Many do have plunge lines, but it’s a matter of taste. As with bolsters, it is an aesthetic that people either like or don’t.
I personally don’t like plunges lines (or full bolsters) on my kitchen knives. I think they look good and I appreciate them on other people’s knives, but it’s not me.
There are several reasons that I don’t use plunge lines or full bolsters. Primarily it’s because I prefer a full length distal taper from the butt of the handle to the tip. I also prefer a thin blade. I prefer the cutting edge to go all the way to the heel of the blade.
If you have plunge lines, you effectively create a full length bolster. You can have an angled plunge that allows the heel to extend below the plunge, which is nice- and allows for a sharpened edge through the heel.
You’ll notice that Japanese knives have no plunges and no bolsters. They tend to be thinner and lighter knives. European knives tend toward full bolsters and heavier blades.
The Japanese approach makes for a much quicker, much more accurate knife. The European style is much more robust.
I've done the angled "invisible" plunge line and it's tuff! I've made a bunch of hunting knives that I consider great with real world experience. Kitchen knives or I should say great kitchen knives in my humble opinion are way harder to make! Yes the thinner the better in my experience with kitchen knives.
I'm a newbie but what do you mean by "full" bolsters?
In the US and Europe, before Japanese patterned knives became accepted by trained chefs, full bolstered knives were considered the standard. It was the mark of quality.
In the not too distant past, the thinking was that the weight of the knife aided in chopping. Japanese knives changed that mode of thinking. A thinner, much sharper knife simply cuts better.
However, Japanese knives will not tolerate abuse. They aren’t the best choice for breaking down primal cuts of meat, or blocks of cheese, or butternut squash for example.
To me, kitchen knives represent the greatest opportunity for custom knifemakers. People who cook a lot and appreciate knives know what they want in a specific kitchen knife. Being able to offer knives in several styles really opens you up to a wide array of customers.
People who like European knives love the customs with plunge lines and / or metal bolsters. Japanese afficianados typically prefer plungeless. Why not offer both?
Thank you for the detailed response. Much appreciated. My understanding of what you call a full bolster was in my mind a integral bolster. I really do appreciate you taking the time to respond. I just have never seen many kitchen knives with plunge lines and never understood the why! I love your explanation. Thanks again. Your absolutely right why not offer both?
You won’t see any production kitchen knives with plunge lines because it would be too expensive. Production knives are stamped from sheets, which is why the bevels are only ground halfway up. They start with the thinnest material they can and leave some flat for stiffness.
Only very high end production knives have actual full flat grinds, and as you mentioned, integral bolsters because they are press-formed.
If you search around on this site, a number of makers do kitchen knives with plunges and they are beautiful.