Author Topic: Tip Torture Test  (Read 3853 times)

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Offline Red

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Tip Torture Test
« on: January 26, 2015, 10:02:30 PM »
Yeah, it broke.. but that was kinda the point :P (no pun intended :D )
Make sure you switch the thingy to HD :thumbsup: And sorry, my body cam mic sucks... adjust volume as needed.


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Offline PetrifiedWood

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Re: Tip Torture Test
« Reply #1 on: January 27, 2015, 12:09:45 AM »
Cool video! It definitely took a beating. You mentioned 1095 needing a faster quench than O1. I concur. When I was making the strikers the first numbered batch were oil quenched O1. The next batch were 1095 and I tried oil quenching and they weren't getting hard enough to spark. I started quenching in warm water (much faster than oil) and that made them hard enough to throw massive sparks.

I used the straight across grind method you described and it does result in a gradual increase in edge angle towards the tip. But I did it more for the sake of convenience than by purposeful design. I have drilled every hearth board so far just like in the video though! :D

As for the tip snapping, I would bet that probably 85% or more of every knife you can buy in a store would snap its tip under those conditions. You run into physics and there is a limit to what even tool steel can withstand. Tip geometry plays a part, but most knives are not built with someone trying to snap the tip on purpose in mind. Most experienced knife users could use that knife for a lifetime without subjecting it to those conditions. I'd have no reservations against carrying it as my only knife.


Offline trentu

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Re: Tip Torture Test
« Reply #2 on: January 27, 2015, 04:08:08 AM »
Very well done test! I'm with PW on the percentage of knife tips withstanding that test. As long as it survives drilling then that's a good tip. I have had good screwdrivers bust opening a can of paint so it is pretty much using the right tool for the right job. I think you got the heat treat spot on as demonstrated with the side impact stress test.
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Offline MnSportsman

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Re: Tip Torture Test
« Reply #3 on: January 27, 2015, 04:24:32 AM »
  Pretty cool video, Red! I was chuckling with you & the "sword in the stone" comment.
:D


  As was said... Most folks wouldn't be that harsh on their knives, but it was cool to see that you were checking on your quality control & some of what ya do to make sure your getting out a quality knife.
:thumbsup:


  Thanks for sharing!
:)
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Offline Yeoman

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Re: Tip Torture Test
« Reply #4 on: January 27, 2015, 06:49:46 AM »
Cool vid.
I thought using water for a quench didn't work because of the formation of a steam barrier.


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Offline Highlife

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Re: Tip Torture Test
« Reply #5 on: January 27, 2015, 06:55:24 AM »
Nice vid for more than just the tip test. Good confidence in the knife and heat treat.
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Offline OutdoorEnvy

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Re: Tip Torture Test
« Reply #6 on: January 27, 2015, 08:00:59 AM »
Cool vid Steve!  I liked it!

Question for the knife experts (that means you makers).  For tip strength would scandi or convex be stronger?  Just curious if you all have played around with it or not. 
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Offline trentu

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Re: Tip Torture Test
« Reply #7 on: January 27, 2015, 09:02:55 AM »
Cool vid Steve!  I liked it!

Question for the knife experts (that means you makers).  For tip strength would scandi or convex be stronger?  Just curious if you all have played around with it or not.
In my experience a convex is usually a little tougher tip because it leaves more thickness but how thin the geometry of the tip and if the tip was over heated when it was ground has a lot to do with it.
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Offline PetrifiedWood

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Re: Tip Torture Test
« Reply #8 on: January 27, 2015, 10:24:32 AM »
Cool vid.
I thought using water for a quench didn't work because of the formation of a steam barrier.


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This from wikipedia:

Quote
Water is one of the most efficient quenching media where maximum hardness is acquired, but there is a small chance that it may cause distortion and tiny cracking. When hardness can be sacrificed, whale oil, cottonseed oil and mineral oils are used. These often tend to oxidize and form a sludge, which consequently lowers the efficiency. The quenching velocity (cooling rate) of oil is much less than water. Intermediate rates between water and oil can be obtained with water containing 10-30% UCON from DOW,[clarification needed] a substance with an inverse solubility which therefore deposits on the object to slow the rate of cooling.

There are as many opinions on quenching as there are metallurgists, and wiki can be hit or miss. But my limited experience bears out what is said here. A water quench is rapid and violent, and can cause stress fractures and warping of the steel. But it does cool the steel extremely fast and make it very hard.

Offline Yeoman

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Re: Tip Torture Test
« Reply #9 on: January 27, 2015, 01:51:35 PM »
Thanks PW. Good to be reminded not to get hidebound in our ideas. I'll have to do some more digging before I do my next project.


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Offline Red

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Re: Tip Torture Test
« Reply #10 on: January 27, 2015, 04:27:49 PM »
It performed just as I suspected it would, given the way I grind. Drilling holes was fine, but slamming and bending the tip like that, there just isn't enough metal at the very tip to withstand abuse like that. I could either change the way I grind (not going to happen) or keep it the way it is and have a nice fine edge at the point for intricate carving.

So, anyone who wants one of my knives, be warned: If you repeatedly slam my knife tip into something and fold it down, the tip will break, and a new tip will need to be ground on it.

The whole thing behind this test was a few years ago I gave Trent a knife, and he was drilling a hole in some wood and the whole tip broke off. Not the tippy tip like here, but a good 1" of it. My HT has come a long way from those days, and I wanted to see how it stacked up this time around.

I would be impressed if someone could show me a knife ground like mine, from the same steel that could do that test and survive. GO!
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Offline upthecreek

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Re: Tip Torture Test
« Reply #11 on: January 27, 2015, 04:49:07 PM »
That's pretty good beating you gave that blade. I'm glad I didn't recognize it :) I liked the wacking it with the big stick after driving it in the log. Impressive. Seems to me you have your recipe down. Is that you new grind profile? A kit might be a fun project for me.

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Offline Red

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Re: Tip Torture Test
« Reply #12 on: January 27, 2015, 05:01:45 PM »
That's pretty good beating you gave that blade. I'm glad I didn't recognize it :) I liked the wacking it with the big stick after driving it in the log. Impressive. Seems to me you have your recipe down. Is that you new grind profile? A kit might be a fun project for me.

Creek

Yeah, thats the new profile. I am getting ready to do SIXFOOTER's blade, its the last of the bigger ones. I will take some pics of the blades together to show the reduction in size. It doesn't seem like a big change, but the in hand is night and day. Guys with big mitts (like SIXFOOTER) will appreciate the bigger version more, but for the rest of us this will be a much more comfortable handle.
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Offline Yeoman

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Re: Tip Torture Test
« Reply #13 on: January 28, 2015, 10:46:07 AM »
I'm impressed with the tip strength.
I don't think I own a knife that would put up with that kind of use.
I don't pry with the tip though. You only have to break three or six or so knives before learning that lesson.
One think I do to Mora's or other knives whose tips seem thin, is to "shark-tooth" the tip. I drag the back of the tip
over a file until it gets a micro drop point. I then smooth it out. Seems to work.
I don't think your knives would need that though!
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Offline kanukkarhu

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Re: Tip Torture Test
« Reply #14 on: January 29, 2015, 01:32:04 PM »
Cool vid. I think that's a great test of the tip (and edge) of that knife. I don't beat my blades anything near that. In fact, I'm not one of those "now let's go abuse this blade to see what it can do" kinda guys. Why anyone would abuse a fine piece of gear like that is beyond me.

I'd not hesitate to buy that knife, if I had the cash.


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Offline Quenchcrack

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Re: Tip Torture Test
« Reply #15 on: October 07, 2015, 07:20:56 PM »
I have known sword makers who use 1095 to water quench for a few seconds an then go into oil.  The water gets the steel under the pearlite nose and almost to the Ms temperature.  The oil cools it more slowly as the martensite forms.  Double tempering will get rid of most of the retained austenite or you can cryo treat it.  O1 is simpler to use.
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Offline PetrifiedWood

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Re: Tip Torture Test
« Reply #16 on: October 12, 2015, 11:15:44 AM »
I have known sword makers who use 1095 to water quench for a few seconds an then go into oil.  The water gets the steel under the pearlite nose and almost to the Ms temperature.  The oil cools it more slowly as the martensite forms.  Double tempering will get rid of most of the retained austenite or you can cryo treat it.  O1 is simpler to use.

I haven't tried water quenching knife blades, but all of the flint striker blanks I have are 1095. These I water quench, but every once in a while you will hear a "tink" sound when you quench one. Oil quenching 1095 strikers in mineral oil was too slow to get them hard enough to spark. It works fine for O1, though, of course. There are ways to slow the water down a bit (brine?) so it's still faster than oil, but not so violent as to create stress fractures. I wonder if plate quenching would be fast enough?

Oil floats on water. I wonder how a quench would work where a blade was lowered into water below the oil for a moment, then lifted back up into an oil layer? It's likely the bubbling would disturb the layers too much to be of use, but an interesting thought, anyway.

Offline Unknown

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Re: Tip Torture Test
« Reply #17 on: October 13, 2015, 05:31:12 AM »
Hi Red,
What if a blade failed in these test? does that make it a bad knife?

I can think of knives I have that might fail some of this. Making them thicker or bevels steeper doesn't necessarily make them better suited to what I need/want done.

Instead of looking at how a knife performs in oddball events like side wacking with a stick; how's about testing in things that knives really do? For instance a video of how to carve a divot rather than how to tear up a knife while making a divot in wood-just sayin( I know Im a dick)

what the heck am I saying-I have no idea how other people use knives or what they expect


Offline Red

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Re: Tip Torture Test
« Reply #18 on: October 13, 2015, 12:19:30 PM »
Hi Red,
What if a blade failed in these test? does that make it a bad knife?

I can think of knives I have that might fail some of this. Making them thicker or bevels steeper doesn't necessarily make them better suited to what I need/want done.

Instead of looking at how a knife performs in oddball events like side wacking with a stick; how's about testing in things that knives really do? For instance a video of how to carve a divot rather than how to tear up a knife while making a divot in wood-just sayin( I know Im a dick)

what the heck am I saying-I have no idea how other people use knives or what they expect


Well, for starters, I know how to carve a divot. You would be amazed how many people make a divot just like in that video. Improper technique that can cause failure of the blade will always come back on the maker. So, as a maker, you have to consider that people will do that, and that your blade will survive the task.

As for your "side whacking with a stick" comment; a blade that is tempered properly should be springy, so that when it baton's a piece of wood, it flexes with the wood and doesn't snap in half. That was merely a demonstration of a good temper on the blade, and that blade will withstand a good wallop without issue.

If a blade failed these tests, it wouldn't be a very good knife. I wouldn't want to carry a knife that wasn't tempered properly.

If you bought a knife from me, and the first time you took it out it broke.. you wouldn't be very happy with me, would you? You would expect a knife that you paid a couple hundred dollars for to be able to do certain tasks, like baton. I know I expect every knife I buy to do at least that much without failing. The tip is a little extreme, but like I said, there are a LOT of people that do it that way.

Just sayin..
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Offline Unknown

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Re: Tip Torture Test
« Reply #19 on: October 13, 2015, 09:46:31 PM »
Those are good answers Red.

of course I would baton my knife and if it broke i would be sad. mad probably too.

I could be overstating the severity of the torture test you showed. maybe i should rewatch it.

edit-with sound on I see you answered some of those questions. If I understood, the way you grind does not make the tip beefier because you are following the curve? what is the bevel angle even approximately?

« Last Edit: October 13, 2015, 10:35:18 PM by Unknown »

Offline Red

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Re: Tip Torture Test
« Reply #20 on: October 14, 2015, 06:40:49 PM »
Those are good answers Red.

of course I would baton my knife and if it broke i would be sad. mad probably too.

I could be overstating the severity of the torture test you showed. maybe i should rewatch it.

edit-with sound on I see you answered some of those questions. If I understood, the way you grind does not make the tip beefier because you are following the curve? what is the bevel angle even approximately?

That knife blade was ground at 14* per side, for a 28* bevel. The way I grind, it keeps the grind even all the way to the tip. Other guys grind laterally, just moving the blade straight across the platen, and when the edge curves up, the bevel does not stay as deep at the tip. Enzo knives are a good example of this. It gives you (theoretically) a stronger tip, but also a fatter one, not as pleasant to carve with as my tip.

notice how the bevel is very narrow at the tip:



Now, see how my bevel stays the same width from the plunge all the way to the tip:


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Offline Unknown

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Re: Tip Torture Test
« Reply #21 on: October 15, 2015, 02:15:16 AM »
Thank you for putting up with me Red. I apologize for my tone. It was misdirected.

 I went back through your gallery, your finished products are very eye catching.

At 28* ya couldn't really call it beefy I suppose except compared to a more dedicated carver. One of the questions you answered was when you said something like: Yall should know better.

That covers much of what I was trying to say originally. If you overbuild for abuse then you loose the "efficiency" that would make 99% of the real work needing done more effective and pleasurable. Have you ever tried 25*, or less.