1、BRITISH STANDARD BS 1919-2: 1995 Hacksaw blades Part 2: Specification for cutting performance UDC 621.932.4.023.001.4BS1919-2:1995 This British Standard, having been prepared under the directionof the Engineering SectorBoard, was published underthe authority of the Standards Board and comesintoeffec
2、t on 15March1995 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference MTE/8 Draft for comment 94/700316 DC ISBN 0 580 23288 3 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Engineering Sector
3、 Board to Technical Committee MTE/8, upon which the following bodies were represented: Association of Engineering Distributors Ltd. British Engineers Cutting Tools Association British Hacksaw and Bandsaw Manufacturers Association Gauge and Tool Makers Association Ministry of Defence Amendments issue
4、d since publication Amd. No. Date CommentsBS1919-2:1995 BSI 10-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 References 1 3 Definitions 1 4 Cutting performance 1 Annex A (normative) Methods for testing the performance of hand and powerhacksaw blades 3 Annex B
5、 (informative) Examples of equipment for testing hacksaw blades 5 Annex C (informative) Example of test sheets 10 Figure B.1 Method of measuring static load (hand blade test) 7 Figure B.2 Method of measuring static load (power blade test) 8 Figure B.3 Test bar clamp 9 Figure C.1 Test record sheet fo
6、r8 cut test 10 Figure C.2 Test record sheet for10 cut test 11 Table 1 Test conditions and acceptance limits for hand blade cutting tests 1 Table 2 Test conditions and acceptance limits for power blade cutting (high speed steel, all hard and bimetal) 2 Table A.1 Static load at top cut for hand blades
7、 4 Table A.2 Static load at top cut for power blades 4 List of references Inside back coverBS1919-2:1995 ii BSI 10-1999 Foreword This Part of BS1919 has been prepared under the direction of the Engineering Sector Board. First published in1953, BS1919 was revised in1967, partly to achieve a rationali
8、zation of sizes but also as a step towards metrication. The standard was further revised in1974 to take into account international agreement within ISO on hacksaw blades and to add the flexible type of high speed hacksaw blade. BS1919 was further revised in1983 to include the important bimetal types
9、 of hacksaw blade and requirements for both power and hand hacksaw blades. The present revision of BS1919 divides the1983 edition into two Parts. This Part of BS1919 has been produced in advance of the related standard ISO2336 that is being prepared by the International Organization for Standardizat
10、ion (ISO). BS1919-1 specifies the dimensions of hand and machine hacksaw blades and also includes the static bend test for hand blades only. This Part of BS1919 together with Part1 supersedes BS1919:1983, which is withdrawn. A British Standard does not purport to include all the necessary provisions
11、 of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to12, an inside
12、back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS1919-2:1995 BSI 10-1999 1 1 Scope This Part of BS1919 specifies the performance requirements and method
13、s of test of hand hacksaw and machine hacksaw blades specified in BS 1919-1. Examples of equipment for testing hacksaw blades are given inAnnex B. 2 Normative references This standard incorporates, by dated or undated reference, provisions from other publications. These normative references are made
14、 at the appropriate places in the text and the cited publications are listed on the inside back cover. For dated references, only the edition cited applies; any subsequent amendments to or revisions of the cited publication apply to this Part of BS1919 only when incorporated in the reference by amen
15、dment or revision. For undated references, the latest edition of the cited publication applies, together with any amendments. 3 Definitions For the purposes of this British Standard the definitions given in BS 1919-1:1993 apply. 4 Cutting performance When tested in accordance withAnnex A, the wear r
16、ate of the hand or machine blade and the total time taken to complete the number of cuts shall not exceed the values given inTable 1 andTable 2 for the type of blade tested. The blade shall not produce a cut more than3mm out of square. The blade shall not break. A new blade shall be used for each te
17、st. Table 1 Test conditions and acceptance limits for hand blade cutting tests Blade type Blade dimensions Speed No. of cuts Test bar Wear rate Total time Thickness Pitch No. of teeth No. of strips Thickness of strip mm mm Strokes/min mm High speed steel: all hard and bimetal 0.63 0.63 0.63 0.63 1.8
18、 1.4 1.0 0.8 14 18 24 32 70 70 70 70 10 10 10 10 10 10 9 8 2.6 0.05 2.6 0.05 2.6 0.05 2.6 0.05 33 37 40 40 92 112 124 132 High speed steel: flexible 0.63 0.63 0.63 0.63 1.8 1.4 1.0 0.8 14 18 24 32 70 70 70 70 8 8 8 8 10 10 9 8 2.6 0.05 2.6 0.05 2.6 0.05 2.6 0.05 73 78 118 120 122 132 146 149 Low all
19、oy steel: flexible 0.63 0.63 0.63 0.63 1.8 1.4 1.0 0.8 14 18 24 32 35 35 35 35 8 8 8 8 5 5 5 4 2.6 0.05 2.6 0.05 2.6 0.05 2.6 0.05 44 40 34 37 134 123 147 127BS1919-2:1995 2 BSI 10-1999 Table 2 Test conditions and acceptance limits for power blade cutting tests (high speed steel, all hard and bimeta
20、l) Blade dimensions Speed No. of cuts Test bar Wear rate Total time Length Width Thickness Pitch No. of strips Thickness of strip mm mm mm mm Strokes/min mm 300 and350 25 1.25 1.8 124 10 15 2.6 0.05 66 66 300 and350 25 1.25 2.5 124 10 20 2.6 0.05 56 61 350 400 450 32 1.60 2.5 124 10 20 2.6 0.05 65 8
21、7 350 400 450 32 1.60 4.0 124 10 25 2.6 0.05 47 60 400 450 40 2.00 4.0 124 10 25 2.6 0.05 81 80 400 450 40 2.00 6.3 124 10 25 2.6 0.05 69 76BS1919-2:1995 BSI 10-1999 3 Annex A(normative) Methods for testing the performance of hand and power hacksaw blades A.1 Principle The cutting performance of han
22、d and power blades is assessed by subjecting sample blades to an accelerated test using calibrated hacksawing machines to control the variables in friction, stroke characteristics and loads. The standard test bar is chosen to induce sufficient wear to the blade and to provide by its homogeneous stru
23、cture reproducible machining characteristics. A.2 Test bar A test bar consisting of lengths of cold rolled18/8 stainless steel strip, type304S15in accordance withTable 2 of BS1449-2:1983, having the following analysis. The strip shall be25.0mm 0.15mm in width,2.6mm 0.05mm in thickness. Thehardness s
24、hall be180 12HV30, and the finish shall be type2B. The material shall have rolled or prepared edges. Ragged sheared edges are to be avoided. A.3 Apparatus A.3.1 Test machine for hand blades A power hacksaw machine as follows: a) in good condition, particularly in respect of stroke alignment and free
25、dom from excessive vibration; b) with main slides sufficiently free from friction to prevent variations in dynamic loads; c) with the main pivot on the same axis as the crank drive shaft; d) which cuts on the forward stroke; e) which presents the blade at an inclination of115 10 relative to the mach
26、ine slides in the direction of cut (seeFigure B.1); f) with a stroke length of153mm1mm; g) with a cutting speed of70 strokes/min2strokes/min when blades of high speed steel and bimetal type are to be tested; h) with a cutting speed of35strokes/min2strokes/min when blades of low alloy type are to be
27、tested; i) with location facilities for the test bar so that when the machine is stroking, the test bar is positioned no closer than50mm from the blade pin holes; j) which does not lift the reciprocating arm on the return stroke; k) which exerts static loads on the test bar at the top of the cut in
28、accordance withTable A.1. NOTEA commercially available light power hacksaw machine with gravity feed which is capable of meeting these requirements is described inB.1. Carbon k 0.06 % Silicon U 0.2 % k 1.00 % Manganese U 0.50 % k 2.00 % Chromium U 17.50 % k 19.00 % Nickel U 8.00 % k 11.00 % Sulfur k
29、 0.03 % Phosphorus k 0.045 %BS1919-2:1995 4 BSI 10-1999 A.3.2 Test machine for power blades A power hacksaw machine as follows: a) in good condition, particularly in respect of stroke alignment and freedom from excessive vibration; b) which cuts on the return stroke; c) which presents a blade at an
30、inclination of140 10 relative to the machine slides in the direction of cut (seeFigure B.2); d) with a machine speed of124 2cutting strokes/min; e) with a stroke length of133mm 1mm; f) with location facilities for the test bar so that when the machine is stroking the test bar is positioned no closer
31、 than50mm from the blade pin holes; g) with lift-off on the non-cutting stroke synchronized so that no dynamic load is applied during the non-cutting stroke, and so that no dynamic load relief is applied during the cutting stroke; h) which exerts static loads onto the test bar in accordance withTabl
32、e A.2; i) which supplies a coolant, consisting of100g/1 of Na 2 CO 3 .10H 2 Oin water, to the blade immediately above the test bar at a rate of2l/min minimum. NOTEA commercially available power hacksaw machine with a gravity feed which is capable of meeting these requirements is described inB.2. Tab
33、le A.1 Static load at top cut for hand blades Table A.2 Static load at top cut for power blades A.4 Preparation of test blades There is no preparation required for hand blades. Correct power blades to a length of350mm ifnecessary. NOTE1Power blades, because of their variation in length from300mm to4
34、50mm and the capacity limit of hacksawing machines, may need to be corrected to a blade length of350mm. A suitable procedure is described inB.5. NOTE 2Testing in the unaltered length is valid if the bow capacity of the machine allows, and alteration of blade clamping mechanisms in the machine is als
35、o feasible. A.5 Test procedure Calibrate the test machine to the loads given in Table A.1 for hand blades andTable A.2 for power blades. Once the load has been adjusted to give the load specified, ensure that the jaw of the test bar clamp that is nearest the main pivot of the machine remains in a fi
36、xed position, irrespective of the number of test bar strips being used in the blade testing. Position lengths of strip in accordance withTable 1 for hand blades, orTable 2 for power blades, edge upwards in the machine workpiece vice to form a pack approximately25mm deep. NOTEThe actual width of the
37、pack is determined by the number and thickness of strips given inTable 1 andTable 2. Position of bow Static load Kg Start of stroke Mid-stroke End of stroke 3.3 0.1 5.7 0.1 8.4 0.1 Position of bow Static load Kg Start of stroke Mid-stroke End of stroke 69 0.1 72 0.1 75 0.1BS1919-2:1995 BSI 10-1999 5
38、 A.6 Assessment of results Calculate the wear rate and total time as given in a) and b). a) Wear rate. Wear is represented by the recorded number of strokes plotted sequentially against section number. The average increase in wear per section cut is the slope of the plotted curve. A mathematical val
39、ue for this is derived by first performing a least squares linear regression which is designed to minimize the sum of the squares of the deviations of the actual recorded data points from the straight line of best fit and then calculating the slope of the line. This can be done automatically using a
40、 scientific calculator with linear regression facilities, or manually using the following formula: Use of a test sheet as shown in Figure C.1 andFigure C.2 simplifies the calculation for practical purposes. b) Total time. The total time shall be calculated by dividing the cumulative number of stroke
41、s for the allotted number of sections to be cut by the number of strokes per minute performed by the machine. A.7 Test report Cutting performance test results shall state the nominal dimensions and tooth pitch of the blade, the type of blade, the stroking rate per minute of the machine and the numbe
42、r of strips used in the pack of test bars. The following information shall be included in the test report: a) wear rate (to the nearest whole number); b) total time (to the nearest minute); c) number of cuts completed by the blade; d) amount by which the blade cut out of square (ifthe amount exceede
43、d3mm). Annex B(informative) Examples of equipment for testing hacksaw blades B.1 Machine for hand blade testing Commercially available power hacksaw machines may be used for performance testing but some modifications are essential to ensure reproducibility. 1) The dynamic loads generated by small ha
44、cksaw machines vary appreciably with variations in friction of the main slides; consequently the standard square slides fitted to machines should be replaced with two round slide bars running in linear re-circulating ball bearings. The housings for the bearings and the slide bar clamp should be jig
45、bored. To eliminate play, the two main pivot bearings should be replaced by phosphor bronze bearings. where C is the sum between n =1 and n = N; N is the number of cuts; n is the cut number; X n is the number of strokes per cut. 1) For information on the availability of proprietary hacksaw machines,
46、 write to Customer Services Information, BSI,389 Chiswick High Road, London. Wear rate NC nX n Cn CX n NCn 2 Cn () 2 - N n 1 = =BS1919-2:1995 6 BSI 10-1999 The static load exerted by the reciprocating arm including the connecting rod is measured by a spring balance hanging vertically above the test
47、bar, and attached to the blade with the bottom of the blade at the height of the top to a test bar, as shown inFigure B.1. During these measurements, the connecting rod pin is removed and replaced by a temporary loose pin of a smaller diameter. To eliminate the effect of friction in the main pivot,
48、it is necessary to take the average of two spring balance measurements, one for lifting and one for lowering. With the spring balance and the bow set in the correct positions, the bow is raised by hand and gently lowered until its weight is supported by the spring balance; the lowering load is then
49、measured. The “lifting” load is measured after the bow has been depressed by hand and gently allowed to rise. B.2 Machine for power blade testing A commercially available power hacksaw machine 2)can be utilized for performance testing but certain modifications are essential to ensure reproducibility. The modifications are as follows. a) To achieve adequate synchronization of the lift-off on the non-cutting stroke, the dash pot requires the following mo
