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 :gaah: 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.

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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....

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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 :rofl2::rofl2: but trust me if you are honing and getting good edges and very little hone wear on the spine you are doing it :D

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.

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Originally Posted by pcb01

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

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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.

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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 :rofl2::rofl2: but trust me if you are honing and getting good edges and very little hone wear on the spine you are doing it :D

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+1 Well said Glen! I agree completely!

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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.

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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?

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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.

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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.

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Originally Posted by pcb01

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?

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I guess I don't see a point into descending that far into the theoretical. Changing the tape just prior to moving up to each higher grit is sufficient to maintain the full plane of the bevel.

There would be a visual clue of this - I think. As the leading edge of the blade rises because of the new angle established by the wearing tape, the water in front of the blade would stop making the blade wave. In experienced hands, and I'm out of my league here, light torquing would maintain the blade wave. Experienced hands would know when there's too much torque and tape replacement is needed. Inexperienced hands would need to make tape changes more often.

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Originally Posted by Utopian

I guess I don't see a point into descending that far into the theoretical. Changing the tape just prior to moving up to each higher grit is sufficient to maintain the full plane of the bevel.

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I don't see that. If the spine (with tape) is wearing faster than the steel bevel, then the full bevel cannot be maintained (until/unless the tape is changed), or, as Glen and others suggest, the honer consciously or unconsciously torques the blade to correct it . Maybe the question is, (excluding torque for the moment) when, optimally, should the tape be changed?

The practical part, maybe I'm figuring, is that tape should be changed more frequently then most of us do (thanks, Obelisk). How do we know it's optimal with each change of grit? Changing after every stroke is impractical, obviously. Changing only when the tape is obviously worn (which is what I do if it precedes a change in grit) may mean that for some time I've been honing not the edge of the bevel, but somewhere between it and the body of the blade (i.e., the "shoulder" between the bevel and the (unbeveled) body).

The sweet, efficient spot must be somewhere between those extremes.

Or so it seems to me. But I may be losing it....

I've wandered the same thing. It seems like taping would lead to a curved bevel. :thinking: Great discussion.

Here is my strategy:

I repeatedly replace tape as needed during bevel setting. When I'm ready to move off of the 1k hone, I replace the tape and then do 10 more strokes on the 1k. Then I hone on the 2k for as long as I see fit. I replace the tape and do 10 more strokes on the 2k. Then I hone on the 3k for as long as I see fit. I replace the tape...

The same pattern continues all the way up. It works for me.

I am on board with Utopian...

I change tape when needed on the 1k, as soon as the shine is off the tape on the spine (I only use 3m 700)
I change tape when I move to the next stone normally a 2/3/4 k then again when I go to the 5/6/8 k

I always change tape before the finishers,

Now if I am using say the Naniwas I might not change tape from the 3-5 or from the 8-10... or the Shaptons between the 4-6 or the 8-16..

But honestly as soon as the shine is off the tape I change it regardless, you can see this and feel this when honing...

If you are going to use tape, keep it flat, straight, and change it often, if that sounds to complicated then take the tape off and ride the hones bareback :p
Keep this in mind though the same minute change principal that applies to the tape on the spine applies to the steel on the spine too :(

Utopian and Glen:

Thanks so much. I think you are instinctually doing what my thought experiment tells me I should be doing.

I typically hone on tape until a) the steel shines through or b) the aforementioned "tape bunnies" appear on the hone. Clearly too long. And I wonder why it takes so long to set a bevel!

Thanks again.

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Originally Posted by pcb01

Thanks so much. I think you are instinctually doing what my thought experiment tells me I should be doing.

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Well, actually I DID put some thought into it to arrive at that strategy. Glen probably did too!

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Originally Posted by pcb01

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.

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I am not a master honer by any stretch of the term, but I have given some thought to this myself. I do not think this to be true - I disagree on the premises. I rarely change tape during honing, at least compared to what seems to be the practice here. This does not apply to the bevel setting phase, on the coarse hones tape may need to be changed often, and it is evident there is wear on the tape pretty soon. However, after I hit the 3k hone I rarely will change the tape. I do not think the tape wears faster than the steel. I don't know why, perhaps the softer and more flexible structure of the tape help protect it, perhaps I somehow managed to get a small torque in the honing movement, perhaps the tape has a better glide and so doesn't wear as fast - when I take it off after polishing, it is very hard to see any honewear at all on the tape. I will sometimes check the tape under my microscope to see if I can spot any signs of wear on it, most of the times I cannot. I do not know why.


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Originally Posted by gssixgun

I change tape when needed on the 1k, as soon as the shine is off the tape on the spine (I only use 3m 700)

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Ah, never thought of this - what a simple solution. My tape is not high gloss, that may be why I am having problems detecting honewear. I'll get some new tape and see if that alters my experience.

I've wondered about the thinning of vinyl tape on spines ever since I started taping. After reading some responses, I did a search for titanium tape. Figured that would be harder than any blade and would hold up during honing. Unfortunately, the only titanium tape I could find is not adhesive backed and is used for some sort of joint pain relief. Like copper bracelets I suppose.

But, I did find S.S. adhesive tape and got to wondering. Isn't S.S. harder than razor steel (except for S.S. blades)? If this is the case, should it wear down slower than the edge during honing? Granted, it's pricey and seems to be too wide, but it is a thought. Just wondering, what do the experts think about this. Here's one of the links I found.
http://www.tapecase.com/p.2672.646/s...foil-tape.aspx

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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.

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I find myself resting my fingers _on the edge_, very lightly, and not touching the spine at all. So the spine "floats" on the hone, establishing the bevel angle. The edge -- with just a bit of pressure on it -- gets ground away.

8 strokes in one direction. Flip the razor. 8 strokes in the other direction . . .

And I refresh the tape often. I'm still working out the kinks -- color me "newbie".

Charles

I think Str8fencer is correct in his assertions.

I had an ebay razor with several severe nicks in the bevel, and after working it on a Naniwa 1k, I realized that the spline would be severly worn if I continued. So, I applied a layer of tape.

I changed the tape twice over 2-1/2 hours of honing using light pressure. I figured I'd change the tape whenever the sheen was lost on the tape, but it was like the Engerizer Bunny and just kept going and going.

Because I have crappy vision, I bought a regular microscope (the loupes and Carson didn't allow me to see anything). I don't know how much microscope you can get for $525, but whatever amount that is, that's what I have.

Under 100X on the microscope, I could detect no sign of a double bevel, not any sign of a rounded bevel. The scratch marks were straight and uniform over the entire bevel.

This suggest to me that Str8fencer is correct. The tape has a tendency to glide over the surface of the hone, rather than be abraided by it. Moreover, I think the tape has some flex in it, whereas steel does not. Thus, the flex allow the tape to resist abrassion also. Add both of these elements together, and the tape wears at a slower rate than the steel does.

Of course, I could be wrong regarding what's happening with the tape; but, I know what I'm seeing under the microscope is accurate. So, I think St8fencer is right on the mark on this.

Kent

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Originally Posted by klsmsn

Under 100X on the microscope, I could detect no sign of a double bevel, not any sign of a rounded bevel. The scratch marks were straight and uniform over the entire bevel.

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As the tape wears gradually, the transition from a taped to an untaped bevel would also be gradual. The geometry between both spine width extremes would never allow a rounded bevel and you would need to add tape to create a secondary bevel.

Thanks, Utopian, for "straighten me out" on straight geometry. I see your point.

This particular razor I'm working on still has a bit of nick on it, but I had some gun work to do, so wasn't able to finish completely setting the bevel yet.

I take it that in applying some new tape to continue, if there is any difference in thickness of the old tape from honing, versus the new tape, then I should see some indications of a second bevel. However, the wear on the old tape seemed insignificant, so I'm not sure I'd see any difference in the bevel at all. But, when I get to working on it, I plan to examine it under the microscope as I work on it.

If you want to see a secondary bevel, hone without tape or with one layer of tape until the bevel is fully being cut. Look at the bevel under the scope. Now add one or two layers of tape and hone 10 more strokes. If you look at the bevel again under the scope, you will see a small second bevel near the edge. This is because the additionally taped spine lifts the spine higher and this causes the part of the bevel distal to the edge to be lifted off of the hone, thereby concentrating the honing very near the edge.

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Originally Posted by Tolduonce

But, I did find S.S. adhesive tape and got to wondering. Isn't S.S. harder than razor steel (except for S.S. blades)? If this is the case, should it wear down slower than the edge during honing?

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No SS is not harder than razor steel especially if it is tape that cannot undergo a heat treatment to harden it but it would be harder than vinyl tape :)

Yes, Utopian, I understand that.

The question is not DO I want to see a second bevel; rather, it's WILL I see a second bevel if I apply new tape? Of course, I doubt this can really be answered until I do it and look.

I'm wondering if you have only .001"-.002" (mmm...perhaps more, hard to say) of wear on the tape, and then replace it, will a second bevel be observable?? I'm thinking probably not, but then, I don't know.

Kent

have never used tape just honed razor as is on surgical black arkansas which never really wore the spine just polished it now i'm wondering what are the benefits of using tape other than protecting the spine does it make for a better edge?? and make the razor shave better??

all the years i worked in the meat industry i steeled my knives at the same angle as i stoned them so the edge straightened properly and that's how i've always looked at sharpening a razor stoned at the same angle as it would be stropped so the edge is perfectly straight but i'm always open to new ideas and ways of doing things so i learn plus i'm a bit ocd and everything has to be perfect etc

Nik

Str8fencer opines the tape, being "softer" or "more flexible" is more resistant to hone wear than steel.

This doesn't make sense to me. How could a softer material be more resistant to abrasion that a harder substance, i.e., steel? And I don't see how a substance's flexibility could impart wear resistance either.

Can someone explain?