Thread: Hand Sanding A Blade, Redux

Reading the SRP Wiki is, truly, an education in itself. Lots of great stuff, and no matter where a guy begins, all roads lead to success. So, when I read the excellent article Hand Sanding A Blade, I failed to evaluate it with regard to my (then) current project -- restoring a fine 190+ year-old I.Barber 7/8" stub tail (and posts following). In this instance, where the author wrote: "Instead of circular sanding you could also speed up metal removal by sanding first from spine to edge, and then from heel to toe, and then from spine to edge again, but sanding from spine to edge is uncomfortable because the distance is so short" and, more to the point, where he writes and repeats "spine to edge... spine to edge."

I followed that mantra, with these horrifying results:



I say "horrifying", because by sanding from spine-to-edge, I completely lost the all-important "Line of Demarcation" between the spine and body of the blade. Why is this important? Why does it matter? Why? Because this "geographic" feature is what rests on the hone, creating the geometry that sets the angle for the blade-edge, and determines the quality of the initial bevel and the resulting sharpness obtained from the honing process.

I consulted other informational material in my possession, and found the following photograph in Bill Ellis' Straight Razor Restoration Guidelines (excerpted and included here, with the express written consent of its author):



It is vitally important to not sand from spine-to-edge and, instead, to be scrupulous in ensuring that one only sands from edge-to-spine (as the author's annotation clearly states). Had I done so, the spine edge of the I.Barber would still be crisp, the blade still clean and shiny, and I would have been able to set an even bevel and produce a "wicked sharp" cutting edge.

"If I could turn back the hands of Time..."

This is interesting information that lead me to pose a few questions:

1) When honing nice razors (like the one you pictured and restored above), many people use a layer of tape over the spine to prevent hone wear on the spine. If you were going to tape the spine, would the "horrific" "geometry" you mention above actually be an issue? I would venture that the tape, provided it was properly placed, would create proper geometry. By extension, wouldn't you be able to set a bevel that would produce a nice edge?

2) From the illustration, I fail to see the distinction between sanding from edge to spine compared to from spine to edge. Are you suggesting that one should start moving the sandpaper upwards from the edge, but stop short of the spine line in order to not disturb such line? The illustration seems to indicate that the sanding stroke is both up and down. Wouldn't a downstroke be from spine to edge?

3) There could be scenarios where the spine might need to be aggressively sanded and the spine line might need to be disturbed. For instance, what if you had deepish black pitting (devil's spit) along the spine?

Originally Posted by Bordee

This is interesting information that lead me to pose a few questions:

1) When honing nice razors (like the one you pictured and restored above), many people use a layer of tape over the spine to prevent hone wear on the spine. If you were going to tape the spine, would the "horrific" "geometry" you mention above actually be an issue? I would venture that the tape, provided it was properly placed, would create proper geometry. By extension, wouldn't you be able to set a bevel that would produce a nice edge?

If the spine edge is still extant -- sharp and clearly delineated, as in the leftmost photo of the original blade -- then a single layer of electrical tape will conform nicely to the profile, and the geometry will be stable (consistent) along its length. But, if the spine edge has been smoothed -- no longer sharp and clearly delineated, as in the rightmost photo -- then the geometry will vary along its length, making a consistent bevel at best a crap-shoot.

2) From the illustration, I fail to see the distinction between sanding from edge to spine compared to from spine to edge. Are you suggesting that one should start moving the sandpaper upwards from the edge, but stop short of the spine line in order to not disturb such line? The illustration seems to indicate that the sanding stroke is both up and down. Wouldn't a downstroke be from spine to edge?

The distinction is clear. Moreover, the author states emphatically: "Do not roll over the edge of the original grind." -- doing so (rolling over the edge) is what destroys the spine edge. In the accompanying photo, all strokes beginning at the blade edge end short of the original grind (spine edge); all strokes ending at the blade edge begin short of the original grind (spine edge). Protecting the original grind/spine edge is of paramount importance... unless you want to subsequently invest in a not-inexpensive regrind... something I would never consider doing to a 190+ year-old I.Barber blade.

3) There could be scenarios where the spine might need to be aggressively sanded and the spine line might need to be disturbed. For instance, what if you had deepish black pitting (devil's spit) along the spine?

If I had a blade with "deepish black pitting" along the spine, I would do what so many have done before me: Do what I could, and accept what I could not... and, at all costs, preserve the original grind/spine edge.

As it stands, now, my 190+ year-old I.Barber 7/8" stub-tail blade is little more than (at best?) a shiny paperweight.

Originally Posted by JBHoren

As it stands, now, my 190+ year-old I.Barber 7/8" stub-tail blade is little more than (at best?) a shiny paperweight.

This is the only part of what you've said that I disagree with...no need to toss such a nice blade aside and not give it use. Try using a couple of layers of tape when honing it...you may be surprised at what that may do. Although not ideal, it may just be the solution...I've seen many blades where tape can be your friend and still lead you to a fine shaver

Originally Posted by JBHoren

If the spine edge is still extant -- sharp and clearly delineated, as in the leftmost photo of the original blade -- then a single layer of electrical tape will conform nicely to the profile, and the geometry will be stable (consistent) along its length. But, if the spine edge has been smoothed -- no longer sharp and clearly delineated, as in the rightmost photo -- then the geometry will vary along its length, making a consistent bevel at best a crap-shoot.



The distinction is clear. Moreover, the author states emphatically: "Do not roll over the edge of the original grind." -- doing so (rolling over the edge) is what destroys the spine edge. In the accompanying photo, all strokes beginning at the blade edge end short of the original grind (spine edge); all strokes ending at the blade edge begin short of the original grind (spine edge). Protecting the original grind/spine edge is of paramount importance... unless you want to subsequently invest in a not-inexpensive regrind... something I would never consider doing to a 190+ year-old I.Barber blade.



If I had a blade with "deepish black pitting" along the spine, I would do what so many have done before me: Do what I could, and accept what I could not... and, at all costs, preserve the original grind/spine edge.

As it stands, now, my 190+ year-old I.Barber 7/8" stub-tail blade is little more than (at best?) a shiny paperweight.

Thanks for clarifying what it means to not "roll over the edge of the original blade" and how that entails stopping/starting just short of the spine edge. This is helpful information to remember when sanding.

Math usually solves these issues rather well...

On a 6/8 size razor one layer of electrical tape changes the Bevel angle about .67° not 1° but a little over 1/2 of 1°

Now there is a formula that with simple measurements gives you the ACTUAL bevel angle of your razor...


(2 * asin(.181 / (2 * .620)) * 180) / pi = 16.786646


the .181 was the width of the spine
the .620 was the height of the blade to the Hone line

Now measure the blade and find out the bevel angle, that will dispel your fear of ruining a razor... I doubt you changed the angle even 1° with all your sanding...

ps: this is a Google safe formula ie: just plug in your numbers and copy and paste it to google and hit search the answer will magically appear...

If that is a paperweight, I'll give you 10$ for it
If you hone with tape, you wouldn't notice this.
If you hone without tape, you'll get that line back. The demarcation is gone because it is ever so slightly rounded. Put it on the hone and it will be back. And as Glen said, from a honing pov, it doesn't change anything.

Now, in the interest of disclosure, it was me who wrote that document. I didn't have a razor like yours (I.e. with a wide spine), just the standard designs. However, the document says to sand the blade, not to sand the spine and the blade together, erasing the geometry. Btw, if you sand like that, the direction is edge to spine, and then when you pull back, edge to spine. Back and forth. Nowehere does it say that you sand OVER the spine demarcation line.

I would think that it is obvious that spine to edge, edge to spine refers to the direction. It doesn't tell you that you should sand away the spine itself. Just like a north-south route doesn't run from the north pole to the south pole.

Originally Posted by gssixgun

Math usually solves these issues rather well...

On a 6/8 size razor one layer of electrical tape changes the Bevel angle about .67° not 1° but a little over 1/2 of 1°

Now there is a formula that with simple measurements gives you the ACTUAL bevel angle of your razor...

(2 * asin(.181 / (2 * .620)) * 180) / pi = 16.786646

the .181 was the width of the spine
the .620 was the height of the blade to the Hone line

Now measure the blade and find out the bevel angle, that will dispel your fear of ruining a razor... I doubt you changed the angle even 1° with all your sanding...

ps: this is a Google safe formula ie: just plug in your numbers and copy and paste it to google and hit search the answer will magically appear...

As I see it, the issue is not the minute change in angle caused by rounding the spine edge; rather, it's that the new non-edge is no longer uniformly straight: it's now wavy. The spine edge on a new, or well taken-care-of razor, is straight for a practical reason -- not only for esthetic value -- it keeps the blade edge lying flat on the honing surface; this one doesn't... not anymore. And yes, the esthetics of a straight razor with a crisp spine edge are clearly superior; if not, why all the fuss about "hone wear"?

Originally Posted by Bruno

If that is a paperweight, I'll give you 10$ for it
If you hone with tape, you wouldn't notice this.
If you hone without tape, you'll get that line back. The demarcation is gone because it is ever so slightly rounded. Put it on the hone and it will be back. And as Glen said, from a honing pov, it doesn't change anything.

Now, in the interest of disclosure, it was me who wrote that document. I didn't have a razor like yours (I.e. with a wide spine), just the standard designs. However, the document says to sand the blade, not to sand the spine and the blade together, erasing the geometry. Btw, if you sand like that, the direction is edge to spine, and then when you pull back, edge to spine. Back and forth. Nowehere does it say that you sand OVER the spine demarcation line.

I would think that it is obvious that spine to edge, edge to spine refers to the direction. It doesn't tell you that you should sand away the spine itself. Just like a north-south route doesn't run from the north pole to the south pole.

There are any number of sayings in American English that are pertinent to this discussion; one which is well-known teaches that "An ounce of prevention is worth a pound of cure." Another says that "A picture is worth a thousand words." But my favorite is this one: "Never assume -- when you do, it makes an ass out of u and me."

As i see it, 1000-grit and higher sanding is only polishing, not shaping. Methinks shaping is something done way on down there 320 and below.

I use a wine cork.

and tape for honing.