Saturday, May 2, 2015

Knife tuning...

Case Polishing cloth, DMT Diamond Sharpener, Strop, Denny
knife, and DMT diamond sharpening card.
As with most Caricature carvers my primary woodcarving tool is a knife and as I have said on many occasions it should be a 'proper' caricature carving knife that enables its user to create the best carving possible.  You probably have also heard me state that if I had to have a single knife it would be the former Denny (now OCC Tools) 1 7/8" Straight knife.  It is an excellent all around knife and it usually can be purchased for < $25.
To be clear...for Caricature carving I do not recommend in any shape or form razor blade cutters as they are not reliable and their use often leads to choppy carvings and increased risk of injury.
I also do not recommend bench knives for this style only because of the thickness of their blades.  These type of knives are not by any means deficient, they are just not proper for this style of carving.
Now I do understand that not everyone has an extensive carving budget, but we do not have to be extravagant in our purchases to maintain a knife.  At a minimum a carver should have a strop, strop compound (I use aluminum oxide), and a sharpener of their choosing.
  To be fair I do own an Ultimate Sharpener which is kept close to my carving area for quick touch-ups and a Burke Sharpener for more serious gouge sharpening.  For knives though I do recommend you avoid these as much as possible and take the time to strop and sharpen by hand.  The reason...its our bread and butter and extra time and care should be taken.
  Now I am not an expert sharpener by any means, however I do get the desired result...a "slick" knife.  What that means is that my knife is not only extremely sharp it is also polished.  Now I know there is a debate on whether the inside channels of gouges or the sides of knives should be polished but I would say definitely yes to this as it reduces the drag when making a cut.  Allowing the user greater precision with less fatigue and frustration.
  How do achieve the polish...simple...after stropping the cutting edge...strop the sides of the blade...over time you will be rewarded with a mirror finish and beautiful cuts (better than sandpaper).
  One shape consideration...I was lucky to hear Marv Kaisersatt speak on woodcarving about 10 years ago and he showed us his preferred knife profile.  Of note was his rounding of the knifes spine.  He felt this allowed him greater ability to make curling cuts.  I too round the spine of my knifes as not only does it allow for curling cuts but also eliminates knife drag and wood breaks (i.e.unclean cuts).  I would note that the rounding of the spine changes the knifes rigidity make the blade more flexible which also can mean it more subject to knife tip snapping.
  Take some time to examine your knives and their shapes.  In the case of the pictured knife it had started to develop a tip-up at the tip of the knife and also an negative arc at the center of the cutting surface (interpret this as my knifes cutting edge was not straight).  These developments had come from years of use and stropping (some on the Ultimate Sharpener strop).  As such I needed to bring the knife back into "tune". 
  Tuning a knife depending on the situation takes time and patience and should not be rushed.  Trust me the effort and result are well worth it.  The first step I take when tuning a knife is to reshape the blade bringing the spine and cutting edge to the desired shape, once I have that it is a matter of sharpening the blade.   The length of the sharpening process will depend on the extent of the modifications required to reshape the blade and its condition when starting this process.  The key is to know what you desire and then put forth the effort to achieve this.
  If you are new to sharpening I would recommend getting/borrowing a copy of the video  "Sharpening Simplified" by Everett Ellenwood.  It is a good place to start.  Also if you have a limit I would look into DMTs Diamond Sharpening Cards (about $10 each, 3 different grit levels) which can be found at Woodcraft and other stores.
  Spring is here and I've given you something to contemplate...why not strop up your tools while your at it??

No comments:

Post a Comment