question for zero grinders

Is this a trick question? I think it depends on the thickness of the stock and the width of the grind. The angle could be from 1 degree to 89 degrees. Please give us some details.
 
Take the thickness at the spine and the blade width at the center of the blade.Use those and your high school geometry and you will get the blade angle.To make the edge last for more than two cuts,give it a micro bevel secondary at about 5 degrees more than the edge.
Stacy

OK here is the site:
http://www.projects.ex.ac.uk/trol/scol/calrtri.htm
use the spine thickness as "a", blade width as "b", and you will get blade angle "A"
This is close enough for calculating blade angles. To do it exact use 1/2 spine thickness as "a" and width as "b" and double the "A" answer to get the exact angle.( too much work for a few 1/10th of a degree difference.

For an 1/8" thick blade,1" wide the angle is about 7 degrees.
 
I have a blade design that i have made, but I am trying to determine what thickness bar stock to use, I know what I want the grinds to look like in profile when I'm done but I dont know what kind of angle I want on it, for example 1/4" bar stock would be a 17.76 degree angle, while 3/16" and 1/8" would be 13.37 and 8.93 degrees respectively. Sorry about the confusion...my fault. Thanks.
 
The mechanical engineer in me says, "Hmm... let's think..."

The bladesmith in me says, "You're over-engineering it... Just grind it!!!" :p :D

I've made over a hundred blades with zero grinds. Steel selection and heat-treat are going to be big factors in how steep of an angle you can get away with.

I don't agree with Stacy on this one though, I've not found a secondary bevel necessary. It kind of defeats the purpose. If you're going to be doing a lot of heavy cutting, I'd recommend you fore-go the zero grind and go for a flat grind that gets very thin with a slight convexity to it. But that's just my $0.02 :cool: :)
 
Nick, I agree with you.
I usually just grind and polish them into an apple seed edge.
On the micro bevel,I was referring an edge that was a true flat grind zero edge.For a razor type instrument (microtome blade) it is OK.For a cutting tool or kitchen knife (especially a Japanese edge) I add a very small secondary ( same applies to chisels and engraving tools), to prevent chipping.I often just hone it in on the leather belt.(That is what I was doing when I lost part of my hand last year) Some of my sushi knives only have a 3-4 degree edge.I hone them flat to 8000 grit on water stones.Without that little secondary at about 8-9 degrees,it doesn't take much to dull it down.On those edges, long cycle Cryo and a final Rc of 60-62 are needed.I'm in the process of testing CPM154 at these extreme angles.
As a side note,If you buff your blade edge to remove the wire,you are adding a rounded secondary.Even stropping does it a bit.Look at one at high magnification.
 
Nick, maybe that's a good thing...seeing as how I want to be a mechanical enginetter that is :D I think I'm going to go with 1/4" stock, mainly because I'm kinda rough on knives and that way I know I wont mess it up if I do any chopping with it.
 
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