ERU sharpener review. Latest Feedback 2/14

Fred.Rowe

Fred.Rowe

Joined
May 2, 2004
Messages
6,848
What do you say to a handheld adjustable tungsten carbide knife sharpener that can be set to sharpen every thing from a straight razor to an ax?
It is adjustable from 16 degrees inclusive to 40 degrees inclusive or any degree setting in between. The carbide faces are 95 HRC.
I spent a month going around measuring sharpening angles on pull through carbide and ceramic "V" sharpeners. Not a singe one had an inclusive sharpening angle less than 29 degrees with most being in the 30 to 35 range. These angles are fine for cleaning up the edge on an ax, but not so much for a 20 degree, kitchen slicer or 24 degree hunter edge.
So after a little hair pulling, pencil sharpening, coffee drinking a few thousand dollars, this is my solution.


To me its the perfect solution, filling the need for an adjustable field sharpener that will adjust to any sharpening angle and can be carried in the palm of your hand.


Coming up with a sharpener that could be adjusted to sharpen scandi ground blades was a priority. At 24 degrees inclusive it will sharpen bevels 15/16 inches high.
It can be clamped in a vise or held securely in its sheath/protective holder.


This is not a sales thread; we will be machining in Jan. 2014 and they will be available then; I'll post here on BF when we get them run.


ERU stands for "edge renewal utility".





Fred











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The sharpener is made to be used, held in its holder, to protect your fingers.


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Trying to get a better example of an edge done with the ERU. This blade is a forged 1084 that I made and carry every day. Its only seen the ERU for a year and a half. If done with good technique this carbide "V" sharpener will keep a great working edge on most all your knives. This is a 24 degree edge with a 28 degree micro bevel. The micro can be seen in the middle of the bottom pic.
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Won't that still tear the edge up like the other pull-through carbide sharpeners? I don't think I'll be ordering one.
 
wvdavidr said:
Won't that still tear the edge up like the other pull-through carbide sharpeners? I don't think I'll be ordering one.
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No not really. The reason most carbide draw through sharpeners tear the edge or actually dull the edge is the degree setting thats used. If you try to sharpen a 20 degree inclusive edge in a 35 degree "V" sharpener it will tear the edge up. Using an adjustable carbide strip sharpener set at 20 degrees; sharpening that same knife will result in a sharp edge and one that has not been abused. Its the setting and not the carbide that does the damage. If you consider this a moment I think you will agree. You may have to get one to prove it to your self. :)
 
No I don't think so. Ive seen the damage a carbide sharpener can do....

I would probably be behind this product if it was a ceramic similar to the spyderco UF as opposed to carbide.
 
Sadden said:
No I don't think so. Ive seen the damage a carbide sharpener can do....

I would probably be behind this product if it was a ceramic similar to the spyderco UF as opposed to carbide.
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I must disagree; I've sharpened hundreds of blades, with the carbides set at the proper angle and have never seen the the edge damaged. I've had four proto types in the hands of hunters and trappers for the last year, where they were asked for any critical input and damaging the edge was never a concern. When you put a 24 degree edge in a 35 degree carbide sharpener you will damage the edge. I tested dozens of the set market sharpeners and all of them were 30 to 35 degrees and they all damaged the edge. The proof of course is in the testing and not in hearsay. I don't like ceramic because it clogs so easily. Thanks for posting, Fred
 
Hunters and trappers are the last people I trust to judge an edge.

With that aside I think we are all looking forward to some micrographs showing a comparison between this and any decent waterstone.
 
I bet it would work well to thin the edge too before using something like a sharpmaker.
 
Sadden said:
Hunters and trappers are the last people I trust to judge an edge.

With that aside I think we are all looking forward to some micrographs showing a comparison between this and any decent waterstone.
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Excellent idea. Thats a broad brush you use there in painting millions of hunters and trappers as poor judges of what a sharp edge is. I'm a knife maker by trade and have ground thousands of edges; I will agree not all people know what sharp is. With water stones or any plate sharpener its the skill of the sharpener in maintaining the correct angle that dictates the end results. Its a guess at best. I make and use a Bubble Jig to set and sharpen all edges in the shop. The edge angles set in this manner are exact; I strip the wire edges using the ERU set at the same edge angle. It takes one pass. Its a very useful field sharpener.
If I am looking for an opinion on how a car drives; I would probably ask a race car driver and not a car salesman wouldn't you think?
 
Kronos said:
I bet it would work well to thin the edge too before using something like a sharpmaker.
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Since the angles are exact its easy to maintain an edge once it is set. I know every knife edge angle of every knife I have by sight. Its a very different experience when sharpening with a true angle set.
With a little magic marker on the edge you can see in a hurry how true the edge is. I've tried sharpening blades that appeared to the eye to be straight but when passed through the ERU you can see they are not even close. There are blades out there that can not be sharpened.
 
Sadden said:
Hunters and trappers are the last people I trust to judge an edge.

With that aside I think we are all looking forward to some micrographs showing a comparison between this and any decent waterstone.
Click to expand...

No offense to any hunters here but I have agree with that statement and I would add, many hunters don't know how to hold a angle consistantly & properly. The proof is in many of the hunting knives that come through my shop for sharpening that look like they thought they were sharpening a straight edge razor and then maybe a knife at the same time.
Scratch marks from a stone all the way up to any secondary bevel and then the spine too!

This is exciting Fred,
The proto type looks very handsome and well thought out without being over done.
I hope this works out well for you and I am looking forward to hearing some more reviews.
 
Rhinoknives1 said:
No offense to any hunters here but I have agree with that statement and I would add, many hunters don't know how to hold a angle consistantly & properly. The proof is in many of the hunting knives that come through my shop for sharpening that look like they thought they were sharpening a straight edge razor and then maybe a knife at the same time.
Scratch marks from a stone all the way up to any secondary bevel and then the spine too!

This is exciting Fred,
The proto type looks very handsome and well thought out without being over done.
I hope this works out well for you and I am looking forward to hearing some more reviews.
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Lawrence,

Thank you for the encouragement Sir!

I don't think its specifically hunters that don't know sharp; its just that there are so many of them. I know you do a lot of sharpening and no doubt cringe at some edges you encounter. Same goes for trappers.
Most in both of these groups don't "study" edges the way knife makers and people who sharpen for a living do. Truth be told there are not a great many people who understand how to develop or maintain a good edge.


Thanks for posting, Fred
 
Cool idea. Might be a good pass around item. Put a couple into circulation on here and see what our members think. Could be some pretty cheap advertising! Just a thought... Russ
 
mycough said:
Cool idea. Might be a good pass around item. Put a couple into circulation on here and see what our members think. Could be some pretty cheap advertising! Just a thought... Russ
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That's a good idea.

I think the general feeling here is that there are consumer demand products (those that work somewhat well, and are very easy and quick to use) and then there are the products that cater to those that seek the best quality edge that they can achieve, time (and often times cost) be damned.

There seem to be few products that bridge the gap well.

I, for one, would be willing to test your device, should you decide that type of thing is a benefit to your product.
 
Fred - look like you've put a lot of thought into this product, an adjustable sharpening 'v' angle is brilliant.

1. Do the tungsten carbide faces rotate or allow shifting? I am asking because over time the WC faces will be worn down by VC, which will affect the knife apex and somewhat the bevel. Sure, it won't be a problem for knives without or a little VC.

2. From your estimate, how much abrading vs burnishing go into the pull/pinch sharpening stroke? Say a D2 at 60rc for example.

3. About what finishing grit range the result be? again D2 example with feather light pull stoke.

4. Lastly, what to do for a convex edge?

Sorry about asking too many questions but while back I was thinking about using a WC scrapper as a sharpening tool, luckily you get there first with something much better than my envision :D

Thanks
 
Do you have a ballpark guess for pricing yet? I certainly wouldn't ever touch a straight razor with something like this, but I can see it being useful for setting an accurate bevel in a pinch. It's definitely an attractive package.
 
bpeezer said:
Do you have a ballpark guess for pricing yet? I certainly wouldn't ever touch a straight razor with something like this, but I can see it being useful for setting an accurate bevel in a pinch. It's definitely an attractive package.
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If you look in sales we have a thread posted.

Fred
 
Fred.Rowe said:
Lawrence,

Thank you for the encouragement Sir!

I don't think its specifically hunters that don't know sharp; its just that there are so many of them. I know you do a lot of sharpening and no doubt cringe at some edges you encounter. Same goes for trappers.
Most in both of these groups don't "study" edges the way knife makers and people who sharpen for a living do. Truth be told there are not a great many people who understand how to develop or maintain a good edge.


Thanks for posting, Fred
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This is pretty much true, but in reality the edges these people get work for them. I have a friend who sharpens on nothing but a pieceof sandstone, but will butcher a cow in the back of his flatbed for a meat-processing company his grandpa left to him. Truth is the kind of edges that these scrapers leave generally will work pretty well for meat, since they're so coarse...

Fred,

I really like the idea, I thought the thread in sales was a little bit more enlightening on the carbide inserts. Specifically...

What you will find with this tool is the fact that the carbides "exactly" match the cutting edge the abrasives don't chew up the leading edge but instead buff the actual edge bevels as it was originally ground.
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I thought this was imporant, I actually have a carbide pull-through with adjustable inserts, but the facet which the edge bevel makes contact against was angled as such that it left the sharp, coarsely ground edge of the carbide bit to cut into the steel. It was actually very much like a cutting bit on a lathe, wouldn't be surprised if they had just bought a bunch of those to use. But yeah having the facets of the carbide teeth flush with the edge bevel, at a good 90 degree offset to the rest of the device is what really makes this intriguing to me beyond the angle measure.

I'm interested in how fine the bits are finished as bluntcut pointed out.

Also in the other thread you mentioned you might be thinking about diamonds or ceramics--that would be a really great move.

What I think you recognize and understand is that what people need is a tool that offers quick functional convenience, but also observes good sharpening principles. As bluntcut said, it's abrading and not burnishing--not acting like a big carbid cutting bit, but as you pointed out actually buffing/polishing flush to the bevel surface. Ceramics and diamonds would be a really good little addition, but the carbide is a good choice with this implementation I think--it's hard enough that it will set that edge back well. I don't think I'd advocate using this for straight razors though even with finer abrasive inserts, the design itself just lends too much susecpitbility to having an accidental "shearing" incident that could be catastrophic for a razor--I'd also be worried about chipping on a really hard kitchen knife.

To people poo-poo'ing this, I would recomend you look at this in comparison to using a fine non-grooved steel, but taking a huge amount of the angle control out of the equation.
 
My grandfather's words of wisdom: "Don't knock it until you have tried it." If it works as advertised, you may have a winner there. Most people other than the "extreme knife knuts" on here (myself included) want a quick down and dirty sharpener that will get their knives back up and cutting what they need to cut with little effort or expense expended. I sharpen a lot of kitchen knives that have usually been abused with a cheap pull through sharpener or an expensive "Chef's special" electric knife destroyer by the owners. They were almost to a person satisfied with the results from their efforts. After having their knives "really sharpened correctly" (in my opinion at least) they were astonished with the results and the resulting ease of use with their knives. Something like this if successful would put a lot of people like me :D out of business. Which in my case is not to bad as I am retired and only sharpen knives as a hobby and as a very limited income. (enough to buy a cup of Starbucks every so often) I hope you are successful and look forward to the final product.

Blessings,

Omar
 
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