Spyderco Mule CPM M4

nozh2002

nozh2002

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This is test knife Spyderco made for steel junkies like me to have a taste of some exotic steel. This is second run with CPM M4. I just got it today and can not resist and rush to make some handle. It is full tang knife, but you have to make your own scales, which is even better for me - I can make whatever I want.

I want this time to experiment with leather. I take thick leather belt leather from Tandy - probably for really thick cowboys to keep their belly in place... There are stacked leather handles - but why not leather scales? This is what I want to try.

Spyderco-Mule-CPM-M4-001.jpg


I cut some rough scales and glue them to the tang with epoxy, trying not to drop epoxy on visible part of leather handle (almost successfully...). Then after epoxy set I dull all my Busse Game Wardens and Doziers and Yuna and few other knives cutting off leather around tang. Edge hit tang and of course any steel edge can not stand CPM M4, so I have to change many knives because to cut leather you need sharp blade...

But in result I have what I want - leather handle:

Spyderco-Mule-CPM-M4-002.jpg


Spyderco-Mule-CPM-M4-003.jpg


Spyderco-Mule-CPM-M4-004.jpg


Spyderco-Mule-CPM-M4-005.jpg


It is very light in comparison with wood of G1. It is also very warm - similar feeling as from stacker birch bark - at least until I add carnauba polish.

I decide to stop for today and finish it tomorrow. I will shape it bit more - make scales edges more round and I like to paint it with some dragon skin pattern then add carnauba polish to perfection...

Then I will sharpen it and test edge retention of couse...

Thanks, Vassili.
 
Good start. Very detailed like all your work. I can't wait to see what numbers you get comparing CPM M4 to some of the heavyweights you have already tested. Very much looking foreward to it. Joe
 
nozh2002 said:
.... I take thick leather belt leather from Tandy - probably for really thick cowboys to keep their belly in place...
Click to expand...
LOL!

Looking forward to your tests, Vassili. For all the pimping and pampering we saw with the first round of mules, I only recall one review here where the blade was actually used for some serious cutting. I'm sure we won't have to worry about you letting this one go unused!
 
Some parameters.

Blade length - 3 3/8"
Blade width - 1 1/4"
Blade thickness -7/64"
Handle length - 4 1/3"
Initial sharpness - 3 oz, no hair whittling

Blade has eye. There is no any reason to have it on fixed blade, but to be an eye. As I understand Indians (Native Americans) believed that eye on the blade will make it see what is going on around and so it will never cut it's owner.

Blade is traditional for Spyderco triangular flat ground from the spine, we may expect that it will be excellent slicer and cutter as many Spiderco knives.

Thanks, Vassili.
 
Hi Vassili,

handle looks comfortable and functional.

I like the Indian "eye" explanation. sounds good.

I'm looking forward to hearing how this M4 whittles hair when you're finished sharpening.

sal
 
Sal Glesser said:
Hi Vassili,

handle looks comfortable and functional.

I like the Indian "eye" explanation. sounds good.

I'm looking forward to hearing how this M4 whittles hair when you're finished sharpening.

sal
Click to expand...

Hi Sal,

Thanks, for opportunity to have this steel to taste!

Well, I can not promise - for example I was not able to do this with CPM S110V. But as I understand CPM M4 is not "abrasive" steel. Right now I am waiting for crnauba to dry - then I will start sharpening and edge retention testing.

Did you run it on your CATRA? What is your impression.

Thanks, Vassili.
 
Sal Glesser said:
Hi Vassili,

handle looks comfortable and functional.

I like the Indian "eye" explanation. sounds good.

I'm looking forward to hearing how this M4 whittles hair when you're finished sharpening.

sal
Click to expand...

It whittles very nice :D

Picture008.jpg
 
OK I finished handle:

Spyderco-Mule-CPM-M4-006.jpg


Spyderco-Mule-CPM-M4-007.jpg


Spyderco-Mule-CPM-M4-008.jpg


Spyderco-Mule-CPM-M4-009.jpg


This is experimetal one and I may need to work on few things, but I like it!

It is light - 3.92 oz. and have bright color - easy to find - good quality for working knife. And scale pattern hides few roughness I guess.

Now, I am going to resharpen it to whittle hair - as knifenut1013 already did.

Thanks, Vassili.
 
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Hmm I like the handle. You know, if you could use sandpaper to shape the leather eaiser next time Vassili. And if you don't like it, a quick soak in acetone and they are gone.:thumbup:
 
I use standard sandpaper wheel on Dremel. Next time I think I will need to use several finer sandpaper. But today I just rush to have it. to sharpen it and start testing edge retention.

Thanks, Vassili.
 
Nice Handle.

Let the testing begin.
 
Info on CPM M4 steel:

http://www.crucibleservice.com/eselector/prodbyapp/highspeed/rexm4.html

Carbon 1.30%
Manganese 0.30%
Silicon 0.30%
Chromium 4.00%
Vanadium 4.00%
Tungsten 5.50%
Molybdenum 4.50%
Sulfur 0.03%

In comparison with CPM S30V

C=1.45
Cr=14
Mo=2
V=4
N=0.2

From Spyderco site:

CPM-M4 is a high-speed, wear resistant, tool steel. It is non-stainless steel. Its high content of Molybdenum and Tungsten gives it a fine grain size, greater strength, hardness and toughness. It is a triple temper heat treat to make it as tough as possible without brittleness. The grinding combined with the triple temper heat treating process can cause warping up to 50 thousandths (.050) of an inch which is not enough to affect the performance of the knife. CPM-M4 will provide high edge retention and impact resistance with an Rc of 58-63, you’ll also find it’s relatively easy to sharpen.

Thanks, Vassili.

What is that 0.05 warping?
 
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I have found CPM M4 really takes to stropping with diamond paste. Without paste too, actually. So far it looks like one of the better all around steels you are testing up too this point. I was hesitant at first but I can say now I like it better than M2 as an all around steel, with better wear resistance, certainly better impact resistance and, from your testing, it looks like edge stability. Not bad at all.

You have an extrordinary collection of knives/steels that it would be difficult to match outside of labs that do research ( I'm not sure if the labs make their own knives or purchase them like you and I do). I really like your work and would like to say thanks for the time you have put into it

I would really like to get at the more obscure steels such as AUS8(W), and VG 10(W) which would be the basic AUS8A, and VG10 steels with typically small amounts of tungsten for grain refinement.I've only heard of these steels being used ( and rarely at that) in Sashimi knives. R2 is another powder mettalurgy steel that's proprietary and I've not seen any compositions released yet.

Then there are the ZDP4, and XYR7 steels. In Sandavik I'd like to test 19C27. Kind of expensive for what it is IMO.

By the way, for the heck of it if you ever want to try VG5 steel it's in the disposable blade "tigersharp" knives. If you ever want to test it I'll send it to you for testing. IMO, it's not as good as VG10, or even VG1. It's listed in the chart you have as being tougher than either though.

Regards Vassili, Thanjk you again for this excellent and comprehensive work. Joe L.
 
Beautiful job on the handle Vassili. Your attention to detail always impresses.

We are fortunate to have steel junky's of your interest and caliber sharing in our forum.

On the warpage, we found that some of the blades has a small warpage after heat treat and they could not be straightened. Given the small quantity of a one time run, we had to live with it. The length of the piece presents some heat treat challenges.

sal
 
No, I do no have any warpage - my blade is perfect in grind and everything.

Thanks, Vassili.
 
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