Who uses 50 and 80 Ultra/Extra Coarse Stones?

[Geocyclist]

My 100# diamond stones are now broken in. I sharpened a Cutco knife tonight, taking it down to 17 degree per side. It was probably 20+ to start with. Seemed like it took for ever to raise a bur for the initial re-profiling. I looked up Cutco steel and it looks like they use 440A which is low carbon and super high Chromium (16-18%). No doubt this is part of the problem.

I am wondering how everyone re-profiles, 100# or who has the 50/80s? What are your thoughts? I am thinking there is a trade off of speed in re-profiling vs. having some deep scratches to work out later (or can’t get out)?

I am still working through my “junk” to average knives before I start my “super steel” knives. I want to perfect my technique and learn from my mistakes on my lower end knives. I assume that better steels will sharpen/re-profile faster. Maybe I just need more patience or do you like the ultra coarse stones? Or do they cut too deep?

If you use the ultra coarse do you use them on all re-profile jobs, or just on the harder steels?

[Martin L]

I love my 50/80s. They cut the time down to reprofile the harder steels like crazy.
I have yet to try them on the “super” steels but I did try it on my kabar mule which was taking me forever to reprofile with the 100 and it literally went from possibly hours to minutes!!
I raised a burr in no time.
I think they are essential in the kit to be honest. As for taking out the deep scratches, I don’t think it’s that tough.
I’ve put mirror polishes on each one I’ve done even after the 50/80.
I would definitely give them a try if I were you.

[Marion]

go ahead and use the 50/80 grits. Take your time and give extra strokes as you increase your grits. If you have been working heel to tip, then change and run tip to heel. Just like in sanding wood and polishing plastics, and glass you have to break down the abrasion scratches into smaller and smaller bits.

Even some of the not so super steels take a good while to reprofile. A certain Becker#2 in 1095CrV comes to mind… Still it has a near mirror finish.

440 series stainless steels used to be concidered supersteels 30 yrs ago.

[Lukas Pop]

I now well broken 100/200 and quite new 50/80 now. I did many reprofiles with 100, so now are finer than my 200, so I use progression 200>100>400>600…. My 50/80 works much faster than 100/200. Stratches are quite deep, so I have to spend lot of time with my 200 ( I recommend to use small hand microscope from dealextreme to control taking out deep scratches), but in sum, it can spare a lot of time when heavy reprofiling. I think the scratches will become much shallower as my 50/80 will break in.

I have some knives made from similar steels to 440A, and reprofiling of them is quite fast in comparison with some other steels.

[Ted S]

LukasPop,
How many knives did it take to wear down your 100 grit to be finer than your 200? Thought I read somewhere that the diamonds would be to sharpen around 500 knives.

[Lukas Pop]

LukasPop,
How many knives did it take to wear down your 100 grit to be finer than your 200? Thought I read somewhere that the diamonds would be to sharpen around 500 knives.

Hi TedS, I did about 25 reprofiles. If you don’t need to reprofile, the amount of work is much less. The edges after 100 grit look very well under microscope now, but the speed of reprofiling is reduced. I don’t know how long this state will persist. But it seems to me that diamonds are rounded only, not removed from the base, so I think they have much time ahead. I suppose finer grits to endure very long as you don’t use (you shouldn’t) pressure when refining the edge.

[Martin L]

( I recommend to use small hand microscope from dealextreme to control taking out deep scratches)

I was wondering which microscope you were talking about on the website. I was looking and they have a bunch.

[Xbander]

I am wondering how everyone re-profiles, 100# or who has the 50/80s? What are your thoughts? I am thinking there is a trade off of speed in re-profiling vs. having some deep scratches to work out later (or can’t get out)?

If you use the ultra coarse do you use them on all re-profile jobs, or just on the harder steels?

Thoughts on the 50/80s; have re-profiled the edge on 12 Chicago Cutlery kitchen knives. My 50/80 are not even close to breaking in. Several of the 12 did get some deep scratches that may never come out. That is Ok since I am just after a good cutting edge on them. Keeping a light touch works better and they are quick to set up a nice starting profile. When you first start the 50/80 they are hard to describe how rough they are. I would want them to break in a lot more before I would consider using them on a more expensive knife.

[Lukas Pop]

( I recommend to use small hand microscope from dealextreme to control taking out deep scratches)

I was wondering which microscope you were talking about on the website. I was looking and they have a bunch.[/quote]
This one http://dx.com/p/60x-100x-zoom-microscope-with-led-illumination-light-25239

[Ken Schwartz]

I haven’t used the 50 and 80 grit diamond plates, so I couldn’t comment on them directly.

I do make the Atoma diamond plates for the Wicked Edge in 140 400 600 and 1200 grit.

The Cutco steel isn’t a particularly hard steel – just the opposite. And you aren’t drastically changing the angle or reprofiling the knife to an extreme angle (which I wouldn’t recommend doing on a Cutco in any case).

The 140 Atoma will make short work reprofiling a Cutco – or any of the much more highly abrasion resistant steels as well.

It is one of the most popular products I make (also for the EdgePro) specifically for this purpose of creating an initial reprofiled angle. I usually recommend following this with a finer diamond plate for more abrasion resistant steels or going to a stone like a 150 Nubatama waterstone or 220 grit Shapton Pro stone. The stones ‘convert’ from a diamond scratch pattern to a ‘softer’ waterstone pattern.

—
Ken

[Geocyclist]

Ken,

Thanks for the info. I guess my technique wasn’t that good early on. The Cutco’s were my first knives to sharpen on the WE, and also the ones that took the breaking in of the diamond stones.

For everyone else what I have learned is use the 50/80 sparingly/cautiously. I find I don’t need them more than I think. Now that my diamonds stones are broken it the 100 feels smooth, almost like the 200, but it still cuts fast enough for pocket knives. The 50/80s are broken in now too. I feel now they don’t remove as much material as when virgin, but still leave deep scratches. Last time i used them I spent a lot of time on the 100 and 200’s to get the deep scratches out. My opinion now is for small to medium pocket size knives with thin blades 100’s will get the job done and save the work of getting deep scratches out of a fine blade. For me they still have a place with re-profiling very large, and very thick blades.

[Ken Schwartz]

Yes it is worth emphasizing that all diamond lapping plates go through a break in period. Initially, the finish is coarser and more irregular and more aggressive. After breaking, it is more consistent but looses that initial aggression. Why waste it? Use that initial breaking for flattening some coarse stones or roughing in a big bevel. Be aware of some loose diamond stones from a plate causing errant scratches or getting mixed into the mud on a stone.

—
Ken

[blacksheep25]

As has been pointed out, the 50/80 stones will leave deep scratches, and IMHO, I wouldn’t try and raise a burr with those coarse stones either. I’m trying to figure out a good way of explaining what I’m thinking… okay, say you have a 3 layer cake which represents you knife to sharpen, and your end goal is to re-profile (or just sharpen) such that when you are done (e.g. 50/80->100/200…1200/1600->strops), you would end up removing all three layers. So do you take the 50/80 and grind through all three layers? Or do you perhaps use the 50/80 to cut through say most of the top layer. Then you use the 100/200 to cut part way through the middle layer, then the 400/600 for the rest of the middle layer; then 800/1000 and you’re starting to cut into the bottom layer. To further clarify, say the 50/80s cut scratches that are 1-1/2 layers deep, if you go all out and burn through most of the 3 layer cake, you’re going to be there a long time remove scratches, which is what people have been saying.

So my approach would be to not try to get 100% of the re-profile done with the coarse stones; instead I’ll try to get 80% there with the 50/80, then switch to the 100/200 to get to 90%, then the 400/600 to get to 93%, then 800/1000 to get to 95%… until you get to your final edge/finish at 100%.

Using the above method, I’m not hitting the last 1/32″ of the edge until I get to the 400/600 stones. Sometimes I under estimate, and have to go back to a coarser grit, but the more I practice, the better (easier) it is to figure out when it’s time to go to a finer stone. I’ve also found that making cross hatch scratches makes it easier to monitor the progress of the re-profile.

[cbwx34]

As has been pointed out, the 50/80 stones will leave deep scratches, and IMHO, I wouldn’t try and raise a burr with those coarse stones either. I’m trying to figure out a good way of explaining what I’m thinking… okay, say you have a 3 layer cake which represents you knife to sharpen, and your end goal is to re-profile (or just sharpen) such that when you are done (e.g. 50/80->100/200…1200/1600->strops), you would end up removing all three layers. So do you take the 50/80 and grind through all three layers? Or do you perhaps use the 50/80 to cut through say most of the top layer. Then you use the 100/200 to cut part way through the middle layer, then the 400/600 for the rest of the middle layer; then 800/1000 and you’re starting to cut into the bottom layer. To further clarify, say the 50/80s cut scratches that are 1-1/2 layers deep, if you go all out and burn through most of the 3 layer cake, you’re going to be there a long time remove scratches, which is what people have been saying.

So my approach would be to not try to get 100% of the re-profile done with the coarse stones; instead I’ll try to get 80% there with the 50/80, then switch to the 100/200 to get to 90%, then the 400/600 to get to 93%, then 800/1000 to get to 95%… until you get to your final edge/finish at 100%.

Using the above method, I’m not hitting the last 1/32″ of the edge until I get to the 400/600 stones. Sometimes I under estimate, and have to go back to a coarser grit, but the more I practice, the better (easier) it is to figure out when it’s time to go to a finer stone. I’ve also found that making cross hatch scratches makes it easier to monitor the progress of the re-profile.

Sounds like a good plan of attack (and explanation), and you’re right, you definitely want to try and avoid reaching the edge with the 50/80g stones.

[Matthieu Methot]

Great info once again. This forum has made it so much more enjoyable to get through the learning curve. I just wanted to ask some of the people that have the 50/80 stones if they found any irregularity’s in the thickness of the stone on the platens one of my 50s is a full 16th out of the platen then the other end of the same stone. I think i saw some one else had a video on you tube with the same problem or is it a problem when starting with such a cores stone? should I call we?

[Author]

Posts