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Rex 45 sharpening and performance?

Discussion in 'Maintenance, Tinkering & Embellishment' started by Basedlarrydavid, Jan 19, 2019.

  1. Basedlarrydavid

    Basedlarrydavid Gold Member Gold Member

    Apr 17, 2018
    I kinda missed the train on Rex 45 when Spyderco dropped their sprints last year. The scale color wasn’t my thing and I had an aversion to non-stainless steels.

    Over the past couple of months, I’ve been using and sharpening M4 quite a bit while kicking myself for my fear of oxidation. Some of my best edges ever have come up on M4.

    So, talk to me a bit about your Rex 45 experiences.
  2. kwackster


    Dec 23, 2005
  3. DeadboxHero

    DeadboxHero Triple B Handmade Knives, Big Brown Bear Knifemaker / Craftsman / Service Provider

    Mar 22, 2014
    Harder, more stable, better edges then softer HRC M4. The higher hardness really improves the performance over M4.

    Would M4 perform the same or better with the same HRC? Maybe, thing is you don't get that option, it's one size fits all.

    So I'd choose the Rex 45 in a Spyderco if I had a choice.
    Basedlarrydavid and Blues like this.
  4. Basedlarrydavid

    Basedlarrydavid Gold Member Gold Member

    Apr 17, 2018
    Improved performance over M4? That’s a hell of a statement, my friend. One thing I really enjoy about M4 is the aggression in the edge, even when finished on sub-micron diamonds. Is Rex still getting there with the reduced vanadium carbide content? How do they compare in sharpening?

    Side note, I grabbed a PM2 yesterday, so I’ll be able to evaluate myself, but I’m curious nonetheless.
    Last edited: Jan 22, 2019
  5. mycough


    May 20, 2007
    Hell of a statement, and he can make it... The vanadium is only one small piece of the puzzle, the steel composition chart shows it to be chock full of tasty ingredients, so I think you will enjoy your "evaluation"...
    Basedlarrydavid likes this.
  6. Basedlarrydavid

    Basedlarrydavid Gold Member Gold Member

    Apr 17, 2018
    Greatly looking forward to it.
  7. Lipripper

    Lipripper Gold Member Gold Member

    Oct 15, 2017
    ...and I am pretty sure @DeadboxHero has a video somewhere of him cutting into brass rods with Spyderco M4 and Spyderco Rex 45, my apologies if you were already aware of it.
  8. Blues

    Blues Lapsed SuperMod / Cattle Knife Rustler Staff Member Super Mod

    Oct 2, 1998
    Lipripper likes this.
  9. samuraistuart

    samuraistuart KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 21, 2006
    Cutting through nails and brass rods is a function of geometry rather than steel type.
    DeadboxHero likes this.
  10. Lipripper

    Lipripper Gold Member Gold Member

    Oct 15, 2017
    Edit: Realizing I may have taken the previous post in the wrong light, and replied with a unwarranted comment.

    So yes, the video is meant as a resource for OP to take want he wants from it. I know the first time I saw it, it made me want to get Rex 45, but somehow my millie email never came in from BHQ until long after they were sold out. :(
    Last edited: Jan 23, 2019
  11. DeadboxHero

    DeadboxHero Triple B Handmade Knives, Big Brown Bear Knifemaker / Craftsman / Service Provider

    Mar 22, 2014
    It's the same geometry.
    mycough and Lipripper like this.
  12. Basedlarrydavid

    Basedlarrydavid Gold Member Gold Member

    Apr 17, 2018
    Yeah, if I came across as being argumentative or doubtful, it wasn’t my intention. I know how well-versed @DeadboxHero is on these things, which is why I was truly excited to hear Rex 45 being heralded (by someone who truly knows steel) as an improvement to M4, which is easily one of my favorite steels now.

    I’ve watched the video before, but maybe I need to run through it again. I was more or less just curious to know how it sharpens and performs in real world applications. Just sort of subjective opinions of the edge it takes and how it deals with cardboard, etc.
  13. Lipripper

    Lipripper Gold Member Gold Member

    Oct 15, 2017
    No, no, not you sir! All is good! I have the same curiosity about real world performance, but then again, I try to tell myself the steels I have are super enough, so I don't spend more money. Never works haha.
  14. sodak

    sodak Gold Member Gold Member

    Mar 26, 2004
    I keep telling myself the same thing! My collection just grows and grows! :D
  15. ejames13

    ejames13 Gold Member Gold Member

    Mar 30, 2015
    I've been working on reprofiling my PM2 in REX45 using the Edge Pro over the past few days. (I only like to sharpen for < 1 hour at a time to prevent fatigue.) I really like how this steel touches up on the Sharpmaker, and I was able to do that for a while to maintain sharpness. But it was time to put a nice fresh edge on this bad boy. So off to the Edge Pro it went.

    The 140 grit CKTG diamond plate made short work of the initial bevel setting at 15 dps, then that's where the real fun started. I took it to the 220 grit stock Edge Pro stone and it took far longer than I expected to clean up the scratches from the 140 diamond plate. Probably around an hour. Some of that was likely due to the fact that my angle was maybe 1/2 a degree or 1/4 shallower with the 220 stone, so I had to grind a little extra to get back to the apex. But man this stuff is hard. The 220 stone was loading up very quickly. Now usually it will keep cutting when that happens, but not with this steel. I was taking it to my flattening plate every few minutes to clean the metal from the stone and get to some fresh abrasive. I put it away for the night after I finally removed all the scratches and hit the apex on both sides of the blade with the 220. More later once I have time to take it through the remainder of the progression and finish it off.
  16. ejames13

    ejames13 Gold Member Gold Member

    Mar 30, 2015
    Following up on my previous post.

    I took my REX45 PM2 to the 400 grit stock EP stone last night, and I was having to refresh the surface of the stone even more frequently than with the 220. I noticed it would stop cutting before the stone was even loaded up. I think this was due to glazing over rather than loading. It was amazing how quickly this happened. I wasn't counting, but after maybe 20 passes or so I could feel the stone start to skate over the bevel. Took it to my 140 grit diamond plate for a surface refresh and I could immediately tell a difference in cutting efficiency.

    I chose not to eliminate the burr completely on the 400 grit stone, thinking I would clean it up on the 1000 grit. This was a grave mistake, as the 1000 grit stone had very little effect on the steel besides polishing it. I could not get the burr off completely with this stone. So I took it to a leather strop with 3um diamond compound. That cleaned up the burr pretty well. Edge will shave and push cut phone book paper, but still isn't quite where I hoped it would be. Perhaps I'll finish at 400 grit next time and no strop.

    I'm wondering if anyone else has any experience sharpening REX45 on the EP stock stones? I'm not an EP expert, but I have sharpened other steels on it (VG-10, Vtoku2, cheap stainless) without any issues. My suspicion is that the steel is so hard it's difficult for the EP stones to cut.
  17. PeterS84

    PeterS84 Sharpening addict, collector of "super steels" Platinum Member

    May 9, 2018
    EP stock stones are made from AlOx, which doesn't tend to cut the CPM steels especially well. Once you start getting into high hardness and PM steels, you really need to be looking at diamond, CBN, or SiC stones if you want to cut them efficiently. Not to say you can't do it with the stock stones but it will take much longer and probably not give you as good of a result.
    brando555 likes this.
  18. DaveDM


    Dec 21, 2017
    Any update on the progress?
  19. ejames13

    ejames13 Gold Member Gold Member

    Mar 30, 2015
    I haven’t taken it back to the EP since that post. I cut some cardboard etc which dulled the edge slightly. Microbeveled on the sharpmaker at 40 deg and stripped with the 3um diamond again. Edge is as good if NT better than it was coming off the 1000 grit EP stone. I really like how responsive this steel is to the Spyderco ceramics, despite it being so hard.
    DaveDM likes this.
  20. brando555

    brando555 Gold Member Gold Member

    Sep 26, 2018
    Finally got around to sharpening my Para 3 yesterday on the EP. The Rex 45 wasn't as hard to sharpen as I thought it would be, but it definitely took a little more work than something like s30v.

    Started out with a 150 grit Venev to set the bevel to an even 15° all the way from heel to tip, then moved on to 400, then 800. After 800 I went to my 800 grit Boride SiC stone to get as many of the diamond scratches out as I could, this part actually took a bit of work, I had to keep wetting the stone to keep it from loading up.

    After I was satisfied with the 800 grit SiC stone, I went to the strops loaded with 1 micron and .5 micron diamond respectively. The strops brought out a nice semi polished finish on the edge with plenty of bite. I thought about using some polish tapes but decided against it. I think I may buy a 1200 grit SiC to see how well it brings the polish up instead next time.

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