Spyderco Forums

Posted: **Fri Feb 10, 2023 11:28 am**

Josh Crutchley wrote: ↑
Thu Jan 05, 2023 12:44 pm
I had the pleasure of testing a blade in T15 from Bluntcut Metalworks. I was really impressed with how easy it sharpened, kinda reminded me of Maxamet. It had a custom heat treatment but I would need to try some other T15 to understand the differences.

??? I thought Maxamet had a reputation for being hard to sharpen? I don't have any experience with that steel, but I was able to bring my REX76 Mule back to a keen edge after whittling away at dry branches for ~7-8 hours. It felt like "stones on glass" working it in the Worksharp fixed angle system.

Posted: **Fri Feb 10, 2023 2:29 pm**

bobartig wrote: ↑
Fri Feb 10, 2023 11:28 am

??? I thought Maxamet had a reputation for being hard to sharpen? I don't have any experience with that steel, but I was able to bring my REX76 Mule back to a keen edge after whittling away at dry branches for ~7-8 hours. It felt like "stones on glass" working it in the Worksharp fixed angle system.

It might but I've never had a problem with it, S110V on the other hand gave me issues awhile back.

Posted: **Sun Feb 26, 2023 9:40 am**

Bolster wrote: ↑
Wed Jan 04, 2023 6:58 pm
Is your "Mule Sense" tingling for the T15 mule? Have any of you experienced T15 in another blade? What do we know about T15...the good, bad & ugly? Spyderco says it's an end mill steel, so that means I need one. Maybe I can chuck it in my mill and use it to drill tapered holes! (Not.)

Use some bolts and metal bits to mount it horizontally and slice meat with it.

Posted: **Sun Feb 26, 2023 9:51 am**

For edge durability, I like the brass rod torture the Big Brown Bear does. Or the ironwood torture that Phil does. Dig in and twist to stress the edge. Those show edge roll and chipping very well with almost no risk of breaking the knife.

Posted: **Sun Feb 26, 2023 11:15 am**

Anyone have like a one-line description, or mnemonic for keeping T15 and 15V straight in their heads?

Like, "T15 is x, where as 15V is y", where x and y are properties of those respective steels. I'll try to get them both, but for now I can't keep them straight in my head.

Posted: **Sat Mar 04, 2023 9:26 am**

legOFwhat? wrote: ↑
Wed Feb 08, 2023 12:52 pm
Where you at T15?

My spydie senses are tingling…. Think it has to be soon

Posted: **Sat Mar 04, 2023 9:57 am**

standy99 wrote: ↑
Sat Mar 04, 2023 9:26 am

legOFwhat? wrote: ↑
Wed Feb 08, 2023 12:52 pm
Where you at T15?
My spydie senses are tingling…. Think it has to be soon

It's gonna be a good year for us MuleTeam junkies! T15 and 15v along with the Aeb-l.

Posted: **Sat Mar 04, 2023 12:14 pm**

standy99 wrote: ↑
Sat Mar 04, 2023 9:26 am

legOFwhat? wrote: ↑
Wed Feb 08, 2023 12:52 pm
Where you at T15?
My spydie senses are tingling…. Think it has to be soon

But mine has been tingling for months. I think my tingler needs a recalibration. Do tingler units wear out with too much anticipation?

Posted: **Sat Mar 04, 2023 12:18 pm**

bobartig wrote: ↑
Sun Feb 26, 2023 11:15 am
Anyone have like a one-line description, or mnemonic for keeping T15 and 15V straight in their heads? Like, "T15 is x, where as 15V is y", where x and y are properties of those respective steels. I'll try to get them both, but for now I can't keep them straight in my head.

How about:

T15 is Tougher (relatively; perhaps around 8 ft lbs cf to 15V's 3-4 ft lbs)

15V is crammed with Vanadium (15V is about 15% vanadium...cf to T15 which is about 5% vanadium).

Posted: **Sat Mar 04, 2023 12:28 pm**

A fun graphic with PM T15 making an appearance (which also shows why PM M4 is such a good knife steel):

Posted: **Sat Mar 04, 2023 2:40 pm**

bobartig wrote: ↑
Sun Feb 26, 2023 11:15 am
Anyone have like a one-line description, or mnemonic for keeping T15 and 15V straight in their heads? Like, "T15 is x, where as 15V is y", where x and y are properties of those respective steels. I'll try to get them both, but for now I can't keep them straight in my head.

The easy thing to remember about 15V is that it's about 15% Vanadium.

T15 is about Twelve percent Tungsten.

Posted: **Sat Mar 04, 2023 8:39 pm**

Bolster wrote: ↑
Sat Mar 04, 2023 12:28 pm
A fun graphic with PM T15 making an appearance (which also shows why PM M4 is such a good knife steel):

do you know what "red hardness" represents on that graph? idk the term, but these are interesting data

Posted: **Sun Mar 05, 2023 12:14 am**

bleasure wrote: ↑
Sat Mar 04, 2023 8:39 pm

Bolster wrote: ↑
Sat Mar 04, 2023 12:28 pm
A fun graphic with PM T15 making an appearance (which also shows why PM M4 is such a good knife steel):
do you know what "red hardness" represents on that graph? idk the term, but these are interesting data

I think it means hardness at high temperature, as for a metal cutting bit. Of no interest for a pocket knife blade, unless you are in ****.

Posted: **Sun Mar 05, 2023 5:29 pm**

Bolster wrote: ↑
Sun Mar 05, 2023 12:14 am

bleasure wrote: ↑
Sat Mar 04, 2023 8:39 pm

Bolster wrote: ↑
Sat Mar 04, 2023 12:28 pm
A fun graphic with PM T15 making an appearance (which also shows why PM M4 is such a good knife steel):
do you know what "red hardness" represents on that graph? idk the term, but these are interesting data

I think it means hardness at high temperature, as for a metal cutting bit. Of no interest for a pocket knife blade, unless you are in ****.

I wonder if it will enable it to be sharpened by belt grinder with less threat of overheating....

Posted: **Tue Mar 07, 2023 9:25 am**

I really hope this Mule is coming soon. I'm supposed to make my best build ever for a fellow forumite, and I'm starting to feel guilty for having him wait this long for the CPM-T15 Mule to be available !

Posted: **Thu Mar 09, 2023 7:45 pm**

RamZar wrote: ↑
Sat Mar 04, 2023 6:02 pm
The following New Models were Announced 5+ Months Ago in various Reveals but not yet Delivered:

...

Mule Team CPM-REX-T15 MT34 (Taiwan) - Reveal 10 (JUN 2022)
...

Posted: **Wed Mar 15, 2023 4:36 am**

Time keeps on slipping slipping into the future.

The flock needs a new member.

Posted: **Wed Mar 15, 2023 7:31 am**

legOFwhat? wrote: ↑
Wed Mar 15, 2023 4:36 am
Time keeps on slipping slipping into the future. The flock needs a new member.

Just swapped a CPM S45VN for a CPM 4V with a member so have a new steel to play with…

Posted: **Wed Mar 15, 2023 9:16 am**

standy99 wrote: ↑
Wed Mar 15, 2023 7:31 am

legOFwhat? wrote: ↑
Wed Mar 15, 2023 4:36 am
Time keeps on slipping slipping into the future. The flock needs a new member.
Just swapped a CPM S45VN for a CPM 4V with a member so have a new steel to play with…

Ooo the 4v mule is one of my favs! Mines on hold for a handle as well

Posted: **Mon Mar 20, 2023 5:42 am**

It's interesting to me that given how similar T15 and Z-Max are, that Z-Max is so much higher on Larrin's edge retention chart. Given their composition and micrographs, it seems like their carbide content is pretty similar...

Z-Max

CPM-T15

Though they did have different hardness levels...

Larrin also mentions that his predictive TCC and actual TCC for Z-Max varied quite a bit, and offered this supposition...

Z-Max did a bit better than predicted when looking at the edge retention predictions based on carbide content. The dataset used for those predictions had very few high speed steels which is also the case with this dataset. It could be that the M6C (tungsten/molydenum carbides) present in high speed steels contribute more to edge retention than previously found. This could indicate that M6C hardness measurements on the upper end are more accurate (1800 vs 1400 Hv).

I was playing around with the TCC regression formulas and various carbide percentages and worked back to something that seems like it matches his data for T15

-157 + 15.8*65.5 – 17.8*30+ 11.2*0 + 14.6*0 + 26.2*9 + 9.5*9 + 20.9*0 + 19.4*0 = 665 TCC

That assumes a total carbide volume of 18%, half Vanadium and half Tungsten carbides.

It seems like the biggest difference is the large amount of Molybdenum, but if Mo and W both form M6C carbides, I wonder why it seems that the carbides in Z-Max seem significantly harder than those of T15. Because even the 3 point HRC difference doesn't seem to account for the wildly different TCC results, but harder carbides would--particularly higher Vanadium carbides.

I searched for mentions of Molybdenum on his blog to see if I could find something that might explain and found the article about tool steel that kind of seems to suggest that a combination of Mo and W leads to higher concentration of vanadium carbides such as with M2 and M4, but at that point I'm just taking a shot in the dark.

One particularly interesting part was this...

Also, because molybdenum is approximately half the atomic weight of tungsten, tungsten can be replaced by only half of the amount of molybdenum.

Makes me wonder if that somehow enables more Vanadium to form carbides by tying up less carbon into M6C carbides.

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