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Increasing detent strength on Spyderco Amalgam

Discussion in 'Maintenance, Tinkering & Embellishment' started by shunsui, Dec 17, 2018.

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  1. shunsui

    shunsui Gold Member Gold Member

    Aug 12, 2008
    Love my Spyderco Amalgam, but it shakes open rather easily.
    I ordered a KYOCERA 1635-0625.094 Ball Nose End Mill to modify the detent hole.
    The big river has it.

    First of all BIG thanks to M0DiFiEDZ for his classic video on all this detent mod stuff.

    Also BIG thanks to Nick Shabazz for his video on the Amalagam:
    How to disassemble and maintain the Spyderco Amalgam Pocketknife

    This is the stuff you need to do the job.

    Hand force is all that's needed on the cutter. No need for a drill or dremel tool.
    I used a plain tap & die set collet to hold the KYOCERA 1635-0625.094

    You'll need a T8 torx driver. (I'd get a Wiha if I were you.)
    The BelOMO Triplet 10x is an eye loupe to get a better look at your work.
    The blue and white thing is just a carved up toothbrush handle I use for a pry bar.
    I never even taped up the blade, but you might want to.

    When you take the knife apart, you'll notice the detent hole is drilled all the way through the blade. This is handy because you can practice on the side that's not used for the detent and get a feel for the cutting tool.

    Work slowly, cutting just a bit at a time, and reassemble the knife to test the detent as you go.

    I tested the detent strength with a trigger pull gauge.

    My original detent was between 7-11 oz. You could shake it open with one shake.

    I did three grinds on the detent hole progressively increasing the detent strength:

    15 oz
    1 lb 7 oz
    2 lb 4 oz

    At 2 lbs 4 oz, the visible detent ball was about 80-90% in the hole. I didn't want to take it any further as I wanted the ball supporting the lock bar, rather than the bar flat on the blade.

    Note that what I've done is enlarge the very top of the detent hole with a larger ball shaped cutting tool. The result is a bevel or cup at the top of the hole for the detent ball to nestle down in.
    Keep in mind that everything here is rather small. Doesn't take much cutting to do the job.
    I came close to overshooting where I wanted to be. Go slow.

    This is the result
    jpm2, knaf, bucketstove and 4 others like this.
  2. dsalazar

    dsalazar Gold Member Gold Member

    Jun 22, 2017
    This is
    This is good info. I have adjusted 6 detents to my liking. I actually like getting weak ones to tune them to how I want. I use a diamond bit out of dremel kit but with no power. The bits are a cone shape so they fit in the hole and allow a little removal while keeping cylinder shape.
    shunsui and 4mer_FMF like this.
  3. DaveDM


    Dec 21, 2017
    I used similar dremel bit '2.4 mm diamond coated cutter' by hand to tune a detent ball. It worked very well. I have jack at canadian cutting edge to thank for this video (although he used it powered). Although M0DiFiEDZ video is more technical and detailed.
    Rob Skinner and shunsui like this.
  4. Liquid Cobra

    Liquid Cobra

    Feb 17, 2013
    I just did this mod on my amalgam and sliverax, it worked out really well. Thanks!
    GundaManiac, shunsui and knaf like this.
  5. thecigarguy

    thecigarguy Gold Member Gold Member

    Mar 31, 2018
    I don't own a tap and die set. Can you make a recommendation on this for finding one that fits the kyocera bits?
  6. shunsui

    shunsui Gold Member Gold Member

    Aug 12, 2008
    You should be able to find a tap and die set collet at your local hardware store.
    I think mine was a DeWalt.
    Mine is for 0 - 1/4" shafts. They adjust like the bit holder on an electric drill.

    The shaft on the above Kyocera is 0.125" or 1/8".
    Last edited: May 27, 2019
    thecigarguy likes this.
  7. Wowbagger


    Sep 20, 2015
    These are quite different from the drill chuck.
    Tap handles are designed to hold square ended taps.
    Drill chucks hold round bits and is what you want for the end mill.

    I do a whole lot of this kind of thing and this is what I like the best but it takes some assembly of a few separate parts :
    Klein Tools 32698 Switch Drive Cushion-Grip Handle, Fits 1/4" Shank.
    This has been upgraded to the following model
    Adjustable Length Screwdriver Handle Klein Tools 32619 LINK > > >

    and you may want to try one at a brick and mortar store (electrical supply) before buying

    To this I added
    Neiko 20754A 3/8” Drill Chuck with 1/4” Quick Change Hex Shank LINK > > >

    The advantage is you can clamp the bit MUCH more securely than the inappropriate tap handle.

    PS: I think I would have just bent the liner or frame lock bar over ever so slightly to add more tension to it. I have done this both to add tension and to lessen tension. Worked well so far.
    Last edited: May 27, 2019
    shunsui likes this.
  8. shunsui

    shunsui Gold Member Gold Member

    Aug 12, 2008
    It's not a problem in this application. The amount of force needed is very small. You could probably do the job holding the tool in your fingers. The collet was just easier and the design of the head worked fine with the 1/8" shaft.

    I think the basic information I wanted to share has been covered here, so I'm going to lock the thread. Feel free to start a new thread on the topic.
    Last edited: May 29, 2019
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