HowToMirrorMate - Van Dyk Knives by sdsdfqw21


									                           Van Dyk Knives

                           Van Dyk Knives
•   The ‘Mirror Mate’ polishing machine was born out of many years of struggle and
    experimenting with the various methods and ways to achieve an acceptable mirror
    finish on the flats and hollows of a knife blade.
•   There were many inputs gained from talks at knife meetings, articles and tutorials
    on the internet (Thanks Rob Brown) and also personal preferences of how I like to
    do things.
•   It is a very easy and uncomplicated machine and if used within the operating
    parameters described below, you will obtain a high level of finish as well as a very
    practical way to flatten blades, tangs and folder liners.
•   The main feature of the machine is that all flat grinding is done with the disk
    spinning horizontally, which is a much more natural way to stand and grind.
•   The horizontal wheel is 230mm in diameter (The size of the narrowest part of
    your water paper) and has a 0,76mm layer of sheet magnet glued to it.
•   In the center of the wheel a 6,0mm locating Allen screw is positioned to act as a
    locating pin for a 6,0mm plate glass that has sheet magnet glued to it’s bottom and
    it also secures the wheels to the motor shaft.
•   When the glass which has a 10,0mm hole in the center of it, for locating purposes,
    is placed on the disk and after the glass is slid to the left or right the magnets will
    lock and a secure perfectly flat surface is in position for you to glue your water
    paper on.
•   Beneath the horizontally mounted wheel a 300mm diameter rubberized wheel is
    fitted, which can be used for finishing in the hollow of your blade, once the
    machine is tilted 90° with the wheels in the vertical position. Various grits of water
    paper can now be glued to it’s surface with 3M spray 75 glue.
•   The wheels are manufactured from 32mm thick ‘Supa’ wood and the 300mm wheel
    has a 6,0mm thick special rubber for the application of your contact glue spray.
•   The rubber has the right compression density and is chemical resistant.
•   One would think, why not make use of aluminum wheels and disks? But when
    considering the application of this machine, it would not justify the cost.
•   Firstly the speed required for polishing is less than 50% of the motor’s rated speed
    and secondly there is very little force applied to the wheel and disk, as polishing is
    done with a very ‘light’ touch.
•   The unit is designed as a table top mounted machine. It requires very little space
    and can be secured either via three 10mm bolts (Holes pre-drilled) or simply by
    making use of a suitable G-clamp.
•   A well known motor type (Leroy Somer) is used, of which I have used on all my
    machines in my workshop over the last six years with excellent results.
•   Below are the principles and parameters that are to be used with this machine.

                            Van Dyk Knives

MOTOR: 0,75kw - three phase four pole motor – 1400rpm.
Variable Speed Drive: Can be used with a 0.75kw or larger. (230V - 1ph in 230V -
3ph out - E.g. Digidrive)
Foot switch: The use of a foot switch with your variable speed drive is a plus, but
not essential.
Motor Direction: The forward/reverse direction change facility of your variable
speed drive is ideal, as the life of your water paper will be extended. (I use my water
paper dry)
Motor Speed: Polishing only requires a speed of ±500 rpm (±15 – 20 Hz).
Therefore, the disk should operate at a speed of ±15 (±420 rpm) and 20Hz (±560
rpm). (Do not go above 20Hz (±560 rpm) as this might cause the disk to loose
magnetic attraction due the centrifugal forces.)
Glue: The best glue for the purpose of sticking your water paper down, especially on
the rubberized 300mm wheel is the 3M spray 75, as it can be re-used with several
applications of the water paper. On the glass I use the normal Gemken contact
adhesive spray which does not stick as well as the 3M spray 75, but, because a
downward pressure is being applied the paper tends to stay stuck and easy to clean
between applications.


  A. Polishing the hollow – Machine with 300mm wheel in the vertical position
  (Remember to remove the glass disk before you tilt the machine)
• As with everything in the business of knife making, there are many ways of
  achieving results. But, I have enough confidence that knife makers in general have
  enough savvy, intelligence and experience to experiment with processes,
  equipment and procedures to obtain the best results they can.
• Below is the process I use and hope that it will be of help to all who use this
• I need to say, that early in my knife making journey I have made use of the Rob
  Brown method of doing things as found in his tutorials on the internet. So many of
  my ideas stem from his methods.
  1. After heat treatment, prepare your blade to the point where you are ready to
      start your mirror polishing on the hollow grind. I normally use my various
      grades of belts to profile, clean and polish the hollow and then hand rub the
      hollow to a 400 grit finish – no scratches must be visible.
  2. The ricasso area and flat sides of the blade can be sanded to a 220 grit finish.
      We will go back to do the final polishing after the hollow has been polished.
      (No scratches must be visible)
  3. Measure the width of your contact wheel and using this dimension transfer it
      along both top and bottom edges of your first sheet of 400 grit paper, use your

                           Van Dyk Knives
      steel rule and a sharp blade to cut it into strips to match the width of the
  4. After spraying the glue on to your wheel (Cover the rest of your machine with
      a cloth to prevent the glue over-spray from contaminating it), you can now
      stick your strips of paper on to the wheel, carefully lined up with the edges and
      butt joined against each other. Press the joints down firmly with your thumbs
      and press down the paper with the heel of your hands. (If you can obtain water
      paper in long strips it would make your job easier)
  5. To make sure that you don’t put scratches onto the blade, the edges of the
      paper must be smoothed by means of a peace of hardened steel of some sorts.
      (Remember your biggest enemy in polishing is particles of dust, grit or any
      other contaminant.)
  6. Before you bring the blade into contact, make sure that the surface of your
      paper is clean.
  7. You are now ready to polish, but remember the idea is not to reshape the
      profile, but to polish the surface. So use a lighter pressure against the paper
      than you normally do on the belt and slow down the movement across the face
      of the wheel. After every few passes don’t forget to cool the blade down and
      clean the paper surface.
  8. I do all the machine sanding dry; your wheel should run at +- 500 rpm (±15 –
      20 Hz). You can also experiment with different speeds. Do not move on to the
      next grade of paper until all the previous grade scratch pattern has been
  9. After the 400 grit session you can move to a 800 grit and then 1200. You may
      want to leave the blade with a horizontal satin finish or go to the next step
  10. If no scratches can be observed you can move to your buff and finish the
      hollow to a high quality mirror finish.

  B. Polishing the ricasso and blade flats – With the wheels tilted to the
  horizontal position
  (Remember to screw in the locking device)
  1. Place one of the glass disks with the relevant grit sized paper on to the disk –
     locate the center hole and twist till the glass is felt to lock.
  2. Set your direction and speed of motor. Speed between 15Hz – 20Hz+- (420
     rpm - +- 560 rpm).
  3. Start the motor via the foot switch and use a piece of hard wood on the edge
     of the sand papered glass to removed any protruding sharp edges, which will
     cut like a knife if left un-addressed. Clean the water paper surface by means of
     compressed air or whichever method suits you.
  4. If the ricasso has been sanded to 220 grit you can go straight to a 400 grit disk.
     Make sure not scratch the perfectly mirrored hollow. (Masking tape is a good

                            Van Dyk Knives
   5. By pressing squarely and lightly on the blade, start the motor by means of the
      foot switch. To check your grinding doesn’t lift the blade till the motor has
      stopped. (Remember to cool the blade and clean the every so often)
   6. Once you are satisfied that all the 220 grit scratch pattern has been removed,
      you can remove the 400 grit glass and place the 800 grit one in place.
      Remember to do step 3 again.
   7. Work your way up to 1200, 1500 or even 2000 grit if you want to, on both
      sides of the blade.
   8. Your blade is now ready for the final buffing phase. Remove the tape if used,
      clean of all grit and marks and buff as lightly as you can. Remember two things.
      Firstly, it is the buffing soap that does the polishing , not the pressure on the
      buff and secondly, after the flattening of the ricasso and flats of the blade there
      will be a crisp clear grind line, don’t buff it away.

   The Mirror Mate consists of the following:
   1. Main Mirror Mate motor unit including, double mounted wheel, hinged motor
      bracket and base plate with horizontal locking screw.
   2. Four 6,0mm plate glass disks with relevant holes and sheet magnet attached.
   3. One set of operating instructions.
   4. Does not include a variable speed drive.

                           Van Dyk Knives

     One year guarantee on motor electrical and mechanical.

     Note! Plate glass not covered under the above. Please remember that
     the glass disk might be slightly out of true when spinning, this is as
     result of the lack of accuracy from the supplier during the cutting and
     grinding of the glass.

Distributed by:

Dries van Dyk Knives, 082 851 6044,

Knife Machines and Tools, 087 808 2400/1, sales


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