Thread: Blademeisters: Bellied Hollow?

This question is for those who forge and grind razors, you know who you are
Have you made razors with a bellied hollow grind? Does it require much more in resources, time, skill? What are some benefits and/or caveats to making a blade with a bellied hollow grind, from the maker's point of view?

Thanks for reading.

Originally Posted by bassguy

This question is for those who forge and grind razors, you know who you are
Have you made razors with a bellied hollow grind? Does it require much more in resources, time, skill? What are some benefits and/or caveats to making a blade with a bellied hollow grind, from the maker's point of view?

Thanks for reading.

What exactly is a bellied hollow grind? Don't they all have a tiny bit of a belly?

I don't know, I have only seen a few razors that have an obvious belly, maybe they all do.
I'm going off this chart here:

Here is my incomplete answer, with my tools and experience it is exponentially harder to grind a hollow that deviates from the shape of the contact wheel/grinding wheel.



Charlie

Originally Posted by spazola

Here is my incomplete answer, with my tools and experience it is exponentially harder to grind a hollow that deviates from the shape of the contact wheel/grinding wheel.



Charlie

I agree. It's hard enough to do it properly with a more wedge-type grind.

I guess that's what I'd call a double hollow ground blade. Grind it once with a bigger radius wheel, say maybe an 8" or 10", then grind out between the spine and lower part of the blade with a 4" or 6" wheel.

That's how I would do it. Would I actually try it? Maybe someday, but I agree with Joe and Charlie. I haven't tackled full hollows yet, as those are an order of difficulty above simple quarter and half hollows. Something like this would be very tough to do well.

The old-time razor makers did their hollow grinding on machines that had a wheel on either side of the blade and a steady stream of water to cool the steel. A setup like that makes this style of grind a little less daunting.

Josh

On those old full hollows with that belly you can feel them with your fingertips. I am wondering if the temper of the steel, the quality, is changed at all when you find one with hone wear to the extent that it is into that belly portion ?

Originally Posted by JimmyHAD

I am wondering if the temper of the steel, the quality, is changed at all when you find one with hone wear to the extent that it is into that belly portion ?

Good question. Is steel like a cake in that the outside cooks or tempers faster than the soft moist insides?

Also, what do current razor makers use to grind blades if it isn't water cooled double wheels?

The way in which full hollows replaced the wedge historically indicated to me that making hollows was easier, but I suppose only if you have the right equipment?

Interesting.

Originally Posted by bassguy

Good question. Is steel like a cake in that the outside cooks or tempers faster than the soft moist insides?

Also, what do current razor makers use to grind blades if it isn't water cooled double wheels?

The way in which full hollows replaced the wedge historically indicated to me that making hollows was easier, but I suppose only if you have the right equipment?

Interesting.

If you look through the video sub forum you'll find a vid of the workman at Theirs-Issard doing the hollow grind thing on the special opposing wheels. There is also a vid of Dovo and IIRC one of the Boker factory. I don't remember if those show that procedure but they very well may. I think the custom makers use belt grinders with various sized wheels. There is also a vid of Mastro Livi doing his thing that is very interesting.

the "soft center" would be more from bad quench not from botched temper

some steels are shallow hardening (but still more then and 1/8 inch deep ) when done right
when you temper you may have the blade at 3-400f for 2 ours of more (that will evenly heat any blade you got )

i could grind and leave a belly but its more like a part way unfinished blade to me as i liek a nice smooth even grind from spine to edge

and yes its done by startign with say a 10 inch wheel then step doen to a 6 then 4 and 2 if you didnt clean up the bellies between the wheels you would have a ridge for each when that you "stepped" down to the bigger the difference in wheel size the wider the "speed bump" thats why the production houses have so many different wheel sizes