Paavo Aro. (1942). Eräitä halkosahoilla suoritettujen sahauskokeiden tuloksia. Acta Forestalia Fennica vol. 50 no. 21 article id 7374. https://doi.org/10.14214/aff.7374

English title: Results of sawing experiments using wooden bow saw.

Original keywords: aikatutkimus; katkonta; sahanterät; halkosaha

English keywords: time study; cross-cutting; saw blades; wooden bow saw; bow saw

Abstract | View details | Full text in PDF | Author Info

Effectiveness of 18 different saw blades of wooden bow saw from four producers (Oy Suomen Sandvik Sahat, Epilä Oy, Ab Orsa Sågbladsfabrik Oy, Kone ja Terä Oy) was tested in 1937. The experiments were divided into test series according to type of maintenance of the blade and tree species (Scots pine, Norway spruce and birch) to be sawn. Each saw blade was sharpened into four different sharpening angles (54°, 60°, 64°, 70°). Four blades had markedly longer sawing times compared to the others. These blades had a special serration. In addition, two blades with sparse serration had slightly poorer results than the blades in general. When the tree species were compared, birch (Betula sp.) was slowest to saw followed by Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.).

The PDF includes a summary in German.

Aro, E-mail: pa@mm.unknown

Category : Research article

article id 388, category Research article

Jacob Edlund, Mats Warensjö. (2005). Repeatability in automatic sorting of curved Norway spruce saw logs. Silva Fennica vol. 39 no. 2 article id 388. https://doi.org/10.14214/sf.388

Keywords: Picea abies; compression wood; stem form; bow; scanner; sorting

Abstract | View details | Full text in PDF | Author Info

Sawn wood from curved logs is prone to have cross grain and contain compression wood, both of which affect the dimensional stability. Different types of curvature can, however, have different effects on both the sawing process and board quality, which is why a standard measure of bow height alone is not enough to sort logs or set the log quality. The aim of this study was to evaluate the repeatability when sorting curved saw logs using a 3D log scanner. In the study, 56 logs were categorized into five different curvature types and four different degrees of curvature severity. The logs were run through a Rema 3D log scanner four times, and the external geometry was recorded. From the geometry data, variables describing log shapes were calculated and used to develop models using linear discriminant analysis, which was used to classify the logs according to curvature type. The accuracy and repeatability were evaluated for the classifications with Cohen’s simple Kappa coefficient. The results of this study showed that it is possible to sort logs by curve type using a 3D log scanner, although sorting by curve type was largely dependent on curve severity. The repeatability test determined that the chance of a curved log being graded identically two consecutive times was 0.40, measured as kappa.

Edlund, SLU, Department of Forest Products and Markets, P.O. Box 7060, SE-750 07 Uppsala, Sweden E-mail: jacob.edlund@spm.slu.se
Warensjö, SLU, Department of Forest Products and Markets, P.O. Box 7060, SE-750 07 Uppsala, Sweden E-mail: mw@nn.se

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