Crane Wire Rope

CRANE WIRE ROPE Maintenance, Inspection and Rejection Criteria

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Recommended Maintenance, Inspection and Rejection Criteria for Crane Wire Ropes 1. PURPOSE - GUIDE FOR INSPECTING CRANE WIRE The purpose of inspecting a crane wire rope is to supervise the normal process of deterioration so that rope can be removed from service before becoming a hazard to safety. Every wire rope will fail if it is not taken out of service at the appropriate time. If we select the right wire rope, we must understand the design and operation factors that influence the life of wire rope, where and how to detect changes in wire rope conditions, how to maximize rope life cycle and avoid a reoccurrence of same failures (provide safe and economic operation). Some sections of wire rope will go through a greater number of bends over sheaves and drums than the rest. The area that has higher number of cycles requires a close examination. Very few if any offshore crane ropes are discarded through pure bend fatigue and the majority of ropes are discarded due to mechanical/drum damage, either as a result of crushing or plucking of the wires at the spooling cross-over regions due to abrasion. Corrosion is also a prime mode of rope deterioration offshore and to extend rope service life demands good inspection, maintenance and rejection criteria based on the approved standards. It is essential to have and maintain a crane wire inspection program and be able to assess wire rope and crane history. When crane wire is replaced, it is as essential as replacing old wire with new, to investigate why, what factors influenced wire deterioration and determine if anything can be done to extend life of wire rope. This must be recorded and shared with rest of fleet as well as the crane and wire manufacturer. (There is no benefit in replacing wire rope that will fail the same as the previous one.)

Standard ropes

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Inspection and rejection criteria are based on the ISO 4309 Code of practice for the examination and discard of the crane wire rope. The discard criteria from ISO 4309 are explained also in this bulletin. Specialty ropes Internal inspection of specialty wire ropes may require NDT methods, to be determined by the wire rope examiner. For external inspection standard methods apply. Applicable standards ISO 4308-1 Cranes and Lifting Appliances – Selection of Wire Ropes ISO 4309 Cranes – Wire ropes – Code of practice for examination and discard BS 6570 The Selection, Care and Maintenance of Steel Wire Ropes EN 10264 – 2002 Steel Wire and Wire Products – Steel wire for ropes API 2D Recommended practice 2. DAILY 3. VISUAL DAILY INSPECTION BY OPERATOR Visual inspection of critical points by operator: Special attention should be given to sections of ropes that run over sheaves and drums, including parts that are located next to the compensating assemblies and anchor points. Plus sections of rope that become wet or that are exposed to heat and aggressive environment (salt water, exhaust gases, dust from cement, barites and other chemicals) 4. MONTHLY Check the over-all condition of all of the wire ropes, including the end terminations. Inspect the reeving. configurations of the wire ropes of the crane, to see if they comply with the manufacturer’s recommendations. (Wherever possible the reeving should be symmetrical, this is for reasons of safety, plus for getting the optimum longevity of service life from both sheaves and wire rope together). * Non-Symmetrical Reeving, especially the “Laced-Block” type is a poor excuse for crane rigging and reeving practices. It should be avoided, as it contributes to premature sheave and wire rope wear, as well as being a contributing factor to the adverse side loading of certain types of crane booms under certain operating circumstances.

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Complete filling in the crane wire rope examination/discard record report. Using a Vernier Caliper Gauge, measure rope diameter (always-select the part of the rope that travels the most through sheaves – each crane will be specific according to the operational conditions and reeving). Check all rope terminations for damage, wear, fatigue, corrosion, broken wires, and the termination’s arrangement components and fasteners(i.e: bolts, nuts, wedges and clamps) If required lubricate wire rope using pressure lubricator. 5. ANNUAL The person having completed a recognized wire rope examiner’s course shall perform the annual inspection and complete the crane wire examination/discard record. If the condition of wire rope is acceptable in accordance with ISO 4309 and there are no broken wires, the rope can safely continue to be used up to a maximum service life of three years. In some instances NDT methods might be needed to safely extend useful life of the rope. The wire rope inspector shall determine if NDT is required. If NDT is used to extend/reject life of the rope a copy of the NDT record has to be included in the inspection/rejection report. If there is indication of wire rope deterioration necessitating discard of the said wire rope it shall be in accordance with the criteria as described in section 3.5 of the Code of Practice ISO 4309. However, as a new simplified user-friendly version of ISO 4309 is due out in the near future, SPDC then with the present ISO 4309, would recommend (after discussion with Bridon Ropes) using the following nine points of consideration when inspecting wire ropes. These nine points are more in line with the contents of the new COP than the current one, hence our recommendation to use them for wire rope inspection. They are all, of course, based on ISO 4309. They are as follows: 1. Randomly distributed broken wires. 2. Wear both internal & external and for abrasion. 3. Localized groups of broken wires. 4. Broken wires at the termination. 5. Deterioration of the rope core. 6. Thermal damage. 7. Corrosion - Internal.

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8. Corrosion external. 9. Rope deformations. The above 9 points can then be split in to three categories; for the first category 1 & 2, the inspector needs to count the randomly distributed broken wires and if the discard figure is reached, the rope rejected or otherwise left in service. For the second category 3, 4, 5, 6 & 7, it is a simple situation of if it is seen the rope should be rejected, if not the rope remains in service. For the third category 8 & 9, if these are seen, the inspector needs to make a judgment as to how severe it is and should the rope remain in service. We can now consider the individual points, knowing the crane ropes selected incorporate plastic to primarily, increase bend fatigue life, reduce reduction in diameter and prevent internal contamination. 1. Randomly distributed broken wires • For the main and auxiliary hoists (Dyform 34LR-PI), if 2 or more visible broken wires are found over a rope length of 6d or if 4 or more visible broken wires are found over a rope length of 30d, the rope should be discarded. • For the boom hoists (Dyform 8x19-PI), if 5 or more visible broken wires are found over a rope length of 6d or if 10 or more visible broken wires are found over a rope length of 30d, the rope should be discarded. • For the boom hoists (Dyform 8x26-PI), if 9 or more visible broken wires are found over a rope length of 6d or if 18 or more visible broken wires are found over a rope length of 30d, the rope should be discarded.

• For the boom hoists (Dyform 8x36-PI), if 12 or more visible broken wires are found over a rope length of 6d or if 24 or more visible broken wires are found over a rope length of 30d, the rope should be discarded. • Randomly visible broken wires are assumed to be the result of bend fatigue and therefore should be evenly distributed over the length of rope experiencing the most bending over sheaves. 2. Wear both internal & external and for abrasion - if the rope diameter is reduced by (3% for main & auxiliary) (7% for boom) or more from the nominal rope diameter, the rope should be discarded. Any reduction in the rope diameter

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generally results from wear or abrasions both internally and externally, break down of the plastic, excessive loadings, etc and can easily be measured. The nominal rope diameter is used because this is the value quoted on the test certificate and therefore the only value easily available to the rope inspector. Some customers refer to the actual rope diameter, the diameter the rope measures when it is first installed, but we believe the nominal value is more acceptable to use. Values given in 1 & 2 above are based on ropes operating in steel sheaves or ropes operating in plastic sheaves in combination with multi-layer coiling. They do not apply to ropes operating in plastic sheaves in combination with single layer coiling. 3. Localised groups of broken wires - if a localised group of two or more wires are found, the rope should be discarded. Groups of broken wires are normally associated with mechanical damage and/or unusual events having taken place because of the lack of knowledge as to how the broken wires occurred. 4. Broken wires at the termination - if two or more broken wires are found in the vicinity of the termination, the rope should be discarded. A careful check for broken wires needs to be made around the rope entry to the fitting as wire breaks can easily occur just inside the fitting and the first signs of a broken wire will be a looseness of those wires. 5. Deterioration of the rope core - if any signs of core deterioration are found, the rope should be discarded. The most obvious sign of any core deterioration is a localised reduction in rope diameter. 6. Thermal damage - if any signs of a rope having been subjected to heat is found, the rope should be discarded. This is on the basis that the rope inspector has no knowledge as to what temperature the rope has been subjected and therefore can not determine what the effect on the rope would be. The first sign of a rope having been subjected to heat is a localised loss of lubricant from the rope / a dry section. The individual wires will discolour and the plastic may melt out between the strands, other sources of heat are welders, either the effects of weld splatter or more likely earthing of the rope. 7. Internal corrosion - if any signs of internal corrosion are found, the rope should be discarded. Although it is difficult to check for internal corrosion with these 'plastic' ropes, (Generally Bridon recommends that all non-plastic ropes should be opened up as part of a thorough inspection to determine the condition of the core) the inspector can look for any signs of red powder (iron oxide) appearing between the strands worked out from the inside of the rope, check the ropes flexibility, but both of these will be difficult with plastic inside the rope and possible considered not appropriate.

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8. Corrosion external - if external corrosion is found, it is normally the judgment of the inspector to determine the level of severity and to decide if the rope should remain in service or not. 9. Rope deformations - if rope deformations are found, it is normally the judgment of the inspector to determine the level of severity and to decide if the rope should remain in service or not. The most important thing is to record and detail clearly the results of the examination and to produce a record that allows the cumulative effect of points 1, 2, 8 and 9 above to be taken in to account. Furthermore, we advise using the preceding nine points of wire rope inspection at least until the new edition of ISO 4309 is in use. However, the present Section 3.5 of ISO 4309 is as follows: 3.5.1 Nature and Number of Broken Wires In the case of 6- and 8-strand ropes, broken wires occur principally at the external surface. This does not apply to wire ropes having a number of layers of strands (Typically multi-strand constructions), where the majority of breaks occur internally and are therefore “non-visible” fractures Tables 1 and 2 take these factors into consideration when considered in conjunction with the factors given in 3.5.2 to 3.5.11 When establishing rejection criteria for rotation-resistant ropes, consideration shall be given to the rope construction, length of service and the way in which the rope is being used. Guidance to the number of visible broken wires which shall give rise to rejection is given in table 2. Particular attention shall be paid to any localized area which exhibits a dryness or denaturing of the lubrication.

Table 1 - Guidance for the number of broken wires in round strand ropes working in steel sheaves

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Table 2 - Guidance for the number of broken wires in rotation-resistant ropes working in steel sheaves

3.5.2 Broken Wires at Termination Broken wires at, or adjacent to, the termination, even if few in number, are indicative of high stresses at this position and may be caused by incorrect fitting of the termination. Investigation of the cause of this deterioration shall be made, and, where possible, the termination should be remade, shortening the rope if sufficient length remains for further use. The termination should be done only by qualified personnel. 3.5.3 Localized grouping of broken wires Where broken wires are very close together, constituting local grouping of such breaks, the rope shall be discarded. If the grouping of such breaks occurs in a length less than 6d or is concentrated in any one strand, it will be prudent to discard the rope even if the number of wire breaks is smaller than the maximum number indicated in tables 1 and 2. 3.5.4 Rate of increase of broken wires In applications where the predominant cause of rope deterioration is fatigue, the commencement of broken wires will begin after a certain period of usage, but the number of breaks will progressively increase at ever-shortening intervals.

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In these cases, it is recommended that careful examination and recording of the increase of broken wires should be undertaken with a view to establishing the rate of increase of the breaks. An application of this “law” may be used in deciding the future date for rope discard.

3.5.5 Fracture of strands Small deterioration may not be so apparent from normal examination, particularly if the rope stresses are well balanced throughout the individual strands. However, the condition may result in a high loss of rope strength, so that any suggestion of such internal deterioration shall be verified by internal examination procedures. Where such deterioration is confirmed, the wire rope shall be discarded (see annex D) 3.5.6 Reduction of rope diameter resulting from core deterioration Reduction of rope diameter resulting from deterioration of the core can be caused by a) Internal wear and indentation; b) Internal wear caused by friction between individual strands and wires in the rope, particularly when it is subject to bending; c) Deterioration of a fibre core; d) Fracture of a steel core; e) Fracture of internal layers in a multi-strand construction. If these factors cause the rope diameter (average of two diameter measurements normal to each other) to decrease by 3 % of the nominal rope diameter for rotation resistant ropes, or 10 % for other ropes, the ropes shall be discarded even if no broken wires are visible. 3.5.7 External wear Abrasion of the crown wires of outer strands in the rope results from rubbing contact, under pressure, with the grooves in the pulleys and the drums. The condition is particularly evident on moving ropes at points of pulley contact when the load is being accelerated or decelerated, and shows itself as flat surfaces on the outer wires.

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Wear is promoted by lack of lubrication, or incorrect lubrication, and also by the presence of dust and grit. Wear reduces the strength of ropes by reducing the cross-sectional area of the steel. When owing to external wear the actual rope diameter has decreased by 7 % or more of the nominal rope diameter, the rope shall be discarded even if no wire breaks are visible. 3.5.8 Decreased elasticity Under certain circumstances usually associated with the working environment, a rope may sustain a substantial decrease in elasticity and will be unsafe for further use. If a complete strand fracture occurs, the rope shall be discarded. Decreased elasticity is difficult to detect: if the examiner is in any doubt, advice should be obtained from a specialist in ropes. However, it is usually associated with the following: a) Reduction of rope diameter; b) Elongation of the rope lay length; c) Lack of gap between individual wires and between strands, caused by the compression of the component parts against each other; d) The appearance of fine, brown powder within the strand gussets; e) While no wire breaks may be visible, the wire rope will be noticeably stiffer to handle and will certainly have a reduction in diameter greater than related purely to wear of individual wires. This condition can lead to abrupt failure under dynamic loading and is sufficient justification for immediate discard. 3.5.9 External and internal corrosion Corrosion occurs particularly in marine and industrial polluted atmospheres, and will not only diminish the breaking strength by reducing the metallic area of the rope but will also accelerate fatigue by causing the irregular surface from which stress cracking will commence. Severe corrosion may cause decreased elasticity of the rope. a) External corrosion Corrosion of the outer wires may be detected visually. b) Internal corrosion (see annex E, plate 7) This condition is more difficult to detect than the external corrosion which frequently accompanies it, but the following indications may be recognized:

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1) Variation in rope diameter. In positions where the rope bends around pulleys, a reduction in diameter usually occurs. However, in stationary ropes it is not uncommon for an increase in diameter to occur due to the build-up of rust under the outer layer of strands; 2) Loss of gap between the strands in the outer layer of the rope frequently combined with wire breaks in the strand gussets. If there is any suggestion of internal corrosion, the rope should be subjected to internal examination as indicated in annex D; this shall be carried out by a competent person. Confirmation of severe internal corrosion is justification for immediate rope discard. 3.5.10 Deformation Visible distortion of the rope from its normal formation is termed “deformation” and may create a change at the deformation position which will result in an uneven stress distribution in the rope. Distinction is made between the following main deformations of rope on the basis of their appearance (see 3.5.10.1 to 3.5.10.9): a) Waviness b) Basket or lantern distortion c) Strand extrusion d) Wire extrusion e) Local increase in the diameter of the rope f) Local decrease in the diameter of the rope g) Flattened portions h) Kinks or tightened loops i) Bends

3.5.10.1 Waviness (see annex E, plate 8) Waviness is a deformation where the longitudinal axis of the wire rope takes the shape of a helix. While not necessarily resulting in any loss of strength, such a deformation, if severe, may transmit a pulsation resulting in irregular rope drive. After prolonged working, this will give rise to wear and wire breaks. In the case of waviness (see figure 1), the wire rope shall be discarded if:

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d 1 > 4d / 3 Where d is the nominal diameter of the rope and d1, is the diameter corresponding to the envelope of the deformed rope, and the length of the rope under consideration does not exceed 25d.

Figure 1 waviness.

3.5.10.2 Basket or lantern distortion (see annex E, plate 9) This condition occurs in ropes having a steel centre (or core) when the outer layer of strands has become dislocated, or when the outer layer becomes longer than the inner layer of strands. Such a condition may occur as a result of abrupt (snatch) loading of the rope from a slack condition. A basket or lantern formation is justification for immediate discard. 3.5.10.3 Strand extrusion (see annex E, plate 10) This feature is frequently associated with basket or lantern deformation where the rope imbalance is indicated in the extrusion of the core. Strand extrusion is justification for immediate discard. 3.5.10.4 Wire extrusion (see annex E, plates 11 and 12) In this condition, certain wires or groups of wires rise up, on the opposite side of the rope to the pulley groove, in the form of loops - this feature usually results from shock loading. If the deformation is severe, there is justification for rope discard. 3.5.10.5 Local increase in diameter of rope (see annex E, plates 13 and 14)

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A local increase in rope diameter may occur and could affect a relatively long length of the rope. The condition usually relates to a distortion of the core (in particular environments, a fibre core can swell up owing to the effect of moisture) and consequently it creates imbalance in the outer strands, which become incorrectly oriented. A severe condition is justification for rope discard. 3.5.10.6 Local decrease in diameter of rope (see annex E, plate 17) A local decrease in the diameter of the rope is frequently associated with fracture of a core. Positions close to terminations shall be carefully examined for such deformations. A severe condition is justification for rope discard. 3.5.10.7 Flattened portions (see annex E, plates 18 and 19) Flattened portions occur as a result of mechanical damage; if severe, they are justification for rope discard. 3.5.10.8 Kinks or tightened loops (see annex E, plates 15 and 16) A kink or tightened loop is a deformation created by a loop in the rope which has been tightened without allowing for rotation about its axis. Imbalance of lay length occurs, which will cause excessive wear, and in severe cases the rope will be so distorted that it will have only a small proportion of its strength remaining. A kink or tightened loop is justification for immediate discard. 3.5.10.9 Bends (see annex E, plate 20) Bends are angular deformations of the rope caused by external influence. The condition is justification for immediate discard. 3.5.11 Damage due to heat or electric arcing Wire ropes which have been subjected to exceptional thermal effects, externally recognized by the colours produced, shall be discarded.

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Whilst inspecting the wire ropes, all the other reeving components in the system, shall be examined, including sheaves, drums, rollers, end terminations or any other part that is directly or indirectly associated with wire rope arrangement.

Note: Installation procedure of new wire rope is to be followed as per crane wire rope and crane manufacturer recommendations. However, when installing Metric crane wire ropes onto the older American made Cranes, that usually have the wider, but smaller diameter, smooth (no grooved) drums, which were originally designed for use with API Spec/Imperial measurement ropes. The following recommendations should be adhered to: ♦ Care and diligence must be exercised when winding the rope onto the drum at the correct tension. ♦ Which is a minimum tension of 10% of SWL, based on a 5:1 design factor. ♦ Or, in other words, 2% of the MBL of the rope. ♦ The reason for the precautionary request for diligence is two-fold: (1) for safety and (2) because of the potential problems that any incompatibility between metric rope and imperial sized drum. ♦ The best tool to use to hold the correct tension on the line being wound onto the drum, is a “pinch-roller” type line tensioner in conjunction with a Martin Decker Load Cell. ♦ As the bottom layer of wraps are wound upon the drum under tension, they should be carefully “blocked” hard against each other and up against the flange of the drum the first wrap is anchored to. (To avoid cable damage, this should be done preferably with a ‘soft’ Mallet, or if not, a wooden 2”x4” and a hammer) ♦ As the wraps being would onto the drum, fill the bottom layer of the drum, any gap between the last wrap of the layer and the other drum flange should be filled in with soft line tapped in hard carefully with a hammer or Mallet and taped in position with duct tape, for safety. ♦ The other layers on the drum, above bottom layer will spool correctly now, but should still be put on at the minimum recommended tension.

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During new wire rope installation total length of wire rope is to be lubricated using pressure lubricator. A recognized inspector can be 3rd party or rig personnel that have completed a recognized wire rope examiner’s training course. CRANE WIRE ROPE INSPECTION/DISCARD LOG

(to be completed monthly/annually)

DESIGN FACTORS INFLUENCING FATIGUE LIFE OF THE WIRE ROPE ♦ Design factor Are controlled by the crane manufacturer, with factors like sheave specification, Diameter of Tread to diameter of rope ratio, type of bearings, sheave’s groove radii and throat angles versus fleet angles of hoist lines, contact angles, tensile strength, bends and others ♦ Operating factors Are: The installation and breaking-in of the rope, the safety factor it is operated at load wise, Inadvertent shock-loading, lubrication, inspection and maintenance OPERATING FACTORS INFLUENCING FATIGUE LIFE OF THE WIRE ROPE ♦ Storage Wire ropes shall be stored in the warehouse, or an equivalent protected controlled environment. They have to be protected from all of the elements of nature: sun, rain, sleet, snow, humidity and exposure to a marine environment. Reels of any wire rope that has been heavily lubricated at each stage of its manufacture (Winding, stranding & closing) do need to be turned on a regular basis to prevent migration of the lubricant. ♦ Installation Prior to installing any new wire rope, inspect sheaves and drums. Ensure that the drums and sheaves are in the good conditions (there are no advantages to install new rope in worn or damaged sheave’s and drum grooves). If any wire rope has to be discarded prematurely, or for any reason other than fair wear and tear, then the

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cause of the rope’s demise needs to be investigated, resolved, explained and documented. While installing new rope ensure that complete length of the rope is lubricated using “Masto” pressure lubricator. This will ensure that any moisture is removed and total length of rope is properly lubricated. If pressure lubrication is not applied, moisture can become corrosion which can greatly reduce life of the wire rope. Wire rope should be installed under as much load as possible. The amount of load recommended is approximately 5-10% of minimum breaking load. Insufficient tension on the bottom wraps can create a multitude of problems. The absolute minimum of tension that a wire rope should be wound onto a drum at, is 10% of SWL, based on a design factor of 5. Which equates to 2% of minimum breaking load. Also on smooth drums, especially those, that for the majority of their operating time are in a single layer operating mode, the correct lay of rope for the type of wind and the direction of spooling is very important. And should be as follows: a) Over-wind left to right, use right lay rope. b) Under-wind right to left, use right lay rope.

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FIGURE 1 CORRECT METHOD FOR LOCATING THE ROPE ANCHORAGE POINT ON A DRUM. c) Over-wind right to left, use left lay rope. d) Under-wind left to right, use left lay rope. (The above directions of spooling per rope lay, apply with the observer standing behind the drum and looking towards the direction of rope travel).

The reason for this is: When a rope onto a drum, any tendency for the rope to twist when tension is released, will be in a direction that would untwist the rope at the free end. So the advantage in applying the rope in proper direction of lay is that when the load is slacked off, the several coils of rope on the drum will hug together and maintain a level and even layer. However, with rope in improper direction of lay, each time that the load is slacked off, the coils will spread apart and when the winding of the rope back onto the drum resumes, it often results in the rope criss-crossing, overlapping and drum-crushing or flattening the unevenly spread coils on the drum. The reel of the new wire rope and the first sheave must rotate in the same direction to avoid reverse bend reeving and installation of a twisted rope. (In other words reeve the crane from the reel to first sheave correctly either ‘over-wind’ to ‘over-wind’, or ‘under-wind’ to ‘under-wind’) as appropriate. When installing a new rope on a crane, the objective of the exercise is to install/reeve the new rope without inducing any turn into it. Whether reeving the new rope with the old rope that it’s replacing, or by using a messenger line (which should be suitably torque-matched to the new rope). Join the two together with a wire stringing grip (also known as a ‘snake’, ‘sock’, ‘Chinese finger’) DO NOT USE A SWIVEL TO JOIN THE 2 HALVES OF THE ‘SNAKE’ TOGETHER DURING THE INSTALLATION OF THE ROPE. The new rope should be marked or ‘flagged’ so that during reeving, any ‘turn’ can be monitored and taken out prior to the rope being anchored to the drum. ♦ Breaking in It is advisable when starting to use a new rope to let it set itself to the working conditions by running it without a load and then for short period with light load.

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♦ Operation Avoid kinks, shock-loading, over and cross winding. ♦ Re-lubrication When installing new rope and as required use “Masto” pressure lubricator. ♦ Slip and cut If capacity of drum allows extra wire consider slip and cut.

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