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In situ comparison of radial and point-attack bits.

Authors
Sundae-LS; Myren-TA
Source
USBM 1987 Jan; :1-15
Link
NIOSHTIC No.
10005968
Abstract
The Bureau of Mines conducted a series of tests to compare the cutting forces required by radial and point-attack bits when making similar cuts. Three radial and four point-attack bits were tested in two coal mines using the Bureau's in-seam tester to measure coal- cutting forces in situ. Tests were also conducted to investigate the effects of weathering and cleating. The test results show that in each case, at a specific clearance angle, the radial bits required less tangential and much less normal force than the point- attack bits. The resultant of the cutting forces for some types of cut was 50 pct less at mine 1 for radial cuts compared to cuts with the best point-attack bit, and 40 pct less at mine 2. There was some difference between the three types of radial bits tested, but it was not as significant as the difference betwen each type of point-attack bit. Cutting coal perpendicular to the cleat planes required less cutting and normal force than the same type of cuts parallel to the cleat planes. Test results showed no effect due to weathering on cutting force data. Cutting parallel increased forces only because cuts were made in the rock band.
Keywords
Mining-equipment; Mining-industry; Mine-workers; Cutting-tools; Tools; Force; Testing-equipment
Publication Date
19870101
Document Type
IH; Report of Investigations
Fiscal Year
1987
NTIS Accession No.
PB88-229844
NTIS Price
A03
Identifying No.
RI-9127
NIOSH Division
TCRC
Source Name
U.S. Bureau of Mines
State
MN
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