A custom paring knife made by Alvin Johnston :
The black is just a marker used to show the primary grind, the knife is sharpened flat to the stone so the marker shows what doesn't make contact with the abrasive.
The paring knife is ground from 1095 high carbon steel hardened to 66 HRC. The blade is 0.055" thick, 0.41" wide, 2.8" long and weighs 35 g. The edge is 0.010-0.012" thick, ground at 5.7 +/- 0.4 degrees. At 0.2" back from the edge the knife is 0.021" thick. There is a full distal taper to point.
According to the maker :
Heat at austenizing temperature for 1 minute for 1095. I watch for the shadow in the unaustenized portion. caused by the arrest point. (I need an oven). Quench in 120øF quenching oil. Cool to -5øF for 1/2 hour. Temper at 212øF (boiling water) for 15 - 30 minutes. Cool to -5øF for 1/2 hour. Draw at 325øF for 1 hour.
The cold treatments + boiling water tempers are to maximize transformation to martensite. The tempering temperature was chosen to meet the peak torsional toughness :
This also gives a very high torsional strength :
The above graph is for a slightly higher carbon steel than 1095.
With the new in box edge the paring knife cut ropes very well being very sharp with a thin and acute geometry. It push cut 3/8" hemp with 14.5 (5) lbs with enough slicing aggression to reduce the force to 12.5 (5) lbs.
The small paring knife is optimally designed for paring, hence the name. The very narrow blade allows turning sharply which enhances peeling ability and the very thin and acute edge drastically lowers the force required to push the knife through vegetables.
It doesn't have the optimal length for more general use, slicing and such, it does fairly well though different methods have to be used. Dicing up onions for example, the knife is held on a 45 and drawn across the onion instead of the normal pinch grip and chopping motion used with utility blades :
It also readily glides through fresh breads, but due to the lack of length, often needs to either make multiple cuts or work around the loaf to make a complete cut :
It can also be used to work on meats readily, on multiple occasions it served to take apart various poultry :
The breasts were cut off, the legs removed and seperated, the wings removed and the tips cut off, and the body cut into pieces with the tailbone removed.
The only downside for kitchen work is that 1095 will rust fairly easily if left wet, especially if exposed to salts or acidic juices, rinse and dry the knife after use.
While not made to do so, the small paring knife can be used for a large variety of bushcraft on all manner of vegetation.
Cutting light grass and soft vegetation isn't very demanding of a knife, a $5 machete can do it all day long and it pretty much the optimal blade to do so. The only real requirement is that the edge be very sharp. The sharper the blade the less of a draw is required.
Grasses and light brush are usually easily just pulled or ripped up by hand, however even a small blade like this one makes the process go much faster and the cleaner cuts keeps the vegetation together which is beneficial for braiding for cordage.
Though the edge of the paring knife is very thin and acute, there is no problem cutting hard wood, it easily makes a pile of shavings out of hardwood birch flooring :
Moving outside it handles fresh wood of various types, including some fairly rugged tasks considering the type of knife such as skinning the bark off an old spruce round for tinder :
This included working with knots, care was taken not to twist the blade while cutting around and through the knots.
It could also be used to cut down alders up to a couple of inches thick readily. The sticks were bent to put them under tension and then sliced with the knife which caused them to crack open, the knife then further open the crack with more slicing. On average it took 10-20 seconds to cut a piece down :
On tougher wood, the same process was used, though it took longer, 20-30 seconds, mainly because it was harder to bend the boughs down due to ingrowth and the wood was inherently a lot harder :
On the first few bough the cutting was done roughly, and the edge distorted a little mainly through contacts with knots and the snaps due to the branch breaking with the knife in the cut. More branches were cut to see how the damage propogated and soon a small chip came out of the edge, just barely visible.
The blade was 0.002" thick behind the chip (yes that is two thousands, not a typo). The method was adjusted slightly then to reduce rocking motions and continued with the tip of the knife which is even more acute to verify that with care the knife can easily handle the work with the edge not requiring a heavier micro-bevel.
The paring knife work very well cutting ropes, cardboard and other materials, it has a very slim profile which gives it high cutting ability and since the blade is very short it has high control :
It is also capable of cutting much harder materials, and there isn't anything that it really won't be used to cut including old dirty carpet :
Which was easily cut into strips :
The knife also has no problems carving up bone for improvising hooks and needles, some work with an old rib bone (pig) :
This can be used to make needles and hooks. During this session there was some side torquing due to sloppy technique near the the tip with more than 1/16" deep slices and the edge rolled a little.
In regards to general utility work in general, there is not much outside the ability of the knife, it easily takes apart and old sneaker :
and doesn't even shy away from work which even gets the "abuse" label for heavy tactical knives - sod grubbing :
Using an icepick grip the knife cut one inch into the sod to make a small rectangle. The front of the sod was then cut at at 45 degree angle so it could be peeled back and then it was basically skinned off.
After the sneaker, bone and sod cutting there was no visble damage to the knife, though it was worn from the dirt. The first inch near the blade could still do clean press cuts on paper, near the tip the cuts were ragged and needed some back and forth slicing.
After the above sod cutting the paring knife was honed with waterstones, starting with a 1000 grit and finishing with a fine chinese natural stone then some light stropping on Cr0, the entire process took just a few minutes. Though the steel is very hard, the knife sharpens easily because the profile minimizes the edge profile and thus there is very little material to remove when sharpening.
The ease of sharpening is enhanced by the ability of the edge to resist damage when cutting due to the high strength and torsional toughness and thus even after challenging tasks very little work needs to be done to restore optimal sharpness. A further benefit to the above described heat treatment is that it provides a very fine grain and an edge which has little tendancy to form a burr.
The paring knife was intended to be ran against other blades however a few initial runs showed the matter was a bit complicated. The first comparison was against a small Sebenza in S30V which had been modified so that the edge was ground so a similar include angle as found on the paring knife. Some trials were made on plastics and the edge on the Sebenza rippled while the edge on the paring knife did not.
The cutting media was then changed to cardboard and a standard run performed, push cuts made through 1/8" ridged carboard, with one cm section of blade used, with the knives on a 45 degree angle to the cardboard. The Sebenza blunted significantly faster using thread cutting to measure the sharpness, but it also blunted in a different manner.
After about ten meters of cardboard were cut, the knives were at about 25% or optimal sharpness, the sharpness of the Sebenza was significantly lower than the 1095 knife about 20%, but more significant was the level of damage and the influence on sharpening. The 1095 blade was lightly steeled and was shaving again, the edge on the Sebenza had torn/chipped and could not be restored on the steel.
The damage on the Sebenza was visible and could also not be restored on a fine stone, a medium grit waterstone was needed to reset the edge. Thus if edge retention was judged by the amount of material which needed to be cut until both blades required significant honing, the 1095 blade would be many to one times better because of the higher edge integrity [a phrase coined by the maker : ref].
The grip is ideal for a small paring knife, comfortable in a variety of grips, not specific to any. As a general use grip it has limitations, mainly low security, but as noted this is a design specific paring knife.
Comments can be emailed to cliffstamp[REMOVE]@cutleryscience.com or by posting in the following thread :
More information on the makers knives can be obtained at
Alvin's Knife Website. He can also
be found on rec.knives.
| Last updated : | |
| Originally written: | 05 : 05 : 2005 |