I receive my Shapton Stones last week, but just this evening attempted to sharpen a knife with them. I did not notice until I was working with the 15k/30k stones that the stones were not a consistent thickness. This makes it impossible to maintain a consistent angle. The attached photos tell the story.

I will contact the WEPS office tomorrow. Help!!

RalphHoneycutt wrote:


I can see what you mean about the thicknesses. I've reached out to Ken at Precise Sharpening and Tom at Jende Industries, both our resident Shapton experts to explore how common/critical this is. I've asked them to weigh in here on the forum. I'll also be available all day tomorrow when you call.

RalphHoneycutt wrote:


Ralf - What a sweet set of Shaptons!!

Thank you for bringing this up - you took very good pictures to illustrate the differences.

There is a lot of cleanup that goes into making the stones flat after the cut which translates into varying thickness. And because of the more limited dimensions of the Shaptons (compared to the Choseras), Ken tries to keep any and all loss on the stones to a minimum when cleaning them up. The difference is more noticeable when cutting 2 stones for the WEPS.

Just to cover all bases, this variation in thickness was mentioned with the earliest introduction posts on my blog, on question #3 (here)



The varying thicknesses can be easily overcome with using the Angle Cube and minutely adjusting the arms of the rods on each side to match the desired angle with each stone. If you're OCD enough (like me), you'll find that there is enough variation on every WEPS paddle to warrant the adjustments between grits.

Personally, as long as the stones come at least 5mm thick, I feel the differences in thickness are manageable with the angle cube. But if it is going to be a widespread concern, it is something I'm sure Ken can add to the QC process.

I'm not sure if Ken will chime in - I don't think he's even registered here - but I will bring this up with him.

Tom, Thanks for your reply. I will call and talk to WEPS (Clay, if he is available). The difference in thickness of the stones and the width of the stones make using them with the increased angle adjustments a bit more tedious than I expected. The width of the stones is also approximately 1/8" to 3/16" narrower than the diamond stones and the Chosera Stones. This is approximately 17-25% less stone contact with the edge. Combining these 2 issues (decereased width and inconsistent stone thickness) could be cause for additional safety concerns when using these stones. USers should be made aware of this IMO.

Please understand, I am not complaining. Being an engineer, I look for solutions. I am one of Clay and WEPS's most loyal disciples.

I appreciate all of the expertise demonstrated by yourself, Clay, and many others on the forum.

Thanks again your reply.

Hi Ralph,

Clay asked Tom and I to respond. I think Tom did an excellent job responding, but I would like to add a few more comments too. And very much appreciate the opportunity to discuss this topic.

These Shapton stones are cut by hand as opposed to automated processes and I try my best to maintain precision in the cutting process, but inevitably error accumulation does creep in as any cabinetmaker or woodworker knows. You will usually find me walking around with a micrometer sticking out of my pocket.

First let me address the width issue of the stones. The whole Shapton stones are usually 17 mm thick, slightly less than the 3/4" width of the blanks. On occasion, from cutting another shape from a stone, I can go to doing a cut in the opposite plane and getting a wider piece available, fully filling the 3/4" blank. Rather than risk taking off the difference of 2mm (3/4 inch is 19 mm), I prefer to give the customer more stone than he paid for rather than less. So sometimes the stones will be wider. To me I prefer to err on the side of giving more stone.

Regarding stone thickness, there will be variations in the thickness. Sometimes a good bit. This does vary from day to day for a number of reasons beyond the scope of this discussion. If the variances are a lot (relatively speaking), I have to compensate for this by cutting the stones thicker, which significantly (negatively) affects my yield rates. And spending considerably more time getting the stone to within specification. Cutting a stone too thin yields a total loss, so I tend to 'give' extra.

As Tom mentioned earlier, the spec is for a 5-6 mm thick stone. As you can see in the pictures, the stones in the pictures significantly exceed that thickness. Even more significant height errors can occur from the blade angle being off by one degree. I am constantly calibrating these angles but ultimately need to fine adjust for this degree of skew by hand, lapping the stones individually.

This skew issue is one commonly seen by freehand sharpeners and EP users as well. Fortunately, in each of these instances, especially in the design of the Wicked Edge sharpener, the stone pivots freely and compensates for this small height variation. If not, even with flattening, enough stone should remain to meet the specification. Personally I would prefer a slight degree of skew and getting a lot more stone. The stone surface should be FLAT, but a slight degree of skew should not matter.

Regarding actual stone thickness, as Tom mentioned, as stones wear, the thickness variation should be taken into account and an angle cube is the tool for the job. You could lap all your stones to the same height constantly (NOT recommended), but since your 30k stone will wear VERY slowly compared to say a 320 grit stone, you really don't want to just flatten and wash your 30k stone down the drain.

Flattening stones and adjusting skew is an inherent part of the sharpening process. As your stone wears down you will be making adjustments to keep your stones flat and control skew over the life of each stone.

I hope this is a reasonable explanation showing a bit of what goes into handcrafting these Shaptons for the WEPS machine and maintaining them over their lifespan.

---
Ken

Ralph,

If you would like for me to flatten these stones more precisely, please send them to me and I'll be glad to do it.

Regards,
Ken

Ken & Tom, Thanks for your replys. Your comments and insights are much appreciated. I had a pleasant conversation with Clay this morning and have decided to return the Shapton Stones. As indicated to Clay, I am very happy with everything received from WEPS to date with the exception of the Shapton Stones. Call me cheap, but for approximately $1,100, I expected consistent flat/square stones that are of the same level of quality of everything else that is provided by WEPS. Call me lazy, but I do not want to have to use the angle cube in between each pair of stones.

I indicated to Clay that when the QC improves on the Shaptons or I can be assured of flat/square stones, then I would gladly purchase them again.

I hope my comments have not been too harsh. I initially failed to fully appreciate the hand craftsmanship that goes into cutting these stones for the WE system.

Thanks again.

No worries, Ralf!

I appreciate your honesty, and respect your decisions based on your reasoning.


Ken - thanks for jumping in with a better explanation than I could ever give!

Hi Ralph,

I will ask Clay to return the stones you have purchased to me and get a new set to you that are PERFECTLY square as measured with a calipers to within a hundredth of an inch. I will, if you wish, photograph them so that you can be completely reassured that they will meet your expectations.

I would hate to see anyone deprived of using these excellent Shapton stones on your Wicked Edge
Just let me know if this is a satisfactory arrangement. I take customer satisfaction very seriously.

I do appreciate your comments and take them not as harsh but rather as constructive criticism. If there is a problem that someone brings to my attention, as you have, I can (and will) fix it. If someone 'goes away' and doesn't let me know why, I can't fix it. So simply, THANK YOU.

---
Ken

RalphHoneycutt wrote:

Ralf,

Ken and I are already discussing this with Clay, and we'll come up with a plan to take over the world, for sure!

One thing I'd like to comment on about the WEPS forum is that the stand-up attitude of everyone here really makes it a great tool for discussion. Despite there being some sensitive issues, no one is ganging up or trying to cause a riot. Just good, gentlemanly discussions that all add the the betterment of the WEPS.

*edit* looks like Ken already spilled the beans on the evil plan!!!