"Blowing out the spine" on chef's knives?

L

Leon Husock

Joined
Jul 17, 2019
Messages
320
I made a chef knife a while ago and a friend/mentor of mine said I'd "blown out the spine", i.e. the plunge grind at the transition (the little ricasso-like square between the heel of the chef's knife and the tang, I'm not sure what the actual term for it is) went all the way up to the spine so the transition became sort of like a very thin integral bolster. He pointed this out as a mistake, but he also largely does bowies where I can see it being more of an issue aesthetically. The nice thing about this sort of grind on a chef's knife is it allows the tang to be thicker, say around 3/16", while the actual spine of the knife stays very thin.

My question is, is this something I should work to avoid, or is it more of an issue on the type of knife where the plunge grind is more prominent?
 
Agree it is kind of an aesthetic thing, though not really typical. Does look cool. I think the biggest thing might be the risk of fracture at that point due to stress risers if the plunge is not well rounded. Probably not a huge issue as a chefs knife really should not be used with a lot of lateral torque ... but something to keep in mind.

Cool looking blade!
 
What C Cushing H. said, it does create a stress riser there that wouldn't exist if you blended the tang. but if you mistreat it enough for that to break you've probably already destroyed the edge. it's definitely distinctive
 
Leon Husock said:
Does a link to an instagram post work? I don't have an account on any of the sites that work to post images here from. https://www.instagram.com/p/CJ4b3mPDejD/
Click to expand...
That's a great looking knife. I am not normally a fan of a step in the spine and would prefer a hidden plunge, or the way Don Nguyen does a lot of his, with the plunge line on the neck of the knife and a smooth transition into the spine.

You can post on imgur without an account. I'm not on Instagram and their site often wants you to sign in to see posts, but your pictures showed up for me without issue.
 
Thanks everyone! I'm glad you all liked it. Maybe I'll make some more with the little step down like that.
 
I’ve heard it referred as breaking the spine.
Typical it’s frowned upon and considered a mistake. In your case it looks intentional and it looks very good in the profile view. I’d like to see a spine shot.
 
3fifty7 said:
I’ve heard it referred as breaking the spine.
Typical it’s frowned upon and considered a mistake. In your case it looks intentional and it looks very good in the profile view. I’d like to see a spine shot.
Click to expand...
Honestly that might've been the term he used, this was a while ago now. Unfortunately I don't have the knife anymore and I didn't take a spine shot when I had it since it was already spoken for by the time I finished it so I didn't take as many pictures as I usually would to post something for sale.
 
Honestly the abrupt tradition between blade and the ricasso looks pretty bad. It's a hard line on on otherwise flowing design. Just the hint of a soft transition would look awesome.
But that's just personal opinion, and who am I but just another amateur talking nonsense!
 
A.McPherson said:
Honestly the abrupt tradition between blade and the ricasso looks pretty bad. It's a hard line on on otherwise flowing design. Just the hint of a soft transition would look awesome.
But that's just personal opinion, and who am I but just another amateur talking nonsense!
Click to expand...
It's so hard to tell! Maybe I can keep the thicker ricasso but smooth the transition a bit. Like I said before, the main reason I want to do this is a practical one, i.e. it's a pain in the ass to make a handle to fit a tang that's .09" thick which is often how thin the spines of my chef's knives end up.
 
Do you think you can gain the control to sweep the plunge a little? Just enough to smooth the sharp transition from Ricassovto spine? That would still be a cool look, but not quite so abrupt…
 
A.McPherson said:
Honestly the abrupt tradition between blade and the ricasso looks pretty bad. It's a hard line on on otherwise flowing design. Just the hint of a soft transition would look awesome.
But that's just personal opinion, and who am I but just another amateur talking nonsense!
Click to expand...
I’m with you. I don’t think plunges belong on a kitchen knife.
 
looks intentional to me, and you have a rationale for it that explains your intention. Doesn't look like you blew it.
 
only thing to add that if the sharp edge is where the fingers go in pinch grip chefs will hate you. dont know how your doing your fittings but small endmills woudl great as long as you dont push them too hard i have a bunch of 3/32 just for kitchen knife fittings. my steel starts life .113 tho not .090
 
Leon Husock said:
It's so hard to tell! Maybe I can keep the thicker ricasso but smooth the transition a bit. Like I said before, the main reason I want to do this is a practical one, i.e. it's a pain in the ass to make a handle to fit a tang that's .09" thick which is often how thin the spines of my chef's knives end up.
Click to expand...
you can make a 3 piece frame handle and pin the whole assembly together
you can make a short cap that is easier/shorter to fit and then the longer handle piece behind the cap you can drill a larger hole.

like this and this
 
Leon Husock said:
It's so hard to tell! Maybe I can keep the thicker ricasso but smooth the transition a bit. Like I said before, the main reason I want to do this is a practical one, i.e. it's a pain in the ass to make a handle to fit a tang that's .09" thick which is often how thin the spines of my chef's knives end up.
Click to expand...
All kitchen knife I make are from 1.5mm thick steel
jEbSMmm.jpg

XkSU5rd.jpg

juEPlPd.jpg

XazB7rr.jpg

YCH1GDu.jpg
 
You must log in or register to reply here.
Back
Top