Clip Grinding Attachment
The work plate on the clip grinding attachment is 4 X 20 X Ό steel. The brackets
are made from 3 X 3 X Ό angle iron. The arm to attach it to
the KMG is 1 ½ X ½ X 10.
A 3/8 slot is milled in the arm that attaches the fixture to
the KMG. The fixture doesnt need a long range of motion, so
you only need to make two shorter slots centered over the
attaching bolt holes.
The angle iron brackets were clamped together and two holes were
drilled of the size required for tapping 3/8 X 16 thread holes.
The two holes in the bracket for the work plate were drilled out
to 3/8, and the holes in the bracket for the attachment arm
were tapped with 3/8 X 16 threads. The attachment arm
bracket was clamped in the vice on the milling machine and the
bracket was bolted to it through the pivot bolt hole. The bolt
between the two parts was left loose enough so the work plate
bracket could move. A 3/8 end mill was lowered into
the other hole in the work plate bracket, the mill turned on and a Crescent
wrench was used to crank the bracket into the end mill and cut
the curved slot for the adjustment bolt.
Bolt the attachment arm to the KMG. Assemble the brackets
and the work plate and hold them in place with C-clamps.
After squaring everything up, tack weld the parts together.
Take it off of the KMG and weld it together solidly. DO
NOT overdo the welds!!! This fixture does not take a lot
of pressure in use, so it doesnt need huge welds. The
long piece of steel that the work plate is made from will probably warp when you weld it. The
more you weld, the more it warps and it will have to be
Once the attachment
is welded together, the
unit will need to be fitted to your machine by installing it in
front of your flat platen and marking it to saw and grind a
section out to fit around the flat platen. Install the
attachment to your grinder and make marks on the work plate, about an eighth of an
inch outside both edges of your flat platen; laying out vertical
lines about 2 1/4" apart.
Draw a horizontal
line between the two vertical lines, and about 3/4" below the
top of the work plate. Saw out this rectangle area.
attachment on the grinder and set the angle of the work plate to
about 10 degrees.
mounting bolts slightly, so you can slide the attachment. Start
the grinder and push the attachment into the running belt to
grind the back side of the work plate. This will relieve the
back of the plate so that when you use the attachment, the face
of the belt will be close to the front surface of the plate. Grind into the back of the plate until there is about an
1/16" lip left at the front.
Use a file to
clean out the corners of the relieved
I have put
painter's tape over the work plate on my attachment to protect
the blade from scratching. Other materials could be used; and
may work better too. I've heard that it was possible to have
things ceramic coated. Ceramic coating is very hard and slick.
This may be a good option.
The sharp corners
at the back of the riccasso tend to dig into the painters tape
on the work plate. I have found that it helps to also put tape
on the back of the blade.
attachment to the grinder and set the angle that you wish to use
for grinding the blade clip. 20 degrees is often a good angle
to use for bowie knives.
To use the
attachment, hold the knife blade down against the surface of the
work plate at the riccasso. Raise the front of the blade up
into contact with the grinding belt.
To cut radiused plunge cuts in the clip, I made a secondary
platen with the edges rounded to go over the flat platen on the
KMG. (If you like for your clips to have a square shoulder
where they end at the spine, you dont need to use a second
platen). I made the secondary platen out of micarta and used a
3/8 radius round over router to cut the radius on the edges.
It is held in place on the KMG flat platen by two 1/8 pins.
The secondary platen would be better if made from steel. The
micarta wears quickly from the belt going over it. I usually
cut the clip in using only the flat platen on the KMG and then
install the secondary platen just to cut in the radiused
plunges. I recommend making the secondary platen out of steel,
radius the edges as you wish and then heat-treat it.