Thread: Absolutely, positively the last word on spine taping

Originally Posted by singlewedge

I am not a math wiz, but let me see if this helps.

A razor is 5/8" high with a taper of 17 degrees. 3m electrical tape is 3.5 mil.

I think at that point you are only adding less that .001 degrees of tilt to the blade increasing the taper to 17.001 or something like that.

Is that what you are saying?

Edit: After posting your other posts appeared. A 5/8 razor = .625 removing a third of that .3/.625 = .48. .625-.48 = .145 which is equal to taking a 5/8" razor to between a 2/8 and 1/8. I would argue that the razor would be useless at about .25 of loss instead of .3 of loss.

According to your math, 0.48 is 1/3 of 0.625. Can't be bothered doing the math right now, but you may want to recalculate that one. 1/3 of .625 = 0.3 * 0.625.
Edit: That makes me sound like a tool, when in actual fact, I'm just drinking a lot.

I get the point of the original post though. What the actual angles are, is not important. You have to grind away a lot of steel from the edge in order to make any significant difference to the angle at the edge. I think you may of actually converted me with your math. I was always of the opinion that the tape must make a difference, but now it is obvious to me that the difference is miniscule.

Connor

If 14 and 20 were arbitrarily generated, then how can this be the last word?

PS nice sketches!

This may not contribute much to your calculations, but it looks like you have disregarded the tilt of the razor as it lays on the hone. If you were to put the spine of a razor onto a hone with the spine perpendicular to the hone, as you have drawn it, the edge of the blade would be in the air. To get the edge onto the hone, you have to tilt the razor by some angle. That will affect your "h" and "t" values, and I think it will also affect your "theta" values, since you will have to play with the bevel angle and the tilt angle. Also, as you continue to hone away the blade, the tilt angle will change.

I'm not sure what the easiest set of equations would be to incorporate the tilt, but it seems to me that the tilt angle is a function of "h" and "t."

EDIT: Actually, I think your theta is fine, since that is the bevel angle itself, not the razor angle of the whole razor.

I totally get what he is saying and I suppose that everyone here tapes for either edge refinement, getting closer to 18 degrees or to save the spine to maintain the 17 degree angle.

BTW the angle was had by Mr. Veerhoven. That is what he calculated with a laser protractor or something like that.

Originally Posted by holli4pirating

This may not contribute much to your calculations, but it looks like you have disregarded the tilt of the razor as it lays on the hone. If you were to put the spine of a razor onto a hone with the spine perpendicular to the hone, as you have drawn it, the edge of the blade would be in the air. To get the edge onto the hone, you have to tilt the razor by some angle. That will affect your "h" and "t" values, and I think it will also affect your "theta" values, since you will have to play with the bevel angle and the tilt angle. Also, as you continue to hone away the blade, the tilt angle will change.

I'm not sure what the easiest set of equations would be to incorporate the tilt, but it seems to me that the tilt angle is a function of "h" and "t."

EDIT: Actually, I think your theta is fine, since that is the bevel angle itself, not the razor angle of the whole razor.

The model can be kept simple by tilting the hone instead of the blade. Original math then holds true.

For a young fellow with a couple of razors and a long life ahead it would be a concern. For those of us who have RAD and a ton of razors our edges probably won't see the hone enough for wear to be an issue with or without tape. Thanks for the input though. Good to know that it isn't an issue for sure.

I think this might be either the third or fourth last word on taping that I have seen.

Here are a couple of points to consider.

First, when a third of the blade is gone from a razor, most grinds are going to be unusable anyway because you are going to be into a very thick part of the blade.

Second, let's say after 20-30 years of using your razor and honing it with tape you find that your razor with the beautiful worked spine now has too obtuse of an angle. Fine, at that point, you could easily make up for it by laying the razor flat on the hone, then slightly lifting the edge off of the hone, and doing a flattened bread-knifing stroke to grind away enough of the spine to restore the proper angle. From that point on subsequent honings would be done without tape, your razor would still have the proper angle, and you got to admire your beautiful worked spine for a good chunk of your life.

Originally Posted by Rosco

I get the point of the original post though. What the actual angles are, is not important. You have to grind away a lot of steel from the edge in order to make any significant difference to the angle at the edge. I think you may of actually converted me with your math. I was always of the opinion that the tape must make a difference, but now it is obvious to me that the difference is miniscule.
Connor

Before you get converted by my math, double-check it to make sure it's correct! These conclusions surprised me as much as they surprised you. Before this I had assumed that taping was bad because you were slowly altering the angle of the edge. Now I see it happens too slowly to matter.

Originally Posted by Utopian

I think this might be either the third or fourth last word on taping that I have seen.

That's the great thing about "last words," Utopian--if you don't like the current last word, just wait for the next one

Originally Posted by Utopian

First, when a third of the blade is gone from a razor, most grinds are going to be unusable anyway because you are going to be into a very thick part of the blade.

Second, let's say after 20-30 years of using your razor and honing it with tape you find that your razor with the beautiful worked spine now has too obtuse of an angle. Fine, at that point, you could easily make up for it by laying the razor flat on the hone, then slightly lifting the edge off of the hone, and doing a flattened bread-knifing stroke to grind away enough of the spine to restore the proper angle. From that point on subsequent honings would be done without tape, your razor would still have the proper angle, and you got to admire your beautiful worked spine for a good chunk of your life.

Yeah, that's what I'm thinking, too. Taping is a GOOD thing because it won't become a problem until you've honed away 1/3 of the razor, and by then you're going to need a re-grind anyway.

1/3 of the razor honed away would probably take a hundred years of daily use. However, as we well know, razors do survive for hundreds of years....

i think icedog already did this calculations once before...and someone else once used a CAD program to do it.

it is pretty interesting though...makes me wonder if i should or shouldnt tape my new dovo