Thread: Why 2 grinds?

Is there any reason why a razor has two grinds on the same blade? The one im messing with now has a wedge and the other half is a half hollow. I was just wondering why they did that?

Pics????


This would help because what I am seeing in my mind ATM is a Microtome

like this thread???


http://straightrazorpalace.com/works...microtome.html

Razors are hard for me to get a good picture of lol. It does look like that one in the thread.

What you have there is a microtome, not a razor.

From the wiki

Single and double grinds
One of the simplest ways to remove metal from the sides of the blade is by contact to a grinding wheel, which carves out a circular segment resulting in a profile similar to this
However, more hollowing is easier to achieve with double grinding, carving out two overlapping circular segments. The resulting profile is characterized by a belly in between these segments similar to this

Originally Posted by HNSB

What you have there is a microtome, not a razor.

Which can be used as a razor.

Thanks guys. Sure took a nice slice out of my thumb while sanding.

Sharpening these is a bit different also, if you want to keep the correct bevel profile...

There are few different schools of thought as to the "correct" way

10/1
7/1
5/1
3/1
this refers to strokes on the flat side compared to the bevel side
you can also use a variable progression such as start with 10/1 at the bevel set and work you way down to the 3/1 on the finishers

Some people like the 5/2 Japanese style honing on these, which is 5 back and forth strokes on the flat side then 2 back honing strokes on the bevel side...

As you can see there is much debate on how to hone them and even how to shave them or if to shave them...

Personally on the one I built I used the "Variable Progression" and I have never ever seen an edge develop so fast, and so sharp on any other razor...

From what I have gathered, the grinds have to do with the purpose of the tool (here I mean "the grinds" as in western ground, Japanese ground, or microtomb ground). Western razors are designed to be used with either side to the face, Japanese one side, and microtombs are to cut thin segments of samples for lab purposes.

Single or double (or more) ground on Western razors seems to be related to whatever the maker finds the most successful. On the Livi DVD you can see him doing multiple grinds to each side. I believe there was a thread where a member visited Bob Allman, and they talked about using various sized wheels to do various grinds as well. I would assume there were similar variations in the making of vintage razors as grind technology and grind popularity both changed.

Originally Posted by jasp

From the wiki

Single and double grinds
One of the simplest ways to remove metal from the sides of the blade is by contact to a grinding wheel, which carves out a circular segment resulting in a profile similar to this
However, more hollowing is easier to achieve with double grinding, carving out two overlapping circular segments. The resulting profile is characterized by a belly in between these segments similar to this

I still cannot wrap my head around this. In my mind I think of them using two grinding wheels, one on each side as opposed to one side first and then the other lol. Can someone break down the difference for an idiot.