Kurokubi

Question about bevels

Recommended Posts

No idea whether or not this is the proper place to put this but I was wanting an more in depth explanation as to whether or not the transition between the edge bevel and the secondary bevel will effect a blades cutting ability. I'm not talking about a ridiculous 20° edge and a 40° secondary.

I'm talking about a much closer transition but one that's not quite as smooth as it could be.

I suppose the better phrasing would be "is it possible for the secondary bevel to create drag or hinder the cut in any way"

Share this post


Link to post
Share on other sites

Yes.  
 

For my own blades I prefer to use the slack belt area of my grinder to make a slightly convex edge grind... thus I don’t really have a secondary bevel... but do enjoy the effects of one.  This has the added advantage of creating a very smooth, slick cutting, transition that is easily repeated and good looking.  If I do, in some clumsy way, end up with a rough looking transition... I will round it over a wee bit to make it look better and work better too!  Mostly we are talking very subtle refinements here, of course, nothing that average users could detect... except for the appearance.

Share this post


Link to post
Share on other sites

Ridiculous 20, secondary 40....I am not certain what do you like to say/ask....:blink:

Mostly I grind blades down to a thickness of 0,20-0,30 mm so that they flex on my bare thumbnail.

A blade that is ground so thin and sharpened with a  primary bevel of 20 Degree , is not ridiculous at all.

Well, that cuts like poison!

Those 0,20-30mm can be easily stropped down to zero....rolled edge is the term, I guess.

That is the old school and best edge You can get on a knife blade.

Based on that, the "meat" behind the edge determines how strong Your edge will be....

So the secondary40 means the blade flanks?......please enlighten me

Cheers

 

 

Share this post


Link to post
Share on other sites

yes is the answer . the smoother the transition the easier the blade will pass through material.

 

Share this post


Link to post
Share on other sites

I hope that the OP comes back to respond - I too, am curious about the geometry he is describing.

Smoothness of transition certainly reduces the forces neccessary to travel through the cut........

If the thickness behind the cutting edge encourages spreading or separation of the cut material, the spreading and shearing forces work together to accelerate the cutting action.

Robert Taylor

Share this post


Link to post
Share on other sites

Also depends on the type of cutting the blade is designed to do---which is why razors, knives and axes all have a differing geometry. (And a skinning knife and a "camp knife" will even have differing geometries.)

Share this post


Link to post
Share on other sites

There's a pretty comprehensive PDF regarding sharpening and edge angles. If you look through the topics in this section you'll find it. 

Pnut

Share this post


Link to post
Share on other sites
11 hours ago, Steve Sells said:

Forty degrees is a bit steep, much closer to an Axe than a knife

Thats what I thought.

19 hours ago, basher said:

yes is the answer . 

 

Quote

 

so the answer is definitely not" Yes" ....that aint a smooth transition...pretty coarse wedge

Share this post


Link to post
Share on other sites

yes is to the question:-

 

"is it possible for the secondary bevel to create drag or hinder the cut in any way"

definite yes!

Share this post


Link to post
Share on other sites
On 11/17/2019 at 2:45 PM, Kurokubi said:

"is it possible for the secondary bevel to create drag or hinder the cut in any way"

Yes, 100% the steeper the angle the more effort required and friction to overcome to push it through something. 

Pnut

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.