My first big HT disaster !

MarkJeffrey

MarkJeffrey

Joined
Nov 7, 2013
Messages
262
Lets celebrate!!! :applouse:

Well, I cracked a blade before.. but this.. this is new. I've spent way too many hours on this razor, only in the end while hand sanding to realize something wasn't right. Here's the weird thing (to me).. up to about the last little while of hand sanding the cutting edge bounced right back when I tried it as it got thinner and thinner, then I noticed my sand paper starting to bur the edge a bit.. then I did this with my FINGERNAIL. Hard to tell in the picture but the steel actually splits super easy, not just bends. What on earth did I do wrong.. I was really surprised, angry, and found it somewhat comical all at the same time. 1084 (the easy HT steel?) heated to 1500 in an evenheat kiln, 130* canola oil quench, 2 temper cycles at 400 for 1.5 hours each. At least that's what I think I did.. I dont drink.. so I'm pretty sure I didn't do anything out f the ordinary haha

I have another razor I did at the same time only rough ground so far. I'll obviously be redoing the HT on that thing.

I'd really like to come out on top and at least learn something from this experience, so any input would be much appreciated









 
A couple of my Wharncliffe knife blades have done that when I got the thickness of the edge less than .008". At .007" the edge can be flexed with my fingernail. At .004" the edge breaks.

Have you tried setting the edge back just far enough for the edge to be about .008" thick or thereabouts?
 
That's what I was going to saw, at that thickness even hard steel won't take much to deform.
 
I agree that the edge is probably too thin. Without some skill and really good equipment, you really don't know if the edge is .005 or .002" thick.

Other suspect is that the blade/edge is too hard.
 
Thanks for the comments. If I take the edge back that far it will mess up the geometry needed for honing a razor, this is 1/4 in thick at the spine and already at 13/16 to the edge. I could try but I might just hang this one up on the wall of shame.

Stacy, if the edge was too hard would those pieces not break off rather than tear and bend? Not trying to question your knowledge Ive learned a lot reading your posts I'm just trying to wrap my head around what I've done wrong here.

Also, on the topic of edge thickness, what is considered a zero grind if .005 is too thin?

Thanks again!
 
With a zero grind it is just that no thickness left on the edge, a good exzample of this is a scandi grind. It only has a primary edge bevels and thy are at a set angle. When sharpening you sharpen the entire flat. But most zero thickness have there primary grind brought down till the blade is sharp then a very small hair secondary grind. But this also means the material behind this zero grind is thick enough to support the fine edge. I don't know much about razors so I can't help you there but Stacy will point you in the right direction.
 
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Honestly, razors aren't my thing either. You might want to ask this question on the razor forum. I can move it there for you.
 
Stacy E. Apelt - Bladesmith said:
Honestly, razors aren't my thing either. You might want to ask this question on the razor forum. I can move it there for you.
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You can, I was just hoping more for input on the heat treat problem itself. I dont know if this would be considered strictly a razor problem or not.. maybe because of the thickness of the blade I suppose. I'm literally just sitting here at the computer with it every time I pop on the forum, still poking my finger nail into the edge making more and more marks. But yes, I'll try over there and see if I get any bites if you want to move the thread, thanks

Matt R said:
Same here! Only problem is that my smallest wheel is an 8".
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JTknives said:
I run an 8" and 2" wheel but am considering adding more.
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I used an 8" wheel to rough grind this one, then went in with a 5" wheel to hollow it out more after "HT" :rolleyes: . You could use an 8" wheel on a 7/8 or 8/8 razor though, I think it ends up being called a quarter hollow grind.
 
Yea 1/4 spine and you can go around the 7/8 razor give or take, it depends how high you take the grind and how much shoulder you leave to give you an exact angle when you hone it, but everything I've been looking at was basically in around this. I'm still learning the geometry. The first razors I made were small fixed blades, with not nearly enough thickness to the spine for the blade's height,. I didnt even know that was a factor when I started on these.
 
One of the members on a razor forum posted this in reply to a question I asked on thickness, it's .004 at the edge and .010 1/4 in from that.

 
Man now I got the itch to try my hand at them. I have been fighting the urge to contact butch and picking his brain.
Do you know of any tutorials on making one? I have been reading about them and so I know just enough to get me In trouble.
 
So do you guys figure steel at that thickness will deform from pressure of a fingernail at say 59hrc? Not trying to beat a dead horse here I'm just confused. That's in around where my HT should have gotten me, or is my blade too hard, too soft, or wha. I cant chip the edge it just bends then tears.
 
JTknives said:
Man now I got the itch to try my hand at them. I have been fighting the urge to contact butch and picking his brain.
Do you know of any tutorials on making one? I have been reading about them and so I know just enough to get me In trouble.
Click to expand...

Check i to the straight razor place forums. Good info for geometry and such for sure.
 
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