Abstract: In this paper,the machining properties (including planning,sanding,boring,shaping,mortising,turning and crosscutting) of two plantation-grown hardwoods (Betula alnoides and Castanopsis hystrix),compared with commercially common used Quercus mongolia domestically,were investigated. Tests on their planning,sanding,boring,shaping,mortising,turning and cross cutting are conducted according to the criteria ASTM D1666-87 and the test on crosscutting is referred to the method established by New Zealand Forest Research Institute. On the basis of a series of experimental results,various machining characteristics are classified. In the meantime,the individual properties are assigned to the corresponding grades according to different criterion. The results show as follows: 1) All the indexes of B. alnoides and Q. mongolia are in excellent grade except turning property,which is in good and middle grade,respectively. For C. hystrix,five of the properties such as planning,sanding,boring,shaping and crosscutting are in excellent grade,while turning and mortising property are in good grade. 2) The comprehensive quality grade value of the three species,namely,B. alnoides,C. hystrix and Q. mongolia,are 4.35,4.07 and 4.23,respectively,which indicate that the overall quality of machining properties are within the range of excellent grade. 3) From the results of shaping experiment,it can be concluded that,it is appropriate for B. alnoides to be clockwise shaped in parallel region,and counter-clockwise shaped in cross region and end surface,also for C. hystrix to be clockwise shaped in cross region,and counter-clockwise shaped in parallel region and end surface. For Q. mongolia,it is better to be clockwise shaped in all the three regions. 4) For the species of B. alnoides and C. hystrix,the profile arithmetic average deviation,in symbol of Ra,is smaller after sanded by 80 to 120 grit sand paper than that sanded by 120 grit sand paper twice,and the fluctuating range of the former is also smaller. However,for Q. mongolia,the opposite trend was observed. In the meantime,the surface quality of Q. mongolia after planning treatment (rotating velocity of planning blades at 5 000 r·min^-1 ,the amount of cutting marks per inch of 40 and machining thickness of 0.8 mm) is superior to that sanded by 80 to 120 grit sand paper.

Key words: Betula alnoides, Castanopsis hystrix, Quercus mongolica, machining property, quality grade value, quality grade