Roselli Nikkarinpuukko UHC

Discussion in 'Reviews' started by Frederick89, Nov 25, 2018.

  1. Frederick89

    Frederick89 Scout

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    Third review of the series.


    Roselli Nikkarinpuukko UHC

    I’ve already told Roselli’s history.
    https://bushcraftusa.com/forum/threads/roselli-nikkarinpuukko.236893/
    Now I’ll say of the origin of UHC steel.
    In 1985 Roselli read a study of the Stanford University, analyzing samples of wootz steel apparently produced in Persia during the I century B.C.

    Wootz steel, firstly created in souther India, is considered the ancestor of modern damascus steels and, during the course of history, got itself attributed legendary quality of resilience and flexibility, true or presumed.
    It’s speculated that this kind of crucible steel had been used to forge, among others, the Ulfberth swords. Franks of origin, they were subsequently produced and even falsified by a number of craftsmen from the IX to XII century and some of them were traded or sold in Sweden and Norway.
    Moreover exist some surreal crusades chronicles mentioning Saracen scimitars so flexible that could be used as belts as well as weapons.

    Roselli decided to reproduce it, so started experimenting and producing knives with the first incarnations of the new UHC steel. Since 2000, in collaboration with the Karhula steelworks factory, is produced the current incarnation of UHC, an unalloyed steel with 1,8% C. Roselli doesn’t hesitate to self-define it superior to its historical ancestors and to remark how modern wester technologies can easily improve an eastern product.

    The knife I test here was purchased in 2013 and was temporary loaned to me by a friend.


    blade
    length - 86 mm
    wideness -20 mm
    thickness - 3 mm
    steel - UHC
    grind - flat
    edge angle - 19°, slightly convex
    edge hardness - ~ 65 HRC

    handle
    length - 115 mm
    wideness - 27 mm max.
    thickness - 19 mm max.

    weight
    knife - 70 g
    with sheath - 110 g


    The blade was stamped by a bar of UHC steel, after it was stretched by rollers. The blade is then press forged, grinded and sanded to its final shape. It has an untapered flat section. The heat treatment is done to batches of twenty five blades at a time, quenched in salt water and tempered in oven. The bevels are grinded to 19° with just a bit of convex to the edge.

    The common birch handle is roughed out on routers and finished on belt sander with a medium grit. It has a 3 mm nickel silver bolster, medium proportions and tapers strongly towards the blade, both in thickness and wideness. It has a hint of hooked pommel and a reverse teardrop section.

    The sheath, made of 2 mm leather, is machine stitched. The leather of the mouth is folded inside to increase the retention; there is a double sided plastic liner; the belt loop has two simple slots. The retention isn’t strong anymore and the knife comes out easily.

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    To be continued.
     
    Last edited: Nov 25, 2018
  2. Frederick89

    Frederick89 Scout

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    In use

    When I first got it the edge was a bit rough and had a few microchips. I resharpened it with DMT #600 and #1200, then stropped with Bark River black (#3000) and green (#6000) compound. It took me about fifteen minutes, of which ten of stropping alone, to get the edge perfectly smooth and shaving sharp. It didn’t feel particularly difficult to me, the steel was clearly hard, but was giving in quite easily to the actual abrasion from the stones and compound. It took me about the same time as the 52100 at 62 HRC I have on three other puukkos, which are grinded at 21° though.

    Let’s start with the usual six months seasoned plane spikkentrolls.
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    The puukko had good bite, though the convex edge was not that incisive working against the grain and perpendicular to it. At the end of the first troll the bite was unchanged, but the edge felt somewhat “unclean”. While doing finishing cuts on the second troll the loss of bite became perceivable and, once I was cutting off some curls, I had to apply more force than expected ended up decapitating the hat. I settle down by rounding its top, then.
    At the end of the work, having planed down two knots too, the edge was unclean, without rolls or chips and the bite gone. I got it back shaving with six passes per side of black compound and twenty five of green.
    [​IMG]

    I continued with the three months seasoned poplar wood wizard.
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    The bite was good, working both down grain and against it, though not extremely incisive due to the convexing. The tip, just a hair finer than the W75 version, was a little more nimble engraving the sides of the nos, but was still too thick to work well the lip. I felt the strongest resistance while cutting the notches around the branch, to separate the wizard from it. At the same time felt clearly the bite loss.
    At the end of the work the edge was pristine, the bite gone. I take it back with twenty passes on black compound and forty on green.
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    I concluded with the one year seasoned silver fir spatula.
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    As already seen with the W75 version, the convex edges has a tendency to slip when planing the sides and isn’t particularly aggressive. There was a clear resistance while carving tangentially, to rough out the very front of the spatula. The spine felt a bit too sharp a couple of times, while pushing for planing cuts and during all the process I felt a light but constant loss of bite, not enough though to strop it half way through the work.
    At the end of the roughing the shaving bite was gone, but maintained sufficient aggressiveness not to induce me to apply much more force. All the finishing cuts were quite fast and easy and again not enough bite loss to induce stropping.
    At the end the edge felt unclean and, as said, the bite was gone. I took it back with twenty passes of black compound and fifty on green.
    [​IMG]


    Conclusions

    I already commented on how this handle is probably the most comfortable among factory made puukkos.
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    Roselli claims that UHC steel has double the edge holding of normal carbon steel. True, but only if the comparison is done with the W75 of the standard models.
    Even though longer to sharpen and touch up than W75, UHC is nothing mystical or intractable. The only, predictable, difference is that W75 can be easily sharpened with natural whetstones, while UHC requires diamond stones.
    So surely UHC is a good step forward in edge holding compared to W75 and will be able to stand more work on dry wood or longer period without touching up.
    Even though is undeniable that UHC doesn’t hold up too well compared to simple alloyed carbon steels like C75 or 1085. Both have some small amount of Manganese to form carbides and it shows. Both gain in edge holding coming close to UHC in this matter, especially 1085, while remaining way faster to touch up.
    [​IMG]
     
    Last edited: Nov 25, 2018
  3. KFF

    KFF Scout

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    Just a question, convex grind? Not scandi? Factory convex?
     
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  4. Frederick89

    Frederick89 Scout

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    The bevels are flat "scandi", the very edge is convexed.
     
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