wi

Need a little expert advice.

I have an Ebay special I am trying to hone and it is giving me a little trouble. Most of the blade is 4000 sharp, but this one spot just doesn't seem to want to hone up. Under the microscope (this is my judge of sharp) he whole edge is straight except for about 3/16 of an inch where there are several microscopic nicks, and what appears to be a microscopic hole through the edge. Since this has been the problem spot I have given it about a couple of hundred strokes on the 4000 with some pressure yet I see no substantive change in this one area. I am at this point assuming I need to step down to a more coarse hone.

Now the question, given the following choices what would you hone or step to to get the edge to come up?

hard white Arkansas
medium grey Arkansas
coarse aluminum oxide stone
stick it out on the 4000

It being Christmas and me being tapped I don't want to buy anything if I don't absolutly have to.

Could that portion of the bevel be shorter and not getting into contact with the hone?

good thought, I had to check, but it is contacting the hone.

I don't think a few hunderd strokes on 4K would fail to have a substansive change. Where is this portion of the edge? Towards the point or the heel?

If you think your honing ok and the spine is not wider or narrower at the point in question I would lap the hone, flip it around and continue on 4K, but I"m very concerned about this lack of change and what is happening to the sections that are changing in the process.

Are you using an X pattern?

Yea I'm worried about serious overhoning too but I am watching for it and while the rest of the edge is "keen" TNT this one area is still dull. I am wondering if it was banged at this point or something. The area is near the point so I will have to be a little more critical of my honing stroke.

Unless this is a particularly valuable blade I'd be tempted to put it on the 1k sandpaper for a bit, and try to work past this area.

On the point huh? Are you using pressure? 1K might be a good idea, but I'd do a little more diagnosis first.

Near the point about 8 to 10mm back. I use some pressure, not much, maybe three blade weights worth, not just letting the weight of the blade slide along but adding a tiny bit to it. I use the x-pattern with the heel leading a bit.

The microscopic hole is troubling to me. I think you may have a portion of the blade that either was subject to poor heat treatment or it was a bad spot in the steel to begin with and this does happen from time to time. You have a couple of choices. If it's not in a critical area and it's not bent or out of line, just ignore it. If you're compelled to make the edge perfect, you're going to have to grind back past that spot and that means a coarser stone than any of the above. A diamond extra fine like a DMT would do it. If you don't use something like that 1200 grit stone, you're going to be honing for a long time. Get aggressive and pull the edge back. Also, check the spine and just between the spine and the thickest part of the blade to see if there are any other troubling spots. If there are, it may be telling you that the steel is spongy and you may pull back the edge only to find another trouble spot. Interesting problem and I'd love to hear the resolution.

I agree that a more aggressive approach is needed here. Usually when I get a portion of a blade that won't get sharp it means that it's not making as much contact with the hone.

Have you tried the magic marker bevel test? Use a magic marker on the bevel, then do a couple of strokes on a barber hone. The marker will probably still be on the troublesome spot.

Usually what's happening is that the bevel isn't quite right and you're varying your stroke just a bit and hitting this trouble area just once every 10 strokes or so. It looks like it's getting ground but really isn't.

I would tape the spine and do a few hundred laps on 1000-grit sandpaper to wear the rest of the bevel down to the same level as this portion. Then your even strokes will hit the entire bevel at once.

It's possible that the steel is just bad in that area, but I think it's more likely that there's just some funkiness with the bevel. I've seen bevels that needed hundreds of strokes on a 1000-grit stone, so it doesn't surprise me that a few hundred 4K strokes didn't do the trick.

Good luck,
Josh