Yesterday, I Watched Kevin R. Cashen's Elements of Knife Design Form and Function. Well, doing some hand polishing a knife to refresh myself on design elements (along with his Heat Treating video for the same reason). today, i am doing the same thing with the same knife, it hit me. Now, this might be a me realization, and everyone realizes this or it might be something few realize or it might be something those with some experience forgingng eventually realize. ...Knives should not be perfectly machine flat down the entire blade...if they are forged, they should be flat at the Riccaso, but well, they should be straight but not flat. A flat knife, other than a kitchen knife, is heavy in the hand. A straight knife with a distal taper is light in the hand (unless you have a small, extremely wide blade).
Side notes: The only factory knives I have are kitchen knives, and I threw in that exception and the knife i have been working on as I just wanted to see how wide i could bevel a small blade. I like a step on the handle when it's a full tang as that step acts as a Rudamentry guard to lock your hand in place...also I am one of those guys with a really big hand, so my handles tend to be disproportionately big. However, for people who dont have a big hand, i have small little pieces of steel measured to 4 1/2 inches and smaller i use to size a handle.
For the purposes of balance and handling, the thickest part of a blade should be the ricasso. It is also the only part of the blade where the four planes, making the top and bottom and sides, should be completely parallel. After cleaning up the forging and shaping the tang, the first thing I do is layout the ricasso so that it is absolutely flat and parallel, so that all four corners of the ricasso read exactly the same with a set of calipers. Thus, I can use the ricasso to layout the rest of the knife with reliable straightness regardless of the tapers required. A surface plate and height gauge will become your best friends for this.
For this reason, I refer to the ricasso as “the foundation of the knife” as all others measures of straightness are relative to it. This is also why JS and MS judges will first look to the ricasso area before anyplace else, not only are around 70-80% of all failure level errors in this area, but how far off things may be elsewhere will be evident as compared to the foundation of the knife.
Here's a link to one of the pieces of paperwork that all my Basic Bladesmithing students receive. It's intentionally visually exaggerated to make the point...but I believe it's similar to what Kevin is talking about.
If not, then it's an alternate method to make a lot of things easier when assembling a knife, while still maintaining the distal tapers, and all the aspects those enhance. Some folks might be worried about having a "high spot" in a ricasso, but when done correctly, it is invisible to the eye, and most folks would need a micrometer to find/know it's there.
I stumbled upon this method when I was struggling with knives for my JS test way back in the early 90s.
It got me through my JS and MS tests. And is pretty much the method I use for all of my straight knives to this day. Hope it helps.
Ed Caffrey, ABS MS
"The Montana Bladesmith"
www.CaffreyKnives.net
