Thread: What is he Purpose of the Belly in straight razor?

Such type of grind meets not too seldom.

Everyone of my Solingen Hollows have some form of belly... you can see it in the refelction. I bet its to stiffen the steel

Hi Alex,
Can you comment on this style grind? Doesit have the edge stability of a wedge etc? This looks very curious, then you know what happens after curiosity.
Mike

Originally Posted by BKratchmer

As I understand it, this was left by some manufacturers to reinforce the bevel, thereby giving you the flexibility and ease of honing of a hollowed blade, but the longer-lasting edge of a stiffer blade.

yepers
for that extra hollow if you ran a blad that thickness over the whole hollow(no belly) it woudl be like tringto shave with foil
way too much flex

i made one that was not good for shaving as the flat before the edge was .004 over about 3/8 of the blade height too much flex to get any work done

a stiffer edge would have worked fine but would stil have that nice flex

My opinion, this hollow was made to give flexibility to an edge . It is well felt on wedge blade (Turner razor).

I consider this grind different from a bellied hollow. The belly of a hollow grind is a "stabilizing piece", like the "double shoulder" but horizontal. The grind posted here is a sort of "modified wedge", modified to give more flexibility and maybe a particular appeal. Just my reading of it.

This is a full hollow blade ground from a wedge blade blank. With modern razors the grind of the blade is determined by the forging of the intended grind into a die set spacifically made for that grind. When done this way the blank looks remarkably like a straight razor and the finish grind is all they have to do. Several companies opted to stay with a more traditional method and just hollow out a strip extending from the shoulder down anywhere from 50% to 85% of the blade width. If they grind deep and only use a set of wheels large enouth for about 50% of the width of the blank it looks exagerated like this. They do this with a small double wheel setup after the basic grind is done on the blade blank. There were a few companies that made their hollow ground razors like this presumably to make the edge stiffer.

I'm going to suggest a few thoughts on this matter for others to 'digest' and comment upon if they like.

I will start by indicating the obvious. A razor is just another tool. Tools are given different form(s) to match their function. Witness the different forms of the following: scissors, garden pruners, axes, adzes knives, swords, scalpels, arrowheads, woodworking tools and so forth. You will not find a slavish adherence to a straight form when a curved one will serve better for whatever reason.

If you go back far enough in time, razors had very rounded blades. This was never a problem, neither to use, nor to keep sharp. But mankind was a bit more casual about the tolerances back then. From what I read on the razor forums, one would think that most of the modern straight razor users are totally paniced by a hones that are not flat to within a tenth of a millimeter. Likewise the fearful attitude about curved edges and how to sharpen them correctly. I come from a woodworker's background and I do not find the same 'fear' of curved edges in that community. Those of you who are into knifemaking will also find absolutely no panic concerning either the sharpening or usage of curved edges in that group. So why in the straight razor commmunity?

Do, please, cast your mind(s) back to the time before the existance of safety razor with disposable (or exchangeable) blades. the straight razor was used for everything. When I employ the word 'everything' I am referring not only to shaving of the face, but also various other parts of the body, be it for cosmetic or medical uses.

The tendency towards totally straight edges on straight razors seems to have accelerated with the coming of mass production methods. We can especially thank King Camp Gillette for some of this, but even decades before then, with the introduction of 'safety razors' with removable or replaceable blades, the big tendency was to making straight edges. From a production point of view there is much to recommend this. Now, in a blade of short length (as in a safety razor), this is not such a bad compromise. Once the blade is longer, however, a totally straight blade in not necessarily the best form to use.

Now a curved blade has much to recommend it when used for shaving the face (under the chin, etc), but really comes into its own when one has to deal with other parts of the body. I'm going to present myself as a good example of this. I had a rash on my chest last year that required that I shave the hair along my sternum during the course of my treatment. For that task, nothing was better than my old Jaques LeCoultre Frameback, a razor with a most pronounced belly on its blade. That deeply-curved blade could reach down to 'scoop out' the hair within the hollow of the sternum without any trouble. I tried that same thing once with a flatter straight razor. It did not do the job at all well and I ended up nicking myself in the bargain. Even twin-blade disposables with their short blades did not reach down into that area as well as the old, curved frameback.

Now to be fair, there is also nothing inherently wrong with a staight razor having a totally flat blade edge, but there also isn't anything totally 'right' about it, either.

As a final observation, I note that hollow grinding a razor with a curved edge is fairly simple with either (A) a slow moving wet grindstone or (B) the double-wheel grinder developed expressly for that purpose in the industry. Once you move to flat sanding belts or surface grinders it becomes much more attractive to adopt a flat blade profile, simply to fit the production process to the limitations of the machine(s).

OK, I'm talked out.

- Ignatz

Originally Posted by manah

Such type of grind meets not too seldom.

second blade doesn't have Belly . diamond edge

this is the clear picture of the belly.
Picture from classicshaving .com

I think the advocates for added stiffness must be right. I recall reading on the forums that a full hollow would flex on a shavers cheek and I found that hard to believe until I shaved with some large flexy full hollows. They definitely do flex and that belly probably keeps them from being like Butch said, shaving with a piece of tin foil.

What John pointed out about the dies and the double wheel can be seen in the videos of TI and either Boker or maybe it is Dovo making razors.