Thread: Complicated (?) taping question

O.K., this has been bothering me for some time...

When a spine is taped, the hone encounters two very different surfaces -- the steel on the bevel, and the tape on the spine.

The abrasion resistance of the tape has to be much less than that of the steel bevel. Assuming equal pressure on both spine and bevel, the tape will wear more quickly, lowering the spine in relation to the bevel, and effectively changing the honing angle with respect to the bevel.

Specifically, this shallower angle will concentrate honing forces not on the very edge of the bevel, but closer to where the bevel meets the body of the blade. The more you hone, the more this effect would come into play. After the first stroke, you are no longer honing the edge, but somewhat higher on the bevel.

I know that in practice this doesn't occur. But it mystifies me why it does not. Wish I knew how to post a diagram, but maybe it is clear from the above.

Anybody got an answer?

Yeah, I think about honing a lot....

I read somewhere on one of these forums or other that changing the tape frequently, particularly after bevel setting on a coarse hone, is necessary.

The effect you describe must be evident, I wonder how much.

The first year I honed I used tape on all of the razors I sharpened because I was afraid of spine wear through inexperience. Now I only use tape on Damascus or decorated spines. When I did use tape I was used to the feel of a taped razor on the hone and I got good results. Utopian and I were talking one night and he mentioned changing tape when going from one grit to another. I had never thought of that but it is a good idea. OTOH, other than bevel setting I wasn't . and still don't, use a lot of pressure on the blade. If I use tape now I keep an eye on the tape. You can see when it is beginning to wear IME.

Originally Posted by pcb01

O.K., this has been bothering me for some time...

When a spine is taped, the hone encounters two very different surfaces -- the steel on the bevel, and the tape on the spine.

The abrasion resistance of the tape has to be much less than that of the steel bevel. Assuming equal pressure on both spine and bevel, the tape will wear more quickly, lowering the spine in relation to the bevel, and effectively changing the honing angle with respect to the bevel.

Specifically, this shallower angle will concentrate honing forces not on the very edge of the bevel, but closer to where the bevel meets the body of the blade. The more you hone, the more this effect would come into play. After the first stroke, you are no longer honing the edge, but somewhat higher on the bevel.

I know that in practice this doesn't occur. But it mystifies me why it does not. Wish I knew how to post a diagram, but maybe it is clear from the above.

Anybody got an answer?

Yeah, I think about honing a lot....

There is the answer besides what was already pointed out about changing the tape after either each grit or stage and of course after tape wear on the bevel set...

There has to be what is sometimes referred to as torque toward the edge, if this isn't present then all you are going to accomplish is wearing out the razor faster and not getting the best edge...

Don't mistake what I just said though this is very slight and gained through experience, the tape helps accomplish this, but even without tape it is there...
This is why people that are very good at honing leave very little hone wear on the razor when no tape is present, and beginners grind the spine up...Experiance teaches you to add a slight bit of torque toward the edge..



Note: to experienced honers try and forget what I just wrote it will mess you up for at least a few razors but trust me if you are honing and getting good edges and very little hone wear on the spine you are doing it

I understand about changing tape regularly, not honing on different grits, etc. My question isn't so much about practice, but theory. According to the logic in the OP, you'd have to change the tape after every stroke to keep the very edge of the bevel on the hone. (I know in practice tape works -- I use it often, and I know the bevel gets sharpened). My question is why does it work, when by that logic it should not.

Glen's observation is to the point. If you were to apply greater pressure to the edge than the spine (torque), then this might be enough to compensate for the edge's greater resistance to abrasion. Exactly how much pressure would overcome the differences in abrasion is an exercise in dynamic physics I'm incapable of. However, given the clearly great differences in steel v. tape it would have to be a generous amount of torque, I think.

Maybe very experienced honers, as Glen suggests, can generate such torque without lifting the spine and compromising the honing stroke. But tape is used by honers at all levels, and works with most if not all such honers. I personally don't think I use significantly greater pressure on the edge than the spine. Which leads me back to the original question. Why isn't the edge of the bevel being gradually canted away from the hone under such conditions?

Sorry -- but this question really has gotten into my head. If y'all tell me to go away and do something more productive with my brain, I promise not to take offense.

Originally Posted by pcb01

Why isn't the edge of the bevel being gradually canted away from the hone under such conditions?

It is, but when the tape is replaced it restores contact at the edge, and the extra wear at the back of the bevel, because of the canting, helps to ensure that the steel removal self-corrects the bevel by focusing the honing back at the edge.

I can't help but take a crack at this. The tape won't wear evenly across the spine. The leading edge of the tape will wear soonest and the most. The softer leading edge of the tape will allow the spine to maintain it's harder and dominant position thus keeping the honing along the same plane.

Originally Posted by gssixgun

There is the answer besides what was already pointed out about changing the tape after either each grit or stage and of course after tape wear on the bevel set...

There has to be what is sometimes refereed to as torque toward the edge, if this isn't present then all you are going to accomplish is wearing out the razor faster and not getting the best edge...

Don't mistake what I just said though this is very slight and gained through experience, the tape helps accomplish this, but even without tape it is there...
This is why people that are very good at honing leave very little hone wear on the razor when no tape is present, and beginners grind the spine up...Experiance teaches you to add a slight bit of torque toward the edge..



Note: to experienced honers try and forget what I just wrote it will mess you up for at least a few razors but trust me if you are honing and getting good edges and very little hone wear on the spine you are doing it

+1 Well said Glen! I agree completely!

Originally Posted by Utopian

It is, but when the tape is replaced it restores contact at the edge, and the extra wear at the back of the bevel, because of the canting, helps to ensure that the steel removal self-corrects the bevel by focusing the honing back at the edge.

Yes, when the tape is replaced it restores the geometry and refocuses the honing to the very edge of the bevel.

But, following that logic, doesn't this mean that for efficient honing, we should replace the tape very frequently and not, as I believe most of us do, when we get tape bunnies on the hone or see visible wear? And that the most efficient (if impractical) strategy would be to retape after every stroke?

Originally Posted by Obelisk

I can't help but take a crack at this. The tape won't wear evenly across the spine. The leading edge of the tape will wear soonest and the most. The softer leading edge of the tape will allow the spine to maintain it's harder and dominant position thus keeping the honing along the same plane.

I think I understand this. It introduces another variable, the amount of hone wear on the spine. On a new blade (depending on how the spine is shaped) only a very thin strip of the tape is involved. Abrasion force would be concentrated (on the tape) and result in fast wear. On a spine with much hone wear, a broader area of tape would be involved (the width of the wear on the spine), and would be at the same angle (relative to the central axis of the blade) as the bevel. Still seems to me that under those conditions the tape would wear relatively quickly compared to the steel bevel, and begin the canting process.