Archive for August, 2010

Customer Review: Chosera 2K, 5K, 10K Edge Pro Stones + DMT Extra Coarse for the EP

August 24, 2010

This is a comprehensive review of the Chosera 2k, 5K, and 10K Stones for the Edge Pro that a customer posted on The Knife Forums. It touches on many of the major arguments both for and against using the Edge Pro stock stones, and the Choseras for the Edge Pro.

The full thread with all of the replies can be seen here.


When reading this review please bear in mind that I am new to the EP. I have had many years experience sharpening woodworking tools, chisels, plane blades etc, and have sharpened all my own kitchen knives for a long time using wet & dry paper together with 3M Mylar film on glass backing.

There are those on this site with centuries more experience than I, and there are those who have sharpened several thousand for every one knife I have done.

That said I will report as logically, honestly and knowledgeably as I possibly can. Bear in mind the views expressed are mine and are worth, as a friend of mine is want to say, exactly what you paid for them.

The test was conducted as objectively as possible given my set up, resources and experience. The results are however highly subjective and personal.

I believe I possess a reasonably logical mindset and I lean toward the sceptical. I accept little until proven and am highly value driven – bang per buck is king and knives to me are tools.

Ireland is a country with very stringent gun and knife laws. Knives are found in the kitchen, are owed by fishermen, divers, sailors, climbers and other specialist endeavour / interest groups. Trades people all have knives in their tool kits, typically utility knifes of the disposable type such as those manufactured by Stanley – the market leader. The very very large majority of knives in Ireland are traditional Western style (French / German) kitchen knives.

Test Run 1

To compare the Chosera 2,000, 5,000 and 10,000 with 2,000, 3,000 and 7,000 EP tapes

The Knives:

Two identical Wusthoff Classic Chefs Knives. Bought the same day from same wholesaler – these knives had been sharpened by me previously so were in reasonable shape. Knives are for home use only and are well looked after receiving only a regular touch up on a ceramic hone between sharpening. The knives are sharpened at 17° on each side, 34° included. Normally knives would be sharpened as far as 600 grit stone.
One knife was marked A the other B.

The Process:

I sharpened each of the knives alternately on the same stone one knife after another in the same progression starting with 320, and progressing through 600 and 1,000 stones.

A marker was used at each stone change on each knife to ensure that the exact same angle was being hit with each stone progression.
Standard EP techniques were used to de-burr together with hard felt to remove all traces of a burr before progressing to the next stone.

Paper slicing testing together with the three finger test at this stage showed zero differences between the two knives.

Knife A was then further refined on new standard EP tapes in the progression 2,000, 3,000 and 7,000. Both the 2K and the 3K were mounted on standard EP aluminium blanks the 7,000 was mounted on a glass blank.

Knife B was further refined on the new Chosera 2,000, 5,000 and 10,000 stones.

Visual Inspection

Knife A – the tape treated knives showed atypical levels of finish and polish, with superior levels of polish and high performance paper slicing results. Standard A4 80GSM photocopier paper, newsprint and 3M post it notes could all be slice and push cut.

Knife B – the Chosera finished knife showed a slightly higher level of polish with less scratch marks being evident. Standard A4 80GSM photocopier paper, newsprint and 3M post it notes could all be slice cut and push cut but with an ease not evident with the tape finished knives.
The three finger test on the tape finished knife was similar to tests I had conducted before on similar knives taken to this level.

The three finger test on the Chosera finished knife provided feedback not experienced before. This knife felt considerably sharper and had to be treated with considerable respect during the three finger test.

Magnification test

I currently use a cheapie 30X Loupe to check my edges. The Chosera knife and Tape knife showed a relatively high level of uniformity along both horizontal and vertical axes of the bevel with the Chosera knife displaying a slightly better uniformity of scratch pattern. Scratch pattern depth on the Chosera knife was also more regular with the Tape knife displaying the odd slightly deeper scratch.

The edge difference between the two knifes was however quite evident. A toothiness seen in the tape knife was not present in the Chosera knife and the edge on the Chosera knife was noticeably more regular or straight.

Overall Impressions

If asked to select the better finished knife I would opt for the Chosera knife – it is hands down the winner in terms of polish, finish and sharpness.

If 100 average people at a shopping mall were asked to compare the two knives I doubt if more than 1 or 2% would notice the difference.

A pack of 2,000 polish tapes costs $7.00 for 15 tapes – a 2,000 grit Chosera stone costs $36.00.

A pack of 3,000 polish tapes costs $7.00 for 15 tapes – a 5,000 grit Chosera stone costs $36.00.

A pack of 7,000 polish tapes costs $7.00 for 15 tapes – a 10,000 grit Chosera stone costs $60.00.

The Chosera stones were on special sale at the time I bought them so the price I paid was less than that detailed above. See the Jende Ind. web site for current pricing.

I would normally get between 4 and 5 knives out of each polish tape. Based on the costs above I would need to get 385 knives out of the 2 and 5K Choseras for them to work out at the same cost per knife and I would need to get 640 out of the 10K stone for the two options to work out at the same cost. This of course assumes that equal results are obtained from both the tapes and the Chosera stones. My initial impressions are that the stones provide a superior finish but we are talking at an extreme level compared to what most (99%) of users are used to.

The Chosera stones are considerably thicker than the standard EP stones – I would be reasonably confident that achieving the above number of sharpening per stone would be achievable.
There is the debate about having to change tapes every 4 to 5 knives versus the more continuous use of the stones. Stones however do need flattening – to what degree with these stones I have yet to discover but more of this anon.
If asked whether tapes or high level stones are necessary to get very sharp knives – I would say no.

If asked if one wanted to experience a well finish polished bevel at very low cost – I would advise that you try the tapes.

If asked that if money was no object which system would I prefer – I would undoubtedly opt for the Chosera stone approach.

In my view the Polish Tapes are very accurately named – they do yield a very nice polish when used after a 600 or 1,000 grit stone and where the scratch marks of the previous stone have been eradicated through each stage. They do not, in my humble estimation, have a huge effect on the edge in terms of contributing additional sharpness i.e. edge angle reduction, they simply don’t appear to have the cutting power after the first couple of passes to achieve this objective.

By contrast the stones are not a surface only abrasive medium – new layers of abrasive material is constantly being exposed thus giving the stones the edge in the cutting performance stakes. Allied to this is a level of polish equal, if not superior, to that of the tapes.

Test Run 2

Sharpening Japanese Knives on Chosera Stones

I have used Japanese chisels for many years. I bought one to begin with and then bought many more afterwards. I personally have never used or sharpened a western chisel that compares with a Japanese.

I am however very, very new to Japanese knives. I bought two Japanese knives six months ago – a Hiromoto Aogami Super TJ-50AS 120mm Petty from Koki and a 210mm Tojiro DP Gyuto from Mark.

Neither had yet been sharpened and had received nothing but an odd touch up on a ceramic hone.
Today I sharpened the Hiromoto Aogami at 12° each side and the Tojiro at 15° each side. When purchasing the Choseras from Tom & Ken I also took the opportunity to get a mounted DMT XC. The DMT took all the work out of grinding the new bevels.

I then took the two knives through all the EP grits up to 1,000 before progressing to the Chosera 2K, 5K and finally 10K.

When I had finished I used both knives to prepare dinner this evening – mainly prep work on onions, carrots, potatoes, courgettes and the like.

Although both knives were sharp out of the box I believe I can now say that I have never held a sharper knife in my hand. I realise that both these knives are low end and budget compared to knives used by the majority of knife nuts reading this but for my purposes they are quite simply superb and more than adequate for the tasks my culinary skills can ask of them.

Test Run 3

To fill out my knife collection I wanted to add a slicer. I did not however wish to part with the $$ necessary to acquire a Japanese version mainly because it would get only occasional use.

To bridge the gap, and due in no small part to the acquisition of the EP, I snagged myself a 4 Star Elephant marked Sabatier slicer. Using my 120 – 1,000 EP stones and tapes I set about putting a very low angle bevel of 10° followed by a 15° micro bevel on one side having previously completely flattened the back side.

Today I re-worked the knife using my EP stones and Chosera stones. The edge I had put on the knife simply didn’t stand up to any sort of prolonged use. So I re worked the bevel again at 10° but put a micro bevel of 15° on both sides.
I’m hoping that the knife will perform almost as well in terms of slicing abilities but will hold its edge considerably better given that the included angle is now twice what it was previously.

I have not, as of yet had the opportunity to put the knife through it’s paces however in terms of finish it is as good if not slightly better than previously.

Choseras – Ramblings & afterthoughts

As previously mentioned the Choseras are thicker than the standard EP offerings. However I could not get the ramp high enough to meet the edge of the Chosera stones which in effect meant that I could not risk using the entire length of the stone for fear of catching on the edge. This leads me to believe that the middle of the stone will dish sooner than if one could use the full length.
Tom, Ken or anyone else reading this – if you have a solution or workaround I’d be happy to hear it.

The 5K stone feels very different to me. It is a thirsty stone and is almost reminiscent of an old Arkansas very fine oil stone I used to use many years ago.

Ken, when he was mounting the 10K stone left it wide and bevelled the edges. This proved useful in terms of productivity and will, I’m sure, extend the life of the stone. With its extra width it made fast work of the polishing process.

The feedback from the stones is infinitely better than that of the tapes. From day 1 I have found it difficult to feel or read what the tapes were doing.

The Choseras on the relatively soft Wusthoff knives created quite a bit of mud. This I cleaned off at very regular intervals. When using the same stones on the Japanese knives they created a lot less.

Having used the Choseras for the test runs outlined above would I buy them again – the plain and simple truth is I really don’t know yet, time will tell. If they hold up as well as I expect them to and I get reasonably equivalent life out of the stones compared to the tapes then I would say yes. But if I were to discover that I had to buy a new set of stones after say a couple of hundred knives – maybe not.

Although not strictly relevant to the report here – I really really hate the standard EP 220 stone. The 120 is no great shakes but the 220 is just awful. I normally try to avoid using the 220 but for the Japanese knives I reckoned that the jump from 120 to 320 would be asking a bit much of the 320. On reflection I should have just persevered with the 320 rather than suffer that horrible 220.

That’s about it for my initial feedback. Hope somebody gets some use out of the ramblings.


Shapton Professional vs Glass Stone Scratch Mark Comparison

August 1, 2010

Here are some direct comparison pictures of the scratch marks left by Shapton Professional and Glass stones, as documented individually here and here.

The same grits make it easier to compare, but for those without the same grits have been grouped to show their relative positions and results, as demonstrated by the 4K, 5K and 6K stones. I also compared the 15K Pro and the 16K Glass.

Full size pictures are here, here, and here.