It is currently Tue Aug 04, 2015 7:28 am

All times are UTC



Welcome
Welcome to chefknivestogo

You are currently viewing our boards as a guest, which gives you limited access to view most discussions and access our other features. By joining our free community, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content, and access many other special features. In addition, registered members also see less advertisements. Registration is fast, simple, and absolutely free, so please, join our community today!





 Page 1 of 1 [ 8 posts ] 
Author Message
 Post subject: Accuracy of EP angle markers?
PostPosted: Sat Jun 27, 2015 6:35 pm 

Joined: Sun Mar 08, 2015 3:56 pm
Posts: 15
Just used my EP Essentials Kit (shapton stones) for the first time last night on some Shuns, but I had a little trouble with the angle markers (colored dots) on the EP. My Shuns have only been sharpened by the factory, so they should be 16*. I started just above the red mark, to approximate 16*. Both the sharpie trick and the level on my iphone said I was too acute - iphone read 12*-ish. After some trial and error, I wound up right at the green dot for 18*, yet the iphone was reading 15*. Am I doing something wrong?

A few factors I'm considering are that I don't know how accurate the iphone level is, and the natural bevel on the Shun is very thin and therefore hard to read with the sharpie trick. The shapton stones are also thin, so that could be it too. I spent a good amount of time on the knife, so I'm a little worried that I've put on too obtuse of an angle and can't go back down to the 15*/16* I wanted to be at after removing so much metal.

Also, how big of a factor is the amount the knife hangs over the edge of the machine? It varies throughout the process a bit (due to the shape of the knife and my lack of skill).


Offline
 Profile  
 
 Post subject: Re: Accuracy of EP angle markers?
PostPosted: Sat Jun 27, 2015 11:40 pm 
User avatar

Joined: Wed Aug 28, 2013 10:09 pm
Posts: 211
You want to keep the knife parallel to the blade table with minimal over-hang. You can encounter angle variance depending on how much of an up-sweep there is at the tip. Here's the explanation for the angle difference you are experiencing: http://www.chefknivestogoforum.com/post99171.html#p99171


Offline
 Profile  
 
 Post subject: Re: Accuracy of EP angle markers?
PostPosted: Sat Jun 27, 2015 11:43 pm 

Joined: Tue Jul 15, 2014 4:52 am
Posts: 197
Location: Auckland, New Zealand
Hi Mike,

You can pretty much forget about the coloured markers on the EP because they simply can't factor in things like stone thickness, overhang etc.

Keep persevering with the Sharpie method as it tells what's really going on. If you're not using any magnification then I would say its worth getting a 20X or 30X Loupe, so that you can see where your stones are grinding in relation to the actual bevel.

Knife overhang is another cause of the angle changing & you can take a couple of different approaches here.
1) You can just accept that the angle changes a bit down the length of the blade by a degree or two and as long as you set up & sharpen the knife in the same way each time, you should still get sharp edges and acceptable repeatability.
2) You can modify your setup & your techniques to reduce the variability. It depends on how OCD you are!

I did some approximate measurements on one of my Euro chef's knives that has a lot of belly, and using the standard setup recommended by EdgePro Inc the overhang varied by about 15mm which translated to approx 1.25º. Good rule of thumb a half inch difference in overhang changes the angle by approx 1º.

Regarding measuring the angle, I have been using my iPhone for the last couple of years or more, and recently an angle cube.

With the iPhone I use an app called "Clinometer" (the pro version I think), which I find brilliant. Its consistent and repeatable. You can zero the iPhone on the blade table and then put it onto the back of a mounted stone and read the grinding angle directly. The OCD bit is that I mark the midway point on the sides each of my stones with a Sharpie and then set the stone up in the EP with the midway mark resting on the front edge of the blade table. Then I put the iPhone lengthways onto the blade table between the blade guide and the edge of the table so that it sits flat. (Make sure you don't use the edge with the volume buttons on it!). Then zero the angle and sit the iPhone square & flat onto the back of the mounted stone centering it with the sharpie mark on the stone. Let it settle and the read off the grind angle. Repeat for a check if you want.

Very similar procedure with the angle cube. I haven't yet perfected the technique with the angle cube, but that's just operator error & practice. The reason I am trying to go to the cube is that its less expensive if it drops onto the concrete floor of my garage!!!

Hope this helps



_________________
Cheers Grant

Just because you're not paranoid doesn't mean they're not going to get you!!
Offline
 Profile  
 
 Post subject: Re: Accuracy of EP angle markers?
PostPosted: Sun Jun 28, 2015 2:29 am 

Joined: Sun Dec 30, 2012 11:01 pm
Posts: 673
Location: ATL
I'm going to suggest you check the fit where your horizontal rod meets your vertical rod. The tops of the two plastic blocks should be roughly parallel. If you somehow get them backwards (which I've done) you'll be off by 2º or so and they will not be lined up. In the end trust your iphone app assuming you've zero'd it.


Offline
 Profile  
 
 Post subject: Re: Accuracy of EP angle markers?
PostPosted: Sun Jun 28, 2015 12:18 pm 
Forum Moderator
User avatar

Joined: Mon Apr 23, 2012 4:45 am
Posts: 1867
Location: Skype k_schwartz
The marks are very approximate. Radar has pretty much wrapped up the topic thoroughly. +1

---
Ken



_________________
ksskss@earthlink.net
My Facebook Page
Ken Schwartz Forum on CKTG
Ken'sCorner
Offline
 Profile  
 
 Post subject: Re: Accuracy of EP angle markers?
PostPosted: Sun Jun 28, 2015 1:53 pm 

Joined: Sun Mar 08, 2015 3:56 pm
Posts: 15
good advice everyone, very much appreciated....the knife (especially considering it was my first try) came out pretty well, so I'm sure with some refinement I'll get some awesome edges. Thanks!


Offline
 Profile  
 
 Post subject: Re: Accuracy of EP angle markers?
PostPosted: Sun Jun 28, 2015 1:59 pm 

Joined: Sun Mar 08, 2015 3:56 pm
Posts: 15
also, is it possible that i choose to obtuse of an angle and re-profiled my knife from 16* to something higher? Could that be done with a shapton 500 in one session? and if so, how easily can i get it back down to a more acute angle? just hoping i didnt do something permanent


Offline
 Profile  
 
 Post subject: Re: Accuracy of EP angle markers?
PostPosted: Sun Jun 28, 2015 8:43 pm 
User avatar

Joined: Thu Jul 10, 2014 12:50 am
Posts: 340
The only thing you can do permanently while sharpening manually is remove steel. No matter how good your glue is, the steel just won't go back on.

If you reset the bevel too obtuse, you can make it more acute by just lowering the angle on the pivot block, but it will take a bit longer because you have to abrade the shoulders of the previous bevel down. A Shapton 500 can definitely do either, but not as fast as something in the 120-250 grit range.

When using stones, those marks on the pivot post are unreliable. It's best to set the angle for each one. The stop collar is a shortcut, and does pretty well at allowing you to only need to adjust for your first stone. When you get tired of setting angles for each stone, then you can get some diamond films and matched blanks and really go to town without worrying about readjusting angles frequently.



_________________
-Chris

Got Bacon?
Offline
 Profile  
 
Display posts from previous:  Sort by  
 Page 1 of 1 [ 8 posts ] 

All times are UTC


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  


suspicion-preferred