Results 1 to 9 of 9

Thread: Trying to get a centerline for grinding with distal tapers and warps.

  1. #1

    Trying to get a centerline for grinding with distal tapers and warps.

    This is one of the biggest things I struggle with.

    Normally I could just go to a surface plate with a flat blank and scribe it out, but on the big kitchen knives it gets tricky for me.

    I usually do the distal taper before heat treat, and they never come out perfectly straight (I can get them straight enough to grind them OK). How would you do the centerline in this situation? I've been eyeballing my knives so far but there has got to be a more efficient method. In other WIP's I have seen, they have surface grinders and some fancy scribe setups, but that's a bit much for myself in this stage.

    The issue I'm having, putting it shortly, is that I don't have a straight enough blade to accurately scribe out.
    "Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." -Antoine de Saint-Exupery

  2. #2
    Are you on Facebook right now?

  3. #3

    Zwiefel's Avatar
    Join Date
    Jul 2012
    Location
    Little Rock, AR
    Posts
    2,538
    Im pretty stupid about this stuff but....Ive seen a micrometer used to measure thicknesx, calculate the centerline, then used to scribe it along the spine using the blade itself as the guide.

    HTH
    Remember: You're a unique individual...just like everybody else.

  4. #4
    Dan the problem I'm having is that I would need a perfect straight blade with uniform thickness to do that. My blades are relatively straight, good enough to grind down, but not enough to do an accurate line. I also have the distal taper so the it gets thinner towards the tip.

    I was talking to Cris about this and he gave me some good pointers, but if I'd really like to get a dead-on line I think I'll have to revise something in my methods.

    Maybe something I can do is leave the tang a little thicker than normal, grind that as flat and straight as I possibly can, and then go with a height gauge and surface plate. The idea would be to use the tang as the reference point.
    "Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." -Antoine de Saint-Exupery

  5. #5
    Quote Originally Posted by Don Nguyen View Post
    Maybe something I can do is leave the tang a little thicker than normal, grind that as flat and straight as I possibly can, and then go with a height gauge and surface plate. The idea would be to use the tang as the reference point.
    That will work great, if you can get the point to line back up with the tang out of the quench . Although, you could use your height gauge to help you get the point in line maybe.

    I don't know...it all seems too complicated lol. I like the 'grind the waves out of both sides and see what you've got to work with first' method better...but I know it goes against your engineering student sensibilities =p.

  6. #6
    You could find a center point any where along the blade by using your height gage and the surface plate. Scribe two parallel lines even with the sides of the blade and where they intersect is the center point. Do that at the point and the heel and one or more times in between. That should get you close enough and the rest is by eye.

    Hoss

  7. #7
    Quote Originally Posted by DevinT View Post
    You could find a center point any where along the blade by using your height gage and the surface plate. Scribe two parallel lines even with the sides of the blade and where they intersect is the center point. Do that at the point and the heel and one or more times in between. That should get you close enough and the rest is by eye.

    Hoss
    We talked about something similar Devin, only using a scribe that registers on the flat. I made a tool awhile back for that purpose...mark from one flat, then the other...in between the marks is the center. The height gauge would find the accurate center of the existing piece...but until he's ground the warps out, he won't know if the 'center' he found...is actually going to be 'the center' anymore lol.

    Honestly though, his current methods are turning out gorgeous knives! I'd almost say leave well enough alone...but I totally understand jiggling the handle of a process to try to make it more efficient.

  8. #8
    Senior Member
    Join Date
    Jun 2012
    Location
    Albany, NY
    Posts
    519
    Devin, if you do the distal taper AFTER the heat treatment, would that do anything to minimize stress and thereby warpage?

  9. #9
    Yes, anytime there is a variance in thickness there are added stresses in the quench.

    Hoss

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •