What is the line running down the length of the blade?

[ProudMarineDad]

I tried a search in the forum but didn't see this addressed.
When you look at the blade in the light and tilt it you can see a "line" running along the length of the blade about 3/16" from the edge.
A friend told me he had heard this had something to do with the quenching process when the blade was manufactured or something and I was curious if anyone here could educate us on what that line is exactly?
If this is the wrong forum for this topic I apologize. I wasn't sure whether to post it here or the "Razors" forum.

Thanks

[kwlfca]

Pictures...?

[BobH]

I am thinking you might have a "bellied" blade. Can you feel a slight bulge along that line?

Bob

Viewed end on from the toe, looks something like this.

[ProudMarineDad]

Yes Bob I believe that is what it is. Is this normal? It's very pronounced on my Shutmate Tungsteel especially.

[cosperryan]

Some makers do it I believe to give strength to the blade to make up for the extreme hollow of the blade. I may be mistaken though but I thought I read that somewhere. I know my Dovo Pearlex has it.

[kwlfca]

Brian Brown just made one yesterday Instagram

Instagram

[pinklather]

PMD - I didn't know Shumate made a belly'd blade. I have a small Tungsteel (only 4/8 blade I keep *and* use). Its just hollow. I suspect if that's the way its made - that it would be one of the more rare birds for that company. I'll bet it shaves well.

[BobH]

Yes Bob I believe that is what it is. Is this normal? It's very pronounced on my Shutmate Tungsteel especially.

I don't know how normal it is. I think some makers use it on large, guessing again, 6/8 and up as a longitudinal strengthener for an extremely hollow blade. I don't know how common it is especially on American razors but was surprised to notice that my Genco Henry's X was bellied. I hadn't noticed it when I got it and honed it. I am guessing some are more pronounced than others.

Bob

[ProudMarineDad]

Thanks Bob. I see it in my Genco "Magnetic Steel" 5/8 razor as well as my Shumate "President" too. Actually I see it in all my Shumates but it is not as pronounced on the Tungsten, Vulcan, Peacemaker and Barber

[10Pups]

Is this not what they call double hollow? They use 2 different size wheels when they grind it. A large wheel makes the first cut and they come back with a smaller wheel near the spine leaving that belly for strength along the length of the blade. It gives the blade some slight flex while you use it.

I imagine it working to help keep an even pressure on the skin while making a pass. Allowing for slight changes in the angle of the blade by the user and helping it stay proper. Now that is just >me< thinking right now but I have read about this a few times before. Being a Dubl Duck user I have always thought that that name was descriptive and not just because of the 2 ducks on the tang :<0)