Custom Folding Knife

Introduction to Centering Your Folding Knife

Introduction to Centering Your Folding Knife

All of us have had the problem... you’ve just finished making a folder (3 days to 3 years later) … to find that it’s not centered! Frustrating is an understatement. I’m going to break down a few key things to look for/do that will help you along the way to being centered… only with the folder, not in your life because let’s face it… you’re a bit mmm- eccentric if you make folding knives.

What is Centering:

Centering is one of those things when it comes to knife collecting that many are very passionate about. Over the years I’ve had many compliments that my knives are always centered. But this wasn’t always the case, after 20 years of research and process control, I’ve been able to bring blades to center with some solid techniques. When looking at your knife in the closed position, the blade and frame need to be parallel. (Parallelism of the blade and frames from the lock relief cut to the end of the handle.)

You’re going to be fighting a couple things when it comes to centering. One is how well did you machine the parts? The second, is how straight is your blade? If you have machined the parts correctly, you can have the blade be out of center because the bevels may have been ground asymmetrical or the heat treat process could have slightly warped the blade. Also, Vise versa, if you ground the blade symmetrical and the pivot hole is not perpendicular to the flats, or the bearing pockets aren’t perpendicular to the flats you’ll run into problems.

Clear as mud? Let’s Review…

When the knife is in the closed position the blade should look parallel with the frame slabs.

Ref Fig 1.

There are a few ways to look for centering.

  • Straight down the knife while closed and the blade and frame sides are parallel. Looking at the gap between the blade sides and the insides of the frame slabs
  • Straight down the knife while closed and the blade and frame sides are parallel. Looking at the gap between the blade tip and the insides of the frame slabs


Figure 1

Not Centered 

Figure 2


Why is Centering Important?

Centering can cause all sorts of issues but mainly it’s a show of craftsmanship. If the centering issue is severe, the blade will rub one of the scales and cause wear and tear that shouldn’t happen. Mostly, it’s an issue that people find to be distasteful in a quality made folding knife.

  • Aesthetics
  • Function
  • Quality

Ref Fig 2

Quick Tips for Centering a Folding Knife

    • Disassemble the knife, clean, and reassemble. When reassembling, start with tightening the pivot, then tighten all the other screws.
    • Check to make sure your blade and frames are flat.
    • Verify your blade and frame holes are perpendicular to the flats.
    • Check that your counterbores are perpendicular to the flats and that they are of the proper depth.
    • Be sure the bevel grinds are symmetrical.
    • Last but not least, make sure the edge bevel grinds are symmetrical.

Best Practices for Successful Centering

    • Always do your assembly in a specific order in a clean environment.
    • Machine your parts with sharp tooling.
    • Invest in good metrology equipment for measuring depth/flatness/perpendicularity.
    • Use rigid machining fixturing that is easy to use.
    • Use quality machining equipment.
    • Make sure that your mill/drill press is in tram (Spindle is perpendicular to the table)

One of the best things that I’ve found to make sure that my blades center on the first try, is to make sure that my mill is perfectly in tram. Using a dial test indicator that mounts in the spindle of your mill, you can easily get everything trammed and you will have a much easier time with the whole process.

I also find that being very clean while machining the parts helps as well. As an example, if you consider that a small chip lodged under a frame can cause your frames to be WAY out of perpendicularity with your spindle (upwards of .020-.030”).


Tools for centering


Centering doesn’t need to be the bane of your existence. It can be a simple thing that if mastered and will bring your knife brand to the highest levels of mastery.



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