Fit and Finish question

Discussion in 'New to Knifemaking' started by wmhammond, Apr 6, 2017.

  1. wmhammond

    wmhammond Well-Known Member

    I'm not that new to knifemaking nor am I new to this site - been here about 4 years, but after spent 4 hours in my shop this morning I quit in disgust and felt like I had never made a knife before. My problem, a hidden tang knife with a complex (three layers) double guard (top and bottom). Built the blade with the hidden tang - no problem. Squared the shoulders on the blade - no problem. Built the initial piece of the guard with the slot - no problem. Peened and ground the guard slot and got a perfect fit between the guard and the blade shoulders. Added a 1/16" slice of brass and a 1/2" slice of more A2 (the initial guard was A2 also) to the guard. Drilled and pinned the three pieces of the complex guard together and peened the pins and ground it to rough shape - beautiful tight fit. Finished the face of the guard. Got my handle material (Wych Elm Burl) rough cut and drilled for the tang - it all rough fit perfectly. I glued it up and let it cure overnight - this morning it was ready to start finishing the handle to the guard. Now the problems started. First step - flattened the sides of the handle to the sides of the guard on my disk grinder - perfect, sides were square to the top and bottom of the handle. Next I drew out and rough shaped the profile of the handle so now I've got a square handle and a square guard with a great profile. I knew I wanted the sides of the handle to have a slight convexed shape and the corners of the handle to be slightly rounded. So I started working on convexing the sides of the handle and the guard on my 2 X 72 grinder and things went south. First the wood of the handle started eroding away faster than the guard. When I changed the angle to correct that the belt edge started eating into the middle of the handle. My handle and guard were big enough to allow for this so I went to my Fordom Rotary tool to fix these errors. Ha! Fat Chance! The rotary tool made the problem between the guard and the handle worse and didn't help the handle much either so I went back to the bench and got out the files and sandpaper and pretty much got everything back to square and true - almost. On closer inspection I noticed that I had filed into one of my pins on the guard so the knife was ruined and so, probably, was my state of mind. But I pressed on trying to use this disaster as a learning experience, Ha! Fat Chance! I started again with a much finer grit belt and a slower speed on my grinder. Same thing happened again only it happened slower because of the slower speed and the lesser grit but same result. I quit in disgust and came in the house to watch the Masters and do what I always do when I can't figure something out - get on Knifedogs.com. Obviously, I have no clue how to do this operation. Could several of you guys tell me whats wrong with my process and make some suggestions to get me back on track. Thanks,

    Wallace
     
  2. busted knuckles

    busted knuckles Well-Known Member

    It sounds like the problem is that the wood is grinding away faster than the metal?
    When I'm experiencing that problem I ignore the wood and focus on grinding the metal, the wood will follow. I'll keep a slight angle away from the wood, just a bit.
    Don't know if I'm explaining this very well! But yes, it's kinda tough to grind a hard and soft material together.
    Good luck!
     
  3. EdCaffreyMS

    EdCaffreyMS Forum Owner - Moderator

    ^That would be exactly my advice too. I have to use that same technique, even with guard materials as soft as brass or Nickel Silver. The issue becomes more pronounced with harder materials (in this case the A2)..... whenever you create a composite guard, the overall guard will only grind down as fast as the hardest material.

    In my case, I always us a slack belt attachment, and "rough" out the shape of the guard with a 50 or 120 grit belt... either in a "X" weight backing. The "X" weight is stiff, and resists following the contour(s), and helps avoid digging into the softer handle material (but you still have to concentrate and be very careful if the belt makes contact with the handle material. I grind to the point where I leave only enough material to be "cleaned" up with a 220 through 600 belt.
     
  4. jkf96a

    jkf96a Well-Known Member

    I agree, I try and keep the belt mostly on the guard, and let the wood do its own thing. I also shape the handle on the platen vertically, with the tip of the knife up, so that the guard is the first thing the belt hits. I only run the belt perpendicular to the handle late in the process, with fine belts.

    Regarding grinding into your guard pins, see if you can move them further in toward the tang next time. They don't have to be anywhere specific, they just keep things in line. I try and put mine on parts of the guard I won't be grinding on much.
     
  5. busted knuckles

    busted knuckles Well-Known Member

    Jason, I'm going to try your vertical technique, I can see that working well in some situations.
     

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