Canadian wood products industries . all Knives into Cutting Circle ThoughThis May be Accomplished by Grinding Knives on Head By A. P. Redden* There is room for considerable improvement inthe knife grinding and jointing methods as followedin many plants. The old laborious and inaccuratemethod of removing the knives from the heads, grind-ing them and then tediously setting them in linewith the bed is rapidly passing into disfavor and isbeing replaced by modern grinding-on-head and joint-ing practices. The angle or bevel on the knife itself is of primeimportance and often makes the difference bet
Canadian wood products industries . all Knives into Cutting Circle ThoughThis May be Accomplished by Grinding Knives on Head By A. P. Redden* There is room for considerable improvement inthe knife grinding and jointing methods as followedin many plants. The old laborious and inaccuratemethod of removing the knives from the heads, grind-ing them and then tediously setting them in linewith the bed is rapidly passing into disfavor and isbeing replaced by modern grinding-on-head and joint-ing practices. The angle or bevel on the knife itself is of primeimportance and often makes the difference betweenpoor and satisfactory work. The accompanyingsketch shows the usual method of measuring theknife angle- X is a perpendicular passing throughthe centre of the cylinder, A is the angle of edge of the knife coincides with the points ofintersection of the perpendicular and the stock. The proper angle of cut depends upon the kindof stock being planed, also the quality and quantityof work required. Softwood and quick work from. Showing how angle of cut is ascertained 38 to 45 degrees- Hardwood and fine work from 80to 85 degrees. This will not rip any cross grainedstock. An angle of 65 to 70 degrees has been foundto give the best universal results. The different an-gles of cut are generally obtained by back grinding,however the manufacturers of cylindrical heads aremaking heads with the knives set at a greater anglethan formerly and back grinding is not necessary. Proper Bevel for Planer Knives The amount of heel clearance used is somethingthat is generally carried to excess. The heel of theknife should have a very small clearance- If knivesare ground with a long bevel, the edges will be thinand weak, very easily nicked and will also chatter inthe cut, and if set with a short overhang are sure tocrack. Many planer men drift into the habit of long bev-els to avoid grinding. Taking off, grinding and re-setting knives requires a lot of time, and if they canwhet and file them a
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectfurnitu, bookyear1922
