Shapton ceramic 15k not polishing. Help!

So I've been using a Norton set and a shapton 15k to hone on. After I finish with the 8k and look at the edge under a loupe it's pretty scratch free. After I take it to the shapton however, I check the edge again and now it has scratch marks. It also Shaves better off the 8k. Now I've lapped it on 320 grit sand paper and that didn't do it. So I took my 1000k stone and rubbed it over the top to try to smooth it out. Didn't help. Did this all the way up to using the 8k on the stone and still the stone is leaving scratches and s more harsh edge than just the 8k. Any body have any advice on how to smooth this out?

I don't have the money to drop on a DMT 325 or a JNAT. Lol. I like the ideas but I can't afford them right now.

Don't use sandpaper unless it's wet/dry with very secure grit nor a 1k stone for lapping it, you are surely introducing stray coarse grit into the mix by doing this, no matter how well you think you are rinsing/cleaning the stone. Very fine synthetic stones can sometimes be tricky to get the most comfortable edges on. Try less strokes rather than more - if you have the edge in good shape at the 8k level it shouldn't take more than 5 laps minimum to 30 laps maximum to get a good finished edge. If you don't have a diamond plate for lapping, make sure you have good quality wet/dry emery cloth that won't shed grit for the lapping. That should get rid of your scratch problem.

eKretz said:

Don't use sandpaper unless it's wet/dry with very secure grit nor a 1k stone for lapping it, you are surely introducing stray coarse grit into the mix by doing this, no matter how well you think you are rinsing/cleaning the stone. Very fine synthetic stones can sometimes be tricky to get the most comfortable edges on. Try less strokes rather than more - if you have the edge in good shape at the 8k level it shouldn't take more than 5 laps minimum to 30 laps maximum to get a good finished edge. If you don't have a diamond plate for lapping, make sure you have good quality wet/dry emery cloth that won't shed grit for the lapping. That should get rid of your scratch problem.

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Well Done eKretz

I have seen the same thing with the shapton glass 16k. I could get a mirror polish on the shapton 8k with ease, but as soon as I go on the 16k I see scratches that the 8k didn't produce no matter how little pressure I use. I lap with a well worn DMT 325 for all my stones and get a smooth reflecting clean surface but I still have the same issue.

Now when playing/testing with my knives, since I know I can work more with them and not damage the edge, I noticed something. I would have almost no scratches after the 8k, I would get scratches when I first started using the 16k and the more I worked the scratches would go away again and get better. But that is with my knives and not my razor.

I still myself don't know what all this means yet, especially since on razors with the shapton 16k the more you work the more ragged the edge will get. ??? I really think it is a shapton problem and when doing a synthetic progression I have been tempted to go from my shapton 8k (1.84u) to my suehiro gokumyo 20k (0.5u) since it is almost the same jump as a 1k to 4k transition and also how fast the gokumyo cuts and how well it polishes.

Just at saying I know what your dealing with. It's also one of the reasons I'm transitioning to jnats. If anyone has any solutions I would like to hear them also.

Without seeing what you're seeing firsthand - it's hard to say one way or another.
Dressing the stone correctly is imperative - of course - that is a given. Any contaminting particles from anything that is coarser than the finisher will cause grief.

As noted, a 1µm finisher should not need more than 20 passes to get the job done. If you are doing a lot more than that, you might consider changing up the progression.


Once in a while, I get an email from someone who's first efforts on a 12k SS, 15/16k Shapton, etc is leaving scratches.
Most, but not all, of the time - the scratches in question are not from the finisher. They're from earlier work that was thought to have been wiped out. Looking at a bevel can be tricky, and sometimes a high mirror polish will mask the true story.
No one wants to believe that's the case - but that happens all the time.

Another cause is someone trying to slurry a high grit finisher - coarse chunks of stone pulled up by a 1k DMT or whatever will leave annoying marks on the bevel.
Lastly - it's no unusual for a synthetic stone to be either a little 'overbaked' or 'dried out' - so taking off 1-2mm can help resolve that problem. I had a Nani 12k like that, about 2mm into the stone the 'crusty' part was gone and all was good.

If your honing through the stone progression with one piece of tape on the spine. Try adding two more pieces of tape when you get to the 16K Shapton stone. Do no more than eight laps. Review your edge under magnification and see if you see a noticeable difference. Remove the tape and strop your razor. Perform a test shave and see if you like the edge better than the 8K edge honed with just one piece of tape.

I'll give all that a try. I have some lapping film from when I first started out. I believe I have some 30um and some 15um. Would these be safer to try lapping with, in correlation with removing a little extra from the shapton, to stay way from stray grit?

l try the adding tape at the end. However the last time I tried this the edge appeared more scratched up. You could see the line between where th 8k was visible and where the 15k was.

Just for experimentation purposes I would come of the 8k Norton using one piece of tape. Add two more and go to the Shapton. Remove the tape and strop the razor. Try a shave test and see how you like the results. If you want to experiment further give lapping film a try. The final arbitrator is going to be you the shaver and how you like to prepare your edges to your personal satisfaction.

There could also be the embarrassing part about using the wrong side of the stone. And on this I can not throw the first stone as I have used my shapton upside down for a year before finding out I was doing it wrong.

Gamma said:

They're from earlier work that was thought to have been wiped out.

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This. Irregular and borderline distinguishable scratch patterns will obscure much larger scratches from bevelers, even polishing and grinding wheels. Higher polish, especially synthetic polish, can bring these out, giving the impression that the edge is getting scratched on the finishing stone.

If the shave is worse off the 15k than the 8k, however, there are a few possibilities. The first is that your technique is such that you're having uncomfortable shaves off the higher grit synth. The second is that you do need to clean the stone up of grit. Scrub it with a fingernail brush under running water. I'd lean towards the first, frankly. A 4k JIS edge is a lot easier for most beginners to shave with than a 15k JIS. Right up until you're going for close ATG passes, where the 4k will fail spectacularly.

I figured the side with the writing all over it wasn't the side to hone on.......right? Lol

I've got a set of Shapton Ceramic Pro stones (1k,2k,5k,8k & 12k). At one stage I had the Shapton Glass 16k and 30k as well but sold them as I found that they didn't really add anything to the 12k edge from the Pro stone.

jKyro said:

I figured the side with the writing all over it wasn't the side to hone on.......right? Lol

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Actually, with most stones the side with the stamp is the sharpening side. But with some stones it really don't matter as long as they are smooth and flat, but this may be a special case. Lap the stamp side and see if you get better results.

You didn't mention what model the Shapton 15K you are having trouble is. Shapton Pro, Glass or the cheap little thin stone sold on ebay? I have a Shapton Pro 15K that can mirror polish an edge without much effort. I use it in a progression between the 8K and Suehiro G20.

I'm not the OP but it would not be the shapton glass since they make the 16k not a 15k. I was assuming the OP is talking about the Pro.

rlmnshvstr8 said:

I'm not the OP but it would not be the shapton glass since they make the 16k not a 15k. I was assuming the OP is talking about the Pro.

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I knew that, mind fart. Can't understand why the 15000 Shapton Pro is not performing for the OP. I love mine, its great! If it's a full price, retail stone, I would send it back right away and get a replacement.

It's the ceramic 15k in the yellow plastic holder/box. Pretty sure it's the pro.

jKyro said:

It's the ceramic 15k in the yellow plastic holder/box. Pretty sure it's the pro.

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Yes. That is the Shapton Traditional Pro

For me I find using less light strokes on finishers work better, I go from the 8K to 30-40 on he Apache Strata then 1/2 on the Sharpton 12K and only about 10-12 on the 16K but as I hone more I find I am getting better results stopping on the Apache. YMMV

I'm still at a loss to explain the Shapton Pro 12k/15k difference myself. It's the same exact stone as far as I can see, but some places call it 12k and some call it 15k. WTFIUWT?