Thread: "Suction" on the stone?

I've held several classes in honing and I often let the students make a hundred or so passes on 8k and many of them get good suction and many of them don't, so although, for me, hyper sharp and smooth involves lots of 8K passes its not the only criteria.

A perfect bevel off the 4K has often been what I think is an important criteria.

Next a perfect stroke has consistently been demonstrated to me as another issue. Some students will do maybe 100 strokes and get no where, hand the stone to me and I'll have it sucking in 10-20 strokes, hand it back and soon it won't be sucking again.

It took me several years to perfect the stroke that I use and, as mentioned in the barbering textbooks, honing is a learned motor skill. I'm convinced of that at this point, so I feel that hundreds of strokes on 8k is good muscle memory.

Finally, its possible that the honing strategy of lessening pressure (and doing it correctly) has some effect as well. I'm not sure because I have always followed the concept (I don't know any different). But in summary if I were to finish with 50 strokes, 20 might have a little pressure, and 20 might have none. The last 10 might be no pressure, ultra slow perfect strokes as I take note of the final edge being applied to the razor. But I think it might be more accurate at this point to simply say I just hone with lessening pressure, ensuring its always equal on both sides.

Without getting overly technical if you think about the dynamics of what happens when you use pressure I think it may be possible to clear out the bevel area as the edge rises off the hone and create a mini-concave curve in the bevel that builds suction. Is this right? I really don't know. This is one of the secrets that was passed on to me.

But I don't think you should get too hung up on pressure/sucking. I can't say that sucking and sharpness have any direct correlation. It does though lead to a smoother shave.

Originally Posted by AFDavis11

Next a perfect stroke has consistently been demonstrated to me as another issue. Some students will do maybe 100 strokes and get no where, hand the stone to me and I'll have it sucking in 10-20 strokes, hand it back and soon it won't be sucking again.

I've noticed this as well - if I'm not careful, I tend to use less pressure on the return stroke.

Originally Posted by AFDavis11

Finally, its possible that the honing strategy of lessening pressure (and doing it correctly) has some effect as well. I'm not sure because I have always followed the concept (I don't know any different). But in summary if I were to finish with 50 strokes, 20 might have a little pressure, and 20 might have none. The last 10 might be no pressure, ultra slow perfect strokes as I take note of the final edge being applied to the razor. But I think it might be more accurate at this point to simply say I just hone with lessening pressure, ensuring its always equal on both sides.

This makes perfect sense to me as well - with lighter pressure, less and less metal is removed so the edge gets smoother and smoother - it just seemed that getting the edge so smooth that it "pops" when you lift off the hone would take thousands of strokes. Once I get to where I feel the suction on the hone, I try as hard as I can to only let the weight of the razor rest on the hone. I'll try to reduce pressure even more and and go slower on those strokes and see where it gets me in regards to sharpness.

Originally Posted by AFDavis11

Without getting overly technical if you think about the dynamics of what happens when you use pressure I think it may be possible to clear out the bevel area as the edge rises off the hone and create a mini-concave curve in the bevel that builds suction. Is this right? I really don't know. This is one of the secrets that was passed on to me.

I'm not sure on this - to me (not being a metallurgist, but with a bit of blacksmithing experience), it seems like using too much pressure would be more likely to shorten the bevel, but I can envision what you're describing as well.

Originally Posted by AFDavis11

But I don't think you should get too hung up on pressure/sucking. I can't say that sucking and sharpness have any direct correlation. It does though lead to a smoother shave.

It seems to me that if you have the edge smoothed to the point where it 'pops', you've gotten the bevel all the way to the edge and it'd have to be sharp. I'm not "hung up" on it, per se, but it seems to be (at least in my mind) a benchmark to show that you have a good bevel on the edge that will eventually get you a sharp, smooth edge - it's just finding that right point to say "ok, this is getting sharp enough, let me strop it out and check".

I'm going to fiddle with that idea on the Boker, I'll keep the Solingen as the primary shaver (since I've already tested it) until I'm sure the Boker is sorted out.

Sounds good. As another reference to bevel polishing, I hone on the 8k enough that turning the razor in a bright light will reflect enough light off the polished bevel to actually hurt my eyes when I roll it and get hit with the reflected light. It becomes a mirror like polish.

The fine line down the edge exists as the "fin", the sharp edge of the striations meeting each other.

I have achieved suction on the Chinese 12k but that isn't always a good thing especially when the suction is so great you can't move the razor anymore!

Originally Posted by ucliker

I have achieved suction on the Chinese 12k but that isn't always a good thing especially when the suction is so great you can't move the razor anymore!

Wow - that's extreme! I can't imagine you get a good edge with such suction?

Cheers
Ivo

ps - hope you are better after your running spill!

Nope when i get suction like that i no i went to far! then i have to start all over.
The Chinese 12k is a very slow cutting hone but like any hone it can screw an edge up really fast. the most strokes i do is around a 100 but i have done about 1000 before to see the differences.

Good points, all...thank you.

.... and I see why you all were saying that it's not a sure indicator of sharpness if you get suction on the stone, and why everyone said "get a microscope".

I was working on the Boker last night, and some review of my technique showed that the 'suction' I was getting was actually due to a bit of rotational pressure on the shank of the razor. The bevel was smooth, but it wasn't *sharp*. Through the 'scope, I was seeing some granularity at the edge of the bevel, which I thought was residue from the hone, but was actually a dull edge. More work on the 8k took that granularity off and left the bevel smooth all the way to the edge.

I don't have the whole edge in that shape yet, but the sections that *are* in that shape takes hair off my arm with no pressure using a shaving stroke. It doesn't take hair above the skin yet, pass a HHT, or feel "sticky" yet...but it'll get there, given time.

Again, I'd like to thank everyone for their encouragement and advice.

Excellent observations. Once you get the edge uniform, the only thing you have to worry about is developing a light touch to get the edge as fine as possible.

I'm not advocating that you do this, but this is where I use my 1K hone. To get the edge even, you are going to have to remove X amount of metal. Whether you do it in 50 strokes with a 1K stone or 400 strokes on a 4K stone, it has to come off. To me, doing fewer strokes on a coarser stone means you're less likely to mess up the edge by getting sloppy as you get tired.

Although it can seem like a waste of previous work to drop down in grit, it's not difficult to polish out coarser scratches and leave a smooth edge if you use the right grit progression. If you get the bevel right, you're less than 100 strokes from shave-ready on the Norton progression, if you do everything right.

But you can definitely get where you're going with the 4/8K, and you'll probably learn more by doing it that way right now.

Just my 2 cents,
Josh

G'morning, Josh -

Good ideas, and I think I may just try that. I know I put a LOT of strokes in on the 4k before I realized what was happening - it'd be nice to get it ("it" being any of my razors) to a shave-ready point in 100 or so strokes!!

I'm guessing that you're recommending making the bevel (all the way to the edge this time!) on the 1k, then progressively smoothing out the scratch pattern on the 4k/8k stones?