How to make a KMG better (GIB content also)

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by David Sharp, Apr 26, 2012.

  1. David Sharp

    David Sharp

    May 23, 2008
    I have had my KMG for 2 yrs; made approx. 60 knives with it.

    The original was a 2hp 220V with the step pulley set-up. Since the first day of grinding I was never able to use the high speed setting and medium would bog under any pressure. I also noticed a few other things when compared to other grinders; it seems that the compression spring (for tensioning the belt) and the drive system (pulleys and belt) induced a harmonic/vibration into the grinder and bench.

    Well two weeks ago everything came to a head. On Saturday the grinder worked and Sunday it did not. This resulted in a week of coordinating parts and delivery so that I could get things up and running on Friday evening.

    This is what I came up with; a pleasure to use and all my issues are gone. A gas tensioned, direct drive KMG and a completed GIB. Of course the gas tensioning idea came from Brian Fellhoelter.


    Being a vehicle nut also I can only compare the gas spring to riding in a car with hydraulic shocks and then one with gas charged shocks; a night and day difference!

    A new VFD rated 2hp motor motor set-up for direct drive on the KMG (almost looks like it should be there!)

    My secret weapon is my wife! I guess she actually listens to my ranting and raving. For our 20th she bought me a GIB kit with and extra upright. I cut out the motor mounting section and TIG welded it in place of the shaft and bearings on the KMG.

    As stated above all of my issues are gone; it tracks better, no vibrations, and I can lean all 6'1" and 235lbs of me into it and it does not slow down (I don't grind like that but it's nice to know it can be done).

    Now the finished GIB:

    Gas sprung also; the spring, eyes and brackets are about $15.00 (too cheap not to do).

    I can't remember where I read about this mod. but I also moved the tensioning arm forward instead of using the pre-cut pivot hole.

    And finally my tracking modification:
    I noticed in assembling the GIB some warpage (to be expected when laser cutting .5" steel), I was concerned about his causing a tracking issue. As you can see I milled a slot into one of the pre-cut mounting holes. I also removed about 1/16" from the left shoulder of the tracking arm mounting bracket. This modification allows the whole assembly to be pivoted slightly to account for non-straight holes or warpage problems.

    Thanks for looking and thanks everybody for all the grinder threads!!!
  2. tedinatl


    Nov 1, 2010
    That's very cool, David. Care to share some specs on the gas lift you used for the GIB?
  3. David Sharp

    David Sharp

    May 23, 2008
    I'll do better than that, here are the McMaster-Carr part #s.

    1-20lb Spring- 9416K111
    2-Eyelet- 9416K84
    DavidHoback likes this.
  4. tedinatl


    Nov 1, 2010
    Awesome, thanks David!
  5. machinistbutler


    Dec 1, 2010
    They both look great. I used a gas shock on my kmg style that I just completed, seems to work perfect and was very easy to mount!
  6. jonnymac44


    Sep 27, 2007
    Nice work David!:thumbup:
  7. Brian.Evans

    Brian.Evans Registered Member

    Aug 20, 2011
    Awesome David!! Thanks for listing the part numbers. I think I'm going to do that with my GIB build.

    I can't see your gib pictures though. Can everyone else see them?
  8. jll346

    jll346 Knife maker Knifemaker / Craftsman / Service Provider

    May 29, 2006
    Excellent work.
  9. Mike Davis

    Mike Davis

    Feb 7, 2006
    Very cool!!! I see that as a must do mod.
  10. NickWheeler


    Dec 3, 1999
    Very nice David!!! :cool: :thumbup: :)
  11. javand


    Oct 17, 2010
    You either got it from Ed Caffrey or me. It looks great! Hopefully the other guys here doing builds currently will see how nice yours is and skip the months of fiddling and just build like yours from the start.

    Great work!
  12. David Sharp

    David Sharp

    May 23, 2008
    Whether you or Ed; Thanks!
    The extra leverage eliminates the need for a handle and gives the extra room to mount the gas spring.

    Thanks for looking and commenting everybody. I was really concerned about the GIB kit making a quality grinder. I have studied all the build threads and watched all the You Tube videos and it seems that it is as good as the effort you put into it. I have a friend down the road that has a Hardcore and this GIB is as quiet or quieter than my KMG or his Hardcore, tracks just as smoothly and has plenty of power.

    I need to plug the gas spring again it seems to have a huge impact on tracking over a tension or compression spring. The tracking on my KMG is more consistent and needs less fine tuning than previously.
  13. Brian.Evans

    Brian.Evans Registered Member

    Aug 20, 2011
    Did you have to use the modification to the tracking wheel bracket, or did everything line up anyway?
  14. TXscout


    Jul 9, 2008
    Excellent idea!!

    how did you come up with the need for that particular "20lb spring", with that specific length to use on the GIB mod??

  15. wolffbite


    May 7, 2010
    Love this! I was just last night toying around with my finances this summer to fund a grinder build. I'm torn between doing a KMG clone and GIB. I'll definitely look at this thread again when the time comes to work on my tensioning and tracking :thumbup:
  16. David Sharp

    David Sharp

    May 23, 2008
    I was very particular when drilling/tapping/aligning. I have not had to use the adjustable tracking wheel bracket. Showed the idea so that those that may issues can have an easy fix if needed. Plus I did not want to take everything apart to correct an issue.

    I think all told the completed GIB was around $850 (grinder, motor, VFD, misc. H/W), I had all the tooling from the KMG. Time is money! A KMG clone will be more labor intensive.
  17. David Sharp

    David Sharp

    May 23, 2008
    Brian Fellhoelter did the brain work on this one. I just referenced pictures he has posted of his custom grinders to figure mounting locations.
  18. javand


    Oct 17, 2010
    You're better off to buy a bare bones kmg and add all the wheels and etc. if you're concerned about assembly. Otherwise, the gib is the best option. If youre competent enough to build a grinder from scratch, I don't see why you wouldn't create a personal design. There are a thousand different ways to build these machines.

    I really recommend for a first grinder buying a kit (gib) or atleast a semi assembled grinder like the kmg. You'll save yourself a lot of heartache, unless you're already a competant machinist like some.
  19. Matthew Gregory

    Matthew Gregory Chief Executive in charge of Entertainment

    Jan 12, 2005
    Pure awesomeness, David!
  20. R. Scheppmann Knives

    R. Scheppmann Knives

    Jul 19, 2011
    For those who don't know yet, David is a perfectionist. The quality of this grinder build resulted in a solid machine that hauls a$$ and is quieter than my Hardcore. I keep trying to rationalize a second grinder when I see his GIB :D

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