"Use Belts Like They Are Free" - OK, now I **GET** it....

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by Cushing H., Oct 14, 2020.

  1. Cushing H.

    Cushing H. Gold Member Gold Member

    Jun 3, 2019
    I have been working in grinding a beautiful damascus blank that WEO created for me (Chinese cleaver style). It came out of the forging process slightly curved spine-to-edge (understandable!) ... so my task has been to grind on each side to create straight bevels.

    Well, working with a 60 grit ceramic belt, I had been struggling with a few last spots that were not grinding out (actually the surrounding metal of those spots on the concave side). Making progress, but slowly, and needing to cool the blade very often.

    WELL, "prepared" for this I lined up a new 60 grit ceramic belt and thought "ok ... so how different could this be?....."

    Oh. My. God.

    A shower of sparks, and two passes later (and no burned fingertips) the entire face I had been working the last hour to flatten was ..... flat, and uniformly ground (in terms of texture). the rest of the work (on the other side) went just as fast and easy.

    Now I get it.

    I'm going to stop typing this post, and sign in to my appropriate supplier's website and order more 60 and 120 grit belts.....
     
  2. Richard338

    Richard338 Gold Member Gold Member

    May 3, 2005
    I'm sorry, you still don't quite get it...you need 36 grit!!
    For me a fresh 36 is everything you described and more. I think I'm actually more accurate with it as I can be smooth and relaxed, light pressure.
     
  3. Cushing H.

    Cushing H. Gold Member Gold Member

    Jun 3, 2019
    Lol. I almost put into the post something like “this is almost enough to get me to try 36 grit ... but I still fear them”. Not on this blade (it’s a special one to take chances on) ... but perhaps I am inching my way there...
     
  4. Richard338

    Richard338 Gold Member Gold Member

    May 3, 2005
    Yeah, I wish I got there sooner. I used to spend a lot of time at 120 afraid to make mistakes. It's hard to know what would have happened if I tried 36 then. I feel like my grinding has improved over time and boy do I like the 36 now. I take it nearly all the way and just do a couple smoothing passes at 60 and 120 etc at the end.
     
    David Mary likes this.
  5. N.W. Gean

    N.W. Gean KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    153
    Oct 10, 2018
    So far, I've had to learn that lesson about 5 or 6 times. 96% of the time, my bevel issues go away with a fresh belt.
     
  6. razor-edge-knives

    razor-edge-knives Moderator Moderator Knifemaker / Craftsman / Service Provider

    Apr 3, 2011
    Yeah it makes a HUGE difference, at any grit level.

    But yeah, you need to go down to 36 grit after you get the muscle memory developed... I was able to rough grind these 2.5" blades pre-ht @ 50% power with a 36 grit 984f belt... I could get over 25 blades per belt.

    [​IMG]
     
  7. Flatlander bowie

    Flatlander bowie

    18
    Jun 23, 2020
    I do all my grinding on a 2x48 Kalamazoo. 1 speed, all of it. I started with 36 grit belts so maybe I never new to be scared, but they do require a little bit of touch. I only use 3 belts currently. 36, 120, 240. 36 grit last me about 5 4.5"ish hunters on AEB-L. 120s last about the same, but the 240 I grab a new belt for every blade. I use em for scales and wood after that.
     
  8. A.McPherson

    A.McPherson KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jan 27, 2012
    You know, I've found that the more "afraid to make mistakes" I am, the more mistakes I make...
    You just gotta get in there and do it. If you screw it up, try again! Steel is pretty cheap all things considered.
     
    oldmanwilly, weo and Richard338 like this.
  9. Randydb

    Randydb Basic Member Basic Member

    Sep 27, 2014
    Very cool thread and very true. Running through 220, 400, 600 on 12 AEBL heat treated student blades last weekend before my grinder went into the container. Every time a new belt went on I was amazed at how quickly and easily the next few blades went. And then it was taking more passes and patience to get the next few blades done at that grit. With 400 and 600 I was getting about 4 blades done easily and 2 with diminishing returns before I changed the belt for a fresh one.

    Thing is, I get that fresh belt on and suddenly I am using relaxed pressure, smooth passes, getting a nice flat surface and the previous grit scratches are going away fast. Not having to fight it. And then 10 minutes later I am trying to save the belt and get one more blade out of it with much frustration.

    An added question. I was spraying the blades with the blue layout solution through 400 grit so I could see and make sure I could see and get rid of all the previous grit scratches. I decided to skip the layout solution for 600 and I think I still did fine and could see the previous grit scratches without it. Am I on the right track here? Or will I discover I missed some later?
     
    razor-edge-knives likes this.
  10. john april

    john april KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Feb 27, 2006
    yes, you are on the right track. i think i can see the previous grit scratches too, but i still blue the blade between grits.
     
  11. Cushing H.

    Cushing H. Gold Member Gold Member

    Jun 3, 2019
    I have not tried that. Good idea...
     
  12. Daniel Fairly Knives

    Daniel Fairly Knives Full Time Knifemaker Moderator Knifemaker / Craftsman / Service Provider

    Jan 9, 2011
    I learned to grind ""by hand" (about 4000 of them) and I think everyone should or you will be very limited... but if you want to grind knives fast and make belts last forever do it at a high belt speed and with a sled style jig. I'm about to add a lever to mine so I can add more pressure.

    But yes, I'll use a new belt for about 10 passes and toss it into the horizontal grinder belt pile when I need to. VSM belts are great for this.
     
    Flatlander bowie, SBuzek and Natlek like this.
  13. weo

    weo KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Sep 21, 2014
    I like this!!!:thumbsup::) I might just have to edit a version of this into my signature line....
    BAM!!!! You hit the nail on the head here, Randy. I think this is the whole issue right here.

    PS - Great thread, Cush. Thanks for posting this reminder. (and I'm starting to feel a little better about that billet now:rolleyes:)
     
  14. Cushing H.

    Cushing H. Gold Member Gold Member

    Jun 3, 2019
    You are welcome! And .... the billet is doing great - it is ME I am worried about (in terms of making a mistake...... :) )
     
    razor-edge-knives likes this.
  15. PEU

    PEU Gaucho Knifemaker Knifemaker / Craftsman / Service Provider

    884
    Aug 6, 2006
    I'm interested to see this lever idea!

    Pablo
     
  16. Dominick Maone

    Dominick Maone

    76
    Oct 14, 2018
    Why do we use ceramics with light pressure if they work better for hard pressure? I use light pressure and it seems to remove material very well, but arent' ceramics meant to be used hard? Are we wasting our money with ceramics?
     
    Ken H> likes this.
  17. PEU

    PEU Gaucho Knifemaker Knifemaker / Craftsman / Service Provider

    884
    Aug 6, 2006
    For manual work its very difficult to maintain constant and hard pressure. I've seen machine used ceramic belts and they last almost to the cloth, mine always glaze way before all the abrasive is gone.
    Tried to dress them with diamond tip, but saw no improvements.

    Pablo
     
  18. Stacy E. Apelt - Bladesmith

    Stacy E. Apelt - Bladesmith ilmarinen - MODERATOR Moderator Knifemaker / Craftsman / Service Provider

    Aug 20, 2004
    Ceramic belts dress best with lots of pressure and hard surface dressing tool to fracture the grit.
    First, clean the belt well with a rubber stick. Then, with the grinder running at full speed, press HARD with the end of a hardened steel bar. Another good dressing tool is an old Carborundum grinding wheel.
    To make a dressing bar, harden a piece ofv1/4"X2"X12" 10XX flat stock and temper it at 350°F.

    Ceramic belts need speed, pressure, and power to get their best features. Run the grinder at full speed. Press hard on the blade. Use a grinder with enough power not to bog or stall.
     
    razor-edge-knives likes this.
  19. Natlek

    Natlek

    Jun 9, 2015
    I believe that he mean on something like this , PEU .............on 50 sec.
     
    Last edited: Oct 15, 2020
    Daniel Fairly Knives and PEU like this.
  20. Daniel Fairly Knives

    Daniel Fairly Knives Full Time Knifemaker Moderator Knifemaker / Craftsman / Service Provider

    Jan 9, 2011
    Yes that is a great example. I remember some old video with Burr-King grinders set up this way in a small factory. I think it would be great for initial hogging and more.
     

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