trouble with 50/80 grit stones.

[Roman]

hello guys (girls).

I am using WE for about a years and half mostly for repair and reprofing. I am setting primary bevel at 26-30 depending on steel. To maintain the edge I am putting micro-bevel using sharpmaker, which I use since 2005. I am using 10x Bausch&Lomb eye loupe as a visual aid.
My primary carry is Spyderco Forum Native with S110V. At the beginning reprofiling was just a piece of cake – fast, than 100 grit stones broke in and the last time I reprofiled the knife it took me more that an hour. Due to being not really patient person I started to think about 50/80 grit stones. I found a thread
https://knife.wickededgeusa.com/forum/14-abrasives/7949-who-uses-50-and-80-ultra-extra-coarse-stones
and concluded that things look not bad and I should try. Fortunately one of my friends has them and offered to try his, but he commented about very deep scratches.
About a month ago stones arrived and finally couple days ago I found time to try. The first impression: these stones are really super coarse – look almost like asphalt.
First cheap pakistani knife – a copy of buck 110, purchased about 20 years ago, when I didn’t know any better and $10 knife was expensive. Ken advised me to try only 80 grit first. I reprofiled it to 15 degrees per side and after 1000 grit stone edges looked acceptable for me. Than I repeat the same but started with 50 grit and finish on 1000. Still looks good.
The second test object was my Spyderco beater Native with S30V. The knife was used by me and abused by couple other people for 9 years. Without wasting time I started with 50 grit and finish with 1000. I certainly could see some scratches, I can live with. But in addition I saw two micro-chips. I wasn’t sure about a nature of these chips. Are they due to my technique, grit or steel issues. When I bought this Native some makers including Spyderco and BM experienced some issues with heat-treatment of S30V. This knife also was chipping, but after few reprofiling it became better.
Step 3 was my primary EDC S110V Native. Starting 50 grit with light pressure until burr is created. Than switch to lower grits and making about 100 strokes per side with progression up to 1200/1600.
When I looked at the edge using my 10x eye loupe I was stunned: almost entire edge had micro -chip. Of cause I fixed the edge, but extremely hesitant to use 50/80 grits again.
I am wondering if anybody experienced the same. Possibly it will get better after brake-in, but how long it will take? Should I get something like steel plate and grind it with both grits for an hour each to make stones usable on hard steels?
Any thoughts or/and advises will be appreciated.

[Zamfir]

Biggest advise I could give you is to not apex at this low grit. throw some sharpie on it and go until most of the work is done and just a sliver of sharpie is still visible. Then progress down your grits and apex at a much higher grit. On a good knife that may chip due to its hardness or whatnot I will wait until 400 or 600 to apex. I still do not have much of a feel for it, but after some experience I am starting to know when to switch over and start to apex. If you apex at that low grit you are gouging the heck out of the apex and have to grind it all away any how in order to remove the scratches. So it is a give and take I guess. Just my 2cents. I will be giving my 50/80 a whirl this week on some really bad kitchen knives to see how they work. I have not used mine yet. I hope someone else will chime in here about this with some experience!

[Geocyclist]

I would add:
1. These stones need breaking in like any others.
2. Start with 100 diamonds. If they are not making enough progress then drop down to 80 then 50.

Even on first time sharpening with a re-profile, the 100’s are enough. It is slower of course, but slow has it advantages. With a re-profile I want to make sure the bevel is even side to side. Using 100’s doesn’t take too much off at one time.

[Roman]

Gents,
Thank you for your thoughts. All of these make sense. Still any idea how long it can take to break-in 50/80 grit diamond. I understand, there is no magic number. Grade of steel, amount of removed material, technique will affect this number. I just would like to figure out, if I should keep these stones or send them back. As is I consider them not to be useful for me at all. 100 grit is kind of slow, but this still better than damaged edge, which I need to file off and than go back to 100 grit and spend even more time.

[James Kennedy]

Biggest advise I could give you is to not apex at this low grit. !

I am not sure what you mean. Are you saying that for lower grits you should change the angle so the stone does not touch the edge? Sorry I am just a beginner with sharpening.

[Zamfir]

I used my 50/80 grit stones last night on grandmas prison shank. Lol. Ill post a picture later. No you do not change the angle. Cover the edge with Sharpie then file away with the course grit and stop before you create a but. Then go to a higher grit and work some more. Try and apex with 400 or 600. I ended up apexing with the 80 on some parts of blade. What I ended up doing is just went down to 400 and made sure to apex the whole edge. Then destressed the entire edge with the 80p grit stone then apexed again with 4p0 and worked till the end.

[Roman]

Zamfir,
Thank you for help and thoughts.
Usually I an disstressing the edge with 3-4 passes of 600 stone. When all marker is removed, still a long way to go to create an apex, especially S110V. This would make difficult to stop before apex because the only way for me to see it – is creating a burr. I didn’t see a problem using 50 grit to create a burr on cheap and soft old pakistani knife. I want to redo both of my Natives S30V and S110V using 80 grit. Friday looks like a good day for this.

[Zamfir]

Just used the 80 again today. So if you are distressing that much. Go ahead and burr with the 80. Then keep going up in grit. Once I hit 4400. I lightly distressed the edge again with the 1000 stone. Just 2 passes. The apexed with 400 and finished progression. Helped a lot. Wit as has of shape my relatives knifes are in I am now starting them all with the 50/80 and doing it this way. Saved me lots of time!

[Roman]

Are you distressing before sharpening and than again after 400 grit or once after 400?

[Zamfir]

If I am starting at a really low grit I will wait till I hit the 400s. Then distress with the 1K stones, re-apex at 400 then continue. This is for a user mind you. If I was doing my zdp189 sypedrco I would never touch them with anything lower than 400 If I could help it. These knifes I am hitting with the really low grit are for total re-profile on cheaper kitchen knifes..although I did it with some Whoutchoff Tridents and Henkles today and it worked out ok with them. The first time I used these 50/80 stones yesterday they were exactly as you said..just like rubbing on concrete. But I rubbed the crap out of that old toothpck of a 50 year old Cutco. Today they sure are rough..as they should be..but they were not as crazy as they were yesterday. Maybe just the different steel or they got broke in a little. I totally re-profiled 12 knifes in the last 3 days. I started to really warm up to the 50/80 grit stones for these kitchen knifes that have been totally abused and needed a total overhaul. The biggest thing people worry about is how big of a groove you are making on the apex with these low stones. But many of these people are us fellow knife nerds that look at our stuff under a microscope and such.. But for 90% of the other people do not care. I think by the time I get the knife honed down and apexed with 50, then 80, then 100, then 200, then 400, then distress the edge lightly and re-apex with the 400, and work through the 1K, the apex is Jim Dandy. These are workin knifes and I am still more than likely putting more work than needed into them. But, it is for a Christmas Present so I put in the time and chat with the family while I am doing it. Learning a lot every time I do another knife. the more you practice the more you just get a feel for when things are about to happen..like —“ohhhh it is almost to apex” then you can switch to a higher grit.. But that will only come with time and practice! Until then..burr..burr..burr…That is what I still have to do sometimes if I am not familiar with a knife. New set of family now..Another set of 12 er so knifes in the next couple of days. At least a couple will be fun nice knifes..By Brother has some nice folders I am excited to get my hands on.

[Roman]

I started to like your idea distressing the edge right before 400. It make a lot of sense, especially if you starting with such coarse stones like 50/80 and creating like in my case micro serration on the edge. I certainly will try this tomorrow.
Merry Christmas to you and your family.

[Roman]

Today I had very unsuccessful day 🙁 . I started with about 300 strokes of 50 grit on my pakistani knife, just to brake in stones a little more and check, if I notice any difference, followed by 300 -400 strokes on 80 grit and than 200 on 100 grit and 200 on two grit. At this point surface finish wasn’t a big concern. The concern was the condition of the edge. After 200 grit chipping was along entire edge. I removed chips using 120 grit silicon carbide stone, which took me about 30 passes plus deburing. After that I decided to use only 80 grit and up. Removing chips created significant flat on the edge. But it took only 100 strokes on 80 grit to create a apex. I switched to 100 and than 200. Chipping still was bad. About 20-30 more cuts into 120 silicon carbide and edge is straight. I followed the same routine: apex with 80, than 100 and 200. Still chips on the edge, couple of them really big. The blade of my pakistani knife looks much more narrow than just two day ago 🙁 .Whole test took about two hours. No big deal: I was watching Criminal Minds.
Probably tomorrow I will stone edge again and will work only with 100 and up. Should be fine, but you never know. At this point I have no desire to use 50/80.

[Mikedoh]

I wouldn’t apex with the 50 or 80. Only use them to thin the bevel behind the apex so the higher grit stones have less work to do. I only use VERY LIGHT pressure with the 50/80.

[Roman]

Probably you are correct and I am trying to use these stone not as it was intended

[tcmeyer]

I try to keep my coarse stones (=<200) away from the apex entirely, as it takes too much work with the 400's to remove the scratches that the coarse stones can produce.

My theory is that a deep scratch being produced by any grit can cause break-outs (chips) at the edge which are effectively much deeper than the scratch itself – hence the need for the extra effort.

[Author]

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