Sunday, March 17, 2013

My Grinding Gear (Part 2)

Currently I use the KMG  primarily with the pictured attachment; in the picture configured for slack belt grinding.  The belt runs across the two rollers without any backing.  This set-up allows for blending the contours of the handle after rough shaping.

With the hardened O1 platen attached I use it for tapering tangs.  The platen that comes with this two wheel attachment is mild steel. After profiling or doing any grinding with it it quickly develops a depression which means flat grinds or tapered tans that are not flat.  So I purchased some O1 and made two fully hardened platens.  They still wear but I am fortunate enough to have a surface grinder with which I can quickly bring them back to flat.

Or with a 36" radius platen attached for full height hollow grinds on some of my beefier knife designs.  This Radius platen is made by knife maker Nathan Carothers in small batches and offered for sale every so often.  The initial thought behind these was duplicating the large stone grinding wheels of days gone by.

Next up is my GIB (Grinder In a Box). Because of its taller profile I use it primarily with the wheels for hollow grinding (it's easier on the neck and back).  It is here pictured with a 10" wheel.
A 6" and 3" wheel; I could not do what I do without these three sizes.
Of course I can't leave well enough alone so I also added a gas compression spring to this grinder also.  This is easily done by abandoning the standard tracking arm pivot hole.  I enlarged the hole provided for the tension spring and used this as my pivot.  The tracking arm is effectively longer and provides room for mounting the cylinder .
I also milled a slot in one of the two holes designated for the tracking arm bracket.  This allows the assembly to be pivoted about 1/8-1/4" for aligning the tracking wheel with the drive wheel.

To be continued...

Sunday, March 3, 2013

My Grinding Gear (Part I)

So I was told by my grandson (Titus) that I need to update my blog.  I appreciate all the people that read about my stuff but his comment kicked me into gear.

All the knife forums I frequent have often and repeated questions about what grinders are used and which is better.  I thought I would show what I use and why.

My KMG (Beaumont Metal Works) as delivered (4/10) and first installed; for those familiar with this grinder  it is belt driven.  The motor normally sits on the bench to the left of the grinder in front of the pulleys.  I did not want to lose this space so I mounted the motor under the bench on a swing plate with the belt running through the bench top.
Almost 3 yrs later and the bench is much dirtier and more crowded
If you want to make knives good lighting is a must. I have tried many set-ups including direct task lighting (too many shadows because your head is directly above your work so task lighting is to one side or the other).  The above unit seems to work best for me.  A 4 bulb fluorescent (daylight bulbs) light fixture hanging at about 6.5' (I'm 6'1")
My heavily used KMG no longer in the factory delivered condition.  It is now used primarily for  the  platen attachment and the small wheel attachement.
The KMG was modified for a number of reasons (shortcomings in my estimation).  As you can see in the above picture it has an added tool slot that came with the MAP arm attachment.  This is not in the recommended location but has been lowered to allow more fexibilty of tooling. 

A closer look shows that the factory handle has been extended and the tensioning spring has been replaced with a gas spring.  The gas spring was the brain child of Brian Fellhoelter.  To be blunt an owner of a KMG is not the sharpest tool in the shed if they don't make this modification.  The tracking is greatly improved and the harmonic/vibration experienced because of imperfect belts, rotation, and the factory compression spring is minimized if not eliminated. 
If you compare this picture to the first you will notice the motor is now mounted on the bench behind the grinder.
I removed the original KMG pulleys, bearing blocks, and shaft and  TIG welded in a plate configured for  56C motor.   I know have the only direct drive KMG I have ever seen.  This modification fixes the absurd drive arrangement of the factory KMG.  The factory drive arrangement takes up space, seems to rob significant power, and adds to the vibration I mentioned above. 
To be continued...