred bucks (and btw, i have one in my castle's shower and its awesome)
http://www.homedepot.com/p/Speakman-SentinelPro-Thermostatic-Pressure-Balance-Valve-with-Lever-Handle-in-Chrome-SM-5000/203713828
Why not faucets with settings (grooves, notches, whatever) that you can select and be done with it.
Because things change.
If someone goes and turns up the water heater temperature, they would need to go and adjust the faucet. There is also timing of shower; is the water heater full of hot water or empty?
And the biggest frustration as an installer, is that the non-technical minded have no idea how to adjust it. But, they try anyway and usually make a big mess of it.
My family and I have lived where we live for over seven years and have never adjusted the water heater temperature, simply because we have never had any reason to. But if, for whatever reason, we did have a reason, surely it would be so infrequent as to making an adjustment of the faucet a simple matter.
So it's like trying to solve a partial differential equation on the fly with mechanical controllers？
Ah.. the third term of the freshman year. Memories, memories. Although I could never found any use for them in real life. Did you?
If i were that good at maths, I would probably have solved this problem already instead of rant about it!
😉
The tap hole is round, it would make more sense if it was oval. Smoother transition from cold to hot. I guess they haven't figured that one out yet. :)
The tap hole is usually also about 1/8" in diameter. (3mm) We can only drill round holes. Machining an oval hole needs to use a smaller bit. That's getting small and intricate. Although CNC could probably do it just fine.
3d printing or laser cutting also comes to mind.
I do not know if sintered brass is strong enough (Laser sintered fast protoyping)
And laser cutting is not what you think. (damn, I am not thinking of an easy way to explain it, so I will just give up. A laser melts brass, not burn. Other metals that can be cut you use a gas that will react with the heat and oxidize the element.)
That's interesting. I figure this might be a cool problem for someone to crack. :) I'd really like to see an oval shaped tap hole some day.