Hollow grinding a U2 - need maker

[Dan Gray]

YOU GUYS ARE GIVING ME A HEADACHE!!

***********

 

[thombrogan]

Thanks, Dan. I thought it was funny, but maybe a bit too pointed, so I edited it all out. The previous post was directed towards Dr. Agocs, not Cliff or Tom.

 

[Chiro75]

Oh, come on, that's not fair! I didn't get to see the original! If I get dissed I should at least get to see what was written!

 

[Dan Gray]

Thanks, Dan. I thought it was funny, but maybe a bit too pointed, so I edited it all out. The previous post was directed towards Dr. Agocs, not Cliff or Tom.

Steve
I quoted it look back a few posts..

thom
I'll take it off if you want but we are playing with pointed things after all

 

[Cliff Stamp]

My restriction is just against it being forged.

That's too bad, after the blade was reforged I was going to have Wilson reharden the plastic handle including deep cryo and have Busse make up a set of INFI pins.

I want to see you ...

I have been internet active for more than 10 years, always under my own name, and always making it known where I live. Drop by. I have about 15 truck loads of wood to clean up this summer, I could use a hand.

so do you have a dremel

Yes.

In the past it seemed he tried to destroy blades, but here he was looking to increase cutting performance at the cost of strength.

I still do the former, people want to see it. The reviews don't simply represent what I want in a knife, a lot of it is done on requent.

However cutting ability optomization has always been a large part of the reviews, the first customs I had made had thin blades on full hard steels. The reviews also contain a lot of regrinding to favor cutting ability at the sake of durability such as this :

http://www.physics.mun.ca/~sstamp/images/pacific_salt_modified.jpg

A Pacific Salt reground to a thinner edge, it would have been better to hollow this out, but I can't do that so I flat ground it instead. I left the edge at the formed angle (~6 degrees) but it collapsed on 3/8" hemp, it works fine with secondary edge bevels from the Sharpmaker, just a few microns thick.

In fact there is far more of this type of information in the reviews than gross damage, the breaks are just more sensational. You post a ten page review talking about various aspects and in the end you pry with the blade and it snaps and many people just see the break. That's cool, it takes all kinds.

I just got asked to work with a heavy bowie including some very extreme work that could very likely damage the blade. The guy wants to see it done compared to some other knives I have. Should I not do this because some people here are not interested in it. That seems like an odd perspective to have.

My hat is off to the guy grinding on a stone!!

It is the five gallon bucket that is the secret, without that it all goes to pieces. Lots of really nice looking pieces on really basic equipment like the neo-tribal guys. The setup that the HI forgers use makes Alvin's look like rocket science.

-Cliff

 

[Dan Gray]

That's too bad, after the blade was reforged I was going to have Wilson reharden the plastic handle including deep cryo and have Busse make up a set of INFI pins.
-Cliff

why would you have to reharden the plastic handle??
once plastic has been hardened by cryo
you shouldn't have to do it again?

 

[Chiro75]

Thanks for the heads-up, Dan! Thom, sometimes I am a little thick (thicker than my knives, at least!) so I don't know whether your comments were an insult or a compliment! I'll assume compliment because that's just the way I am. FWIW, I have never actually peeled an orange with the Tactical Orange Peeler. The name came about because the first one had blaze orange G-10 scales and I wanted a funny, cutesy name, so Tactical Orange Peeler seemed appropos. I will make a longer handled version, too, someday, called the Tactical Grapefruit Peeler because we all know that you need the extra leverage when dealing with those vicious bastards!

 

[Dan Gray]

Tactical Grapefruit Peeler because we all know that you need the extra leverage when dealing with those vicious bastards!

I see a few of them creeping around here once in a while
dang yella varmints especially the ones ..........with! seeds

 

[Chiro75]

They can shoot venom straight into your eyeball from several yards away, so watch 'em if you spot one in the wild!

 

[Cliff Stamp]

why would you have to reharden the plastic handle??

That was a joke, Thom has had Wilson reharden some S30V blades to raise the hardness and thus improve edge retention.

-Cliff

 

[Dan Gray]

That was a joke, Thom has had Wilson reharden some S30V blades to raise the hardness and thus improve edge retention.

-Cliff

Stihl has their plastic handle bars Nitrogen enhanced to make them stronger
you must not have known this could be done..
that's not a joke..

 

[thombrogan]

Dr. Agocs,

The first part was poking a little fun at your offer to test Cliff's knives with a slight reminder of recent testing offers you've made. Hey, if you can't let a guy post a thread without you making references to chopping concrete, you can take a little ribbing, right?

The second part was regarding the desire of your customers to have 1/4" thick steel in a knife that benefits from wafer-thinness and a hyperbolic explanation for that desire.

Dan Gray,

You can keep that quote there. You caught me going too over-the-top and apparently wanted to give me a good reminder of why I should reread my Carnegie book more often. Glad you didn't dig through my trash ten years ago and send my purposefully incorrect tax return to the authorities to show them that even though I was forthright in reporting my income, I had the capacity to claim a $10,000 deduction for sending blank VHS cassettes to the US Consulate in Ougoudougou, Burkina Faso.

Is the nitrogen enhancement part of the plastic's composition or were the bars frozen in nitrogen?

Cliff Stamp,

No need for INFI pins, I'd be happy with 4142. And happy with a Phil Wilson heat-treatment, too. WTF is up with the RC62 butter-soft steel? I want a blade - not pillow batting!

 

[Cliff Stamp]

Stihl has their plastic handle bars Nitrogen enhanced to make them stronger

The U2 is going to be hollow ground on already thin stock, handle strength isn't an issue, the blade would break long before the existing handle would fail, that was the basis for the joke, the "need" for INFI pins hinges on the same complex.

It also references overbuilt designs in general, knives which are really strong in some respects, but trivial to damage in others because the designs are incoherent. That is something Thom mentioned recently on another thread, and something I have been discussing in another recent thread.

It was also referencing the suggestion of forging the profile, which would add extreme complexity to the process if it could even be done, with no functional gain assuming the end geometry is the same. It was simply continuing that line of thought.

-Cliff

 

[Dan Gray]

Stihl has their plastic handle bars Nitrogen enhanced to make them stronger

The U2 is going to be hollow ground on already thin stock, handle strength isn't an issue, the blade would break long before the existing handle would fail, that was the basis for the joke, the "need" for INFI pins hinges on the same complex.

It also references overbuilt designs in general, knives which are really strong in some respects, but trivial to damage in others because the designs are incoherent. That is something Thom mentioned recently on another thread, and something I have been discussing in another recent thread.

It was also referencing the suggestion of forging the profile, which would add extreme complexity to the process if it could even be done, with no functional gain assuming the end geometry is the same. It was simply continuing that line of thought.

-Cliff

cliff it's hard to tell when you joke or just don't know something?
is that by design?
Nitrogen enhancement is used on many things not just carbon steels
Harley uses it on cycle engine blocks. it's done on Cast Iron auto blocks for racing. Plastic's
use your or or something if your joking ok so we know maybe

I do want to see a hollow grind put on an already flat ground thin blade.
it won't be enough to make a difference I'm sure other than a place to brake.
try it
the best way is to start with an ungrounded blade, first put the hollow in
where you want it, you'll have your grinding grove to follow, then flat grind it.
even in 1/4 stock at 1 1/2" wide steel with the flat at say 1 1/4" you'll have very little hollow left. try it
it's a very interesting out come.
I tried that with my new model re-con XL1 I just made , I started it over and just hollow ground it.
I mentioned to Roger L what I was trying to do, some time ago before this thread..

I see why you don't care about what the grind lines look like, you can't keep them right like that,,
if you have any hollow left at all...the buffer will wash it out,

 

[Tom Krein]

Cliff,
E-mail sent.

Tom

 

[Cliff Stamp]

[hollow a flat ground blade]

try it

I have, used them, not made them, that is why I wanted to get this one done. It makes a large difference if the grind is deep enough in terms of cutting ability and many times to one in terms of ease of sharpening because of the reduction in material contact.

-Cliff

 

[Dan Gray]

as I said be for

I do want to see a hollow grind put on an already flat ground thin blade.
it won't be enough to make a difference I'm sure other than a place to brake.
try it
the best way is to start with an ungrounded blade, first put the hollow in
where you want it, you'll have your grinding grove to follow, then flat grind it.
even in 1/4 stock at 1 1/2" wide steel with the flat at say 1 1/4" you'll have very little hollow left. try it
it's a very interesting out come.

I tried this with my new model re-con XL1 I just made , I started it over and just hollow ground it.
I mentioned to Roger L what I was trying to do, some time ago before this thread..

I see why you don't care about what the grind lines look like, you can't keep them right like that,,(by hand)
if you have any hollow left at all...the buffer will wash it out,

 

[Cliff Stamp]

As I noted Dan, I have it done and it makes a difference.

Take a flat ground blade 1/8" thick, and a half an inch wide. At 1/4" from the edge it is +1/16" thick, or +0.0625, that is the thinnest and assumes you grind to zero and then sharpen back, otherwise it is thicker still.

There is no limit to how thin it can be if you hollow grind it, you can go right to the limits of flexibilty of the steel, so 0.010-0.015.

Obviously it will cut differently at 1/4 the thickness. Now as you thin the blade stock you flat grind, the difference decreases, but even on really thin stock, 1/16", you are looking at more than double the thickness for an optimal flat.

Alvin has been doing exactly this (hollow grinding flat blades) for twenty years, with all of his knives being users, and thus feedback isn't a problem. It you are not seeing a difference you are simply not grinding a deep enough hollow.

-Cliff

 

[Dan Gray]

As I noted Dan, I have it done and it makes a difference.

Take a flat ground blade 1/8" thick, and a half an inch wide. At 1/4" from the edge it is +1/16" thick, or +0.0625, that is the thinnest and assumes you grind to zero and then sharpen back, otherwise it is thicker still.

There is no limit to how thin it can be if you hollow grind it, you can go right to the limits of flexibilty of the steel, so 0.010-0.015.

Obviously it will cut differently at 1/4 the thickness. Now as you thin the blade stock you flat grind, the difference decreases, but even on really thin stock, 1/16", you are looking at more than double the thickness for an optimal flat.

Alvin has been doing exactly this (hollow grinding flat blades) for twenty years, with all of his knives being users, and thus feedback isn't a problem. It you are not seeing a difference you are simply not grinding a deep enough hollow.

-Cliff

Cliff it won't be a true hollow grind properly done, it can't be. or it's another animal your calling hallow grind...you have only but one place for the deepest part of the hollow to be so you are limited .I want to see it done..

now if you want to do a running back razor edge grind then that's a different story
but it's not a true hollow as most know it.. .and a flat grind on it would have no propose on it.

 

[Cliff Stamp]

By hollow I simply mean the primary grind is concave, not a specific orientation of the curvature. A small Sebenza has a fairly deep hollow grind, it should be easy for you to handle one of them. Now compare that to the same blade with a flat grind, there is a lot material removed in contrast and now realize that the Sebenza is still way thicker than optimal for a pure cutting knife, you could cut it about in half and thus make the difference even larger.

-Cliff