Rex 45 sharpening

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driftingfir
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Rex 45 sharpening

Postby driftingfir » Sun Sep 13, 2020 5:02 pm

I've got a text 45 manix lw coming tomorrow. I've never had rex 45 and wanted to know how it sharpens up compared to similar steels. Thx

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Re: Rex 45 sharpening

Postby Cycletroll » Sun Sep 13, 2020 5:54 pm

Carbide rich- you're gonna want CBN or diamond stones. You'll get the greatest working edge with a more coarse edge finish. 600 grit seems about right.

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Ankerson
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Re: Rex 45 sharpening

Postby Ankerson » Sun Sep 13, 2020 6:04 pm

driftingfir wrote:
Sun Sep 13, 2020 5:02 pm
I've got a text 45 manix lw coming tomorrow. I've never had rex 45 and wanted to know how it sharpens up compared to similar steels. Thx

Sharpens pretty easy really and due to the higher hardness the burr is easy to remove.

About like S30V really give or take from what I have experienced.

Nothing really special needed to sharpen it, I have used SIC and ceramics on it without issues.

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Sharp Guy
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Re: Rex 45 sharpening

Postby Sharp Guy » Sun Sep 13, 2020 6:54 pm

Ankerson wrote:
Sun Sep 13, 2020 6:04 pm
driftingfir wrote:
Sun Sep 13, 2020 5:02 pm
I've got a text 45 manix lw coming tomorrow. I've never had rex 45 and wanted to know how it sharpens up compared to similar steels. Thx
Nothing really special needed to sharpen it, I have used SIC and ceramics on it without issues.
I don't think I've reprofiled any of my REX 45 models but I have touched up a few up with the Sharpmaker ceramics. Seems pretty easy to bring the edge back. I have reprofiled several HAP40 models and SiC works fine. I can't imagine REX 45 would much more difficult even though it's run harder
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SubMicron
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Re: Rex 45 sharpening

Postby SubMicron » Sun Sep 13, 2020 7:03 pm

Compositionally there's no reason REX-45 necessarily requires diamond or CBN. It's almost analogous to HAP40, a high end Japanese cutlery steel that is traditionally sharpened without diamonds or CBN.
Screenshot_20200913-194711_Knife Steel Compositions.jpg
The reason why I find diamonds to be advantageous while sharpening REX-45 is due to the high speed at which they cut which minimizes mistakes. I'll use them to set the edge bevel, or especially to reprofile. REX-45 has very high hardness which can cause some stones to struggle to cut as the steel skates over the top.

On REX-45, my Shapton Glass ceramics achieve a much higher level of sharpness than my DMT and Atoma diamond plates. For that reason, I'll use them to finish, or otherwise just use them to touch up the edge with moderate and then extremely light pressure.

Using ceramics whenever possible helps prevent over sharpening. REX-45 is one of the few super steels that allows you to get away with it.
Last edited by SubMicron on Sun Sep 13, 2020 7:09 pm, edited 2 times in total.

driftingfir
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Re: Rex 45 sharpening

Postby driftingfir » Sun Sep 13, 2020 7:07 pm

I've sharpened k390 with no problem, is it similar to that

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SubMicron
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Re: Rex 45 sharpening

Postby SubMicron » Sun Sep 13, 2020 7:15 pm

driftingfir wrote:
Sun Sep 13, 2020 7:07 pm
I've sharpened k390 with no problem, is it similar to that
If you can sharpen K390, you'll definitely be able to sharpen REX-45.

The two have different personalities. K390 introduces sharpening difficulty from carbide type and volume whereas REX-45 brings difficulty from high hardness. Both are no problem with the right abrasives.

K390 takes a more aggressive edge with all of its carbides whereas REX-45 will take an extremely fine edge or otherwise will allow you to install a very aggressive edge if you want.

K390 is basically diamond/CBN mandatory whereas REX-45 is more cooperative with traditional high quality abrasives.

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SubMicron
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Re: Rex 45 sharpening

Postby SubMicron » Sun Sep 13, 2020 7:17 pm

Americanized Voodoo Steel!!!

I love REX-45

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Ankerson
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Re: Rex 45 sharpening

Postby Ankerson » Sun Sep 13, 2020 7:20 pm

SubMicron wrote:
Sun Sep 13, 2020 7:15 pm
driftingfir wrote:
Sun Sep 13, 2020 7:07 pm
I've sharpened k390 with no problem, is it similar to that
If you can sharpen K390, you'll definitely be able to sharpen REX-45.

The two have different personalities. K390 introduces sharpening difficulty from carbide type and volume whereas REX-45 brings difficulty from high hardness. Both are no problem with the right abrasives.

K390 takes a more aggressive edge with all of its carbides whereas REX-45 will take an extremely fine edge or otherwise will allow you to install a very aggressive edge if you want.

K390 is basically diamond/CBN mandatory whereas REX-45 is more cooperative with traditional high quality abrasives.

Haven't seen a steel yet that I couldn't sharpen with high quality SIC stones.

I have seen almost all of them over the years.... Including S125V and MAXAMET....

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Re: Rex 45 sharpening

Postby GarageBoy » Sun Sep 13, 2020 7:26 pm

viewtopic.php?f=2&t=80749

Also some nice advice here

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SubMicron
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Re: Rex 45 sharpening

Postby SubMicron » Sun Sep 13, 2020 7:44 pm

Ankerson wrote: Haven't seen a steel yet that I couldn't sharpen with high quality SIC stones.

I have seen almost all of them over the years.... Including S125V and MAXAMET....
You're post is missing the final ingredient that allows you to get get it done with high quality non-diamond abrasives, and that is experience. I'm assuming that were talking freehand sharpening.

The ability to consistently hold the edge angle with accuracy is extremely important, obviously, but especially with abrasives that dont cut as efficiently. Otherwise you're stacking micro mistake on top of micro mistake with the increase in number of passes. Experience matters a lot.

The amount and the effect of carbide tearout will be endlessly debated because the number of variables involved. What matters is if your content with the result, or not.

Its also worth mentioning that SiC does cut even the hardest ceramic / synthetic sapphire. This would clearly give it an advantage over ceramics while sharpening.

The beauty of REX-45... well aside from the very high hardness, edge stability, wear resistance, and fine edge holding abilities, is that you can use ceramics without worrying about carbide tearout. SiC definitely would work great as well.

SiC actually is an abrasive that I'm interested in exploring. Which would you reccomend?

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Ankerson
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Re: Rex 45 sharpening

Postby Ankerson » Sun Sep 13, 2020 8:33 pm

SubMicron wrote:
Sun Sep 13, 2020 7:44 pm
Ankerson wrote: Haven't seen a steel yet that I couldn't sharpen with high quality SIC stones.

I have seen almost all of them over the years.... Including S125V and MAXAMET....
You're post is missing the final ingredient that allows you to get get it done with high quality non-diamond abrasives, and that is experience. I'm assuming that were talking freehand sharpening.

The ability to consistently hold the edge angle with accuracy is extremely important, obviously, but especially with abrasives that dont cut as efficiently. Otherwise you're stacking micro mistake on top of micro mistake with the increase in number of passes. Experience matters a lot.

The amount and the effect of carbide tearout will be endlessly debated because the number of variables involved. What matters is if your content with the result, or not.

Its also worth mentioning that SiC does cut even the hardest ceramic / synthetic sapphire. This would clearly give it an advantage over ceramics while sharpening.

The beauty of REX-45... well aside from the very high hardness, edge stability, wear resistance, and fine edge holding abilities, is that you can use ceramics without worrying about carbide tearout. SiC definitely would work great as well.

SiC actually is an abrasive that I'm interested in exploring. Which would you reccomend?


NOPE, I am not talking about freehand sharpening..... I don't bother with it much any more except for quick touchups.... Stropping or Ceramic rods...

I use Congress Mold Master SIC stones on my Edge Pro.... They are VERY hard SIC with very little filler, very high quality...

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Sharp Guy
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Re: Rex 45 sharpening

Postby Sharp Guy » Sun Sep 13, 2020 9:31 pm

+1 on the Moldmasters. Thanks to discussions on here I think I now have 4 sets in two different widths and thickness. Reasonably priced too

https://www.congresstools.com/catalog/c ... ory/?id=27
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Re: Rex 45 sharpening

Postby Bloke » Sun Sep 13, 2020 9:57 pm

Ankerson wrote:
Sun Sep 13, 2020 8:33 pm

I use Congress Mold Master SIC stones on my Edge Pro.... They are VERY hard SIC with very little filler, very high quality...
Hey Jim, I generally sharpen everything with SiC and only go to Diamond or CBN if a particular steel is frustrating me.

Congress don't ship to Oz. I could call on a favour form a mate and have him send some but how do they compare to the Russian Gitomatic SiC?
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Re: Rex 45 sharpening

Postby JMM » Sun Sep 13, 2020 10:13 pm

driftingfir wrote:
Sun Sep 13, 2020 7:07 pm
I've sharpened k390 with no problem, is it similar to that
Yes it is . . . if you can sharpen K390 you'll do just fine with Rex45

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Ankerson
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Re: Rex 45 sharpening

Postby Ankerson » Sun Sep 13, 2020 10:26 pm

Bloke wrote:
Sun Sep 13, 2020 9:57 pm
Ankerson wrote:
Sun Sep 13, 2020 8:33 pm

I use Congress Mold Master SIC stones on my Edge Pro.... They are VERY hard SIC with very little filler, very high quality...
Hey Jim, I generally sharpen everything with SiC and only go to Diamond or CBN if a particular steel is frustrating me.

Congress don't ship to Oz. I could call on a favour form a mate and have him send some but how do they compare to the Russian Gitomatic SiC?

I think the Mold Masters are better, I use the 320 and 400 grits the most...

320 for reprofiling and sharpening and the 400 to finish.


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