A shear blade is a rectangular section of tool steel with four usable edges, and a hold-down system is a row of urethane-tipped feet. The short answer: blades travel laid flat in a single layer with the edge facing inward or upward, fully supported along their whole length, never stacked directly on each other and never left spanning; hold-down feet must be relieved of hydraulic pressure or mechanically limited so that residual force cannot press a permanent hollow into the urethane; and the case needs genuine moisture and corrosion control. Blade straightness sets the flatness of the sheared face and the burr height. As a practical figure, once an upper blade deviates more than about 0.1 mm per metre, thin sheet develops visible roll-over and a torn fracture band — and a deviation created by transport stress can only be removed by re-grinding or replacing the blade.
Shearing machines that travel long distances or ship for export are usually split into separate consignments: blades, hold-down assemblies, back gauge and accumulator travel in their own cases and are re-assembled and re-gapped on site. That stage looks like simple handling but reliably produces two kinds of dispute. The first is an edge nicked by another hard item in the case, which afterwards leaves a repeating score line on every sheared sheet. The second is a hold-down cylinder pushed out or compressed while the machine is unpowered, so that after reassembly the clamping force is uneven and the sheet creeps during the cut. This article works component by component through fixturing, temporary locking, corrosion protection, liner proportioning and acceptance criteria.
Contents
- Four risk points in split-shipment of shearing machines
- Blades: protecting both the edge and the straightness
- Blade beds and holders: bearing faces that cannot be bruised
- Hold-down systems: hydraulic and spring types need different treatment
- Blade beams and guideways: long members must never span unsupported
- Safe depressurisation of accumulators and hydraulic cylinders
- Temporarily locking the blade gap adjustment
- Rust and moisture: carbon steel blades alongside cast iron parts
- Liner materials: balancing contact layer against load-spreading layer
- Case ingress rating and pressure equalisation
- Test references and packaging markings
- Sizing by blade length and component mass
- Frequently Asked Questions
- Conclusion and further reading
Four risk points in split-shipment of shearing machines
Edge chipping comes first. Shear blades are commonly made from 6CrW2Si, Cr12MoV or H13-class steels hardened to roughly HRC 54 to 58, with a 90-degree edge angle. High hardness with low toughness means the edge is extremely sensitive to point contact: an unsecured bolt, a dropped hold-down pad, anything loose in the case can knock a chip out of it during handling. Past about 0.1 mm of chip depth, thin sheet comes away with a visible tear along the cut.
Blade bending comes second. A blade over four metres long can weigh 80 to 150 kg on its own. If the case supports it on a single timber block at mid-length, both ends sag under their own weight, and sustained stacking load turns that sag into a permanent bow. Once a blade is bowed the gap setting loses its reference: a gap that measures correctly at both ends will be wide or narrow in the middle.
Hold-down foot deformation and hydraulic leakage take third and fourth place. Urethane-tipped feet creep downward under residual cylinder pressure and take a permanent hollow; an accumulator that was never relieved will also change nitrogen pressure as ambient temperature rises, producing unexpected return-stroke thrust. Fluid weeping from an open port leaves an oil film inside the case, which accelerates blade corrosion.
| Risk point | Sensitive components | Immediate cause | First-line countermeasure |
|---|---|---|---|
| --- | --- | --- | --- |
| Edge chipping | Upper and lower blade edges | Impact from hard items, edge bearing load | Edge sleeves, edge facing inward, single-layer storage |
| Loss of straightness | Long blades, blade beam | Too few supports, direct stacking | Full-length even support, no stacking |
| Hold-down pad hollows | Hold-down feet, urethane pads | Residual pressure, case compression | Depressurise, stroke limiting, blocking pads |
| Oil film and rust | Blades, beds, cylinder bodies | Open ports, moisture ingress | Port plugs, absorbent layer, desiccant |
These four are coupled rather than independent. An oil film lowers friction and lets a blade slide more freely inside its cavity, and that extra freedom raises the chance of the edge striking something hard. Cleanliness and restraint therefore belong at the same level of the design discussion, not in sequence with restraint first and cleanliness later.
Blades: protecting both the edge and the straightness
Blade fixturing comes down to two requirements, and neither can be traded away: orientation and support.
For orientation, a blade travels flat, in a single layer, with the cutting edge facing inward toward the cavity wall or facing upward. Edge down is the worst arrangement, because the entire mass then passes through the edge into the case floor, which is exactly the loading a brittle edge cannot take. Where two blades must ship together, insert a full-length rigid separator between them, with bearing area covering the entire blade length.
For support, lay the blade on a bearer strip of the same length, then place support blocks under that strip at no more than 500 mm centres. That spacing is tighter than for a general shaft because the blade section is small and its section modulus correspondingly low, so the same span produces much more deflection. A four-metre blade is better served by nine or more support points.
Practical check: with the blade seated in the liner, press down at mid-length and release. Visible spring-back or an audible knock against the cavity wall means the support is insufficient and needs to be densified.
Edge sleeves are the second line of defence. Polyurethane or nylon works well, with the sleeve 20 to 30 mm longer than each blade segment and a hardness around Shore A75 to A90. Because a shear edge is a right angle, the sleeve bore should be a matching square groove rather than a radiused one — a round bore gives the edge only a line of contact and actually concentrates pressure at that line.
Long blades need a lifting aid or two-person carry during loading and unloading, so the case walls should include hand holds or lifting apertures. Hand hold positions must account for the centre of gravity, which sits near the geometric centre for a bare blade but shifts toward the bed when blade and bed ship as a set.
Blade beds and holders: bearing faces that cannot be bruised
The blade bed carries the lower blade; the blade holder clamps the upper blade. Both carry several precision mating faces and are castings or machined parts of comparatively modest stiffness. The usual damage pattern is a bearing face bruised into hollows with chipped edges, after which the blade can no longer seat along its full length and the shear gap becomes uneven.
Orient the bed so that its bearing face points up or to the side, keeping it out from under the weight of anything above. If stacking is unavoidable, cover the bearing face with a 3 to 5 mm medium-hardness rubber sheet before adding a rigid separator board, so that point loads become distributed pressure.
Metal chips collect readily in holder locating grooves and clamp bolt holes. Blow these out with compressed air before packing, then mask the groove openings with rust-inhibiting paper or self-adhesive protective film. Choose film carefully: a non-residue PE film is preferable to ordinary clear tape, because tape leaves an adhesive layer that is difficult to remove after a hot summer in transit and adds cleaning work before commissioning.
Beds and holders are classic multiple-identical-part components, well suited to removable divider systems that give each item its own compartment. Compartment width should exceed the part width by 2 to 3 mm — enough to stop movement, not enough to make extraction awkward. Divider assembly methods and groove machining requirements are covered in removable divider systems inside protective cases.
Hold-down systems: hydraulic and spring types need different treatment
Hold-down systems contain the largest number of actuating elements on a shear. A six-metre hydraulic guillotine typically carries twelve to sixteen hydraulic hold-down cylinders, each with a urethane foot. Spring-type hold-downs are mechanically simpler but far more sensitive to their pre-loaded state.
For hydraulic hold-downs the sequence is depressurise, limit, cushion. Depressurise means releasing system pressure completely and confirming no residual pressure at the return line. Limit means inserting equal-height blocking pads between the feet and the table so the feet cannot creep down inside the case. Cushion means adding a soft layer under the feet to absorb handling vibration.
Spring hold-downs need more care. The springs are already compressed on assembly, and any additional compression during transport produces permanent set, which directly changes clamping force. The proper approach is to release pre-load with a temporary relieving fixture until the springs sit close to free length, then pack. If that is not practical, fit rigid limit sleeves at both ends of each spring so the compressed length is locked at the assembled value.
| Hold-down type | Action before packing | Restraint in the case | Checks after reassembly |
|---|---|---|---|
| --- | --- | --- | --- |
| Hydraulic cylinder | Fully depressurise, confirm return line clear | Equal-height blocking pads under the foot | No weeping, no piston rod distortion |
| Spring hold-down | Relieve pre-load or fit limit sleeves | Rigid limits at both ends, body restrained | Free length, clamping force consistency |
| Urethane foot | Clean, inspect pad face | Individual pocket, pad face up | No hollows, hardness and resilience normal |
| Hold-down beam | Check straightness, clean | Even support along full length | Base straightness, contact with the table |
Hold-down pads are usually polyurethane or nitrile rubber and count as wear items. Packed loose alongside sharp components they get cut and grooved, and afterwards they mark the sheet surface during clamping. Give each foot its own pocket with the pad facing up and keep at least 30 mm of clearance from any metal component.
Blade beams and guideways: long members must never span unsupported
The blade beam carries the upper blade and also travels on the guideways, so it is both a long member and a precision member, and its transport protection has to satisfy two requirements at once: no unsupported span, and no marking of the guideway faces.
For support, follow the same logic as for blades: distribute supports along the full length at no more than 600 mm centres. Because the beam is stiffer than a blade the spacing can be slightly wider, but neither end should overhang a support by more than 300 mm.
To protect the guideway faces, fit soft protector strips or sleeves over the mating surfaces and keep 2 to 3 mm of soft isolation between beam and guideway. Where beam and guideway ship as one assembly, fit transport lock blocks at both ends of the guideway and park the beam at one end of its stroke so it cannot shuttle during transport.
The drive side of the beam usually carries cylinders or a rack-and-pinion arrangement, and the linkage and pin joints wear under vibration. Coat these joints with corrosion-inhibiting grease and wrap them in stretch film before dispatch, then wipe clean at commissioning.
Safe depressurisation of accumulators and hydraulic cylinders
The accumulator is the most frequently overlooked component on a shearing machine and also the one with the clearest safety consequence. A nitrogen accumulator stores energy in its charged state, and rising ambient temperature during transport raises nitrogen pressure further. If the case is also sealed, the combination can put unexpected thrust into the return circuit.
Three actions must be completed before dispatch. First, reduce nitrogen pressure to a safe value or discharge it entirely, following the machine manual. Second, drain the return cylinders and plug their ports. Third, fit a temporary mechanical lock in the circuit so that a return cylinder cannot move under its own weight when unpressurised.
If the accumulator cannot be discharged on site, it should not travel inside the case at all. Treat it as a pressure vessel consignment with its own documentation and markings, and confirm whether it falls within dangerous goods classification. The classification principles for pressure-containing components are discussed in dangerous goods transport case classification and marking.
Piston rods are precision components and their plating is damaged easily; once scored, they weep. Coat the exposed rod with corrosion-inhibiting grease, then fit a soft sleeve covering the full exposed length with at least 20 mm of extra clearance.
Temporarily locking the blade gap adjustment
Shear gap is set through an eccentric shaft, a wedge or a screw mechanism, with adjustment measured in hundredths of a millimetre. In the free state these mechanisms respond to vibration and creep slowly, which shows up after reassembly as a gap that differs between the two ends of the same blade pair.
Locking takes two steps. First, set the adjusting screw or eccentric to the assembled position and secure it with nylon ties or a temporary clamp plate. Second, insert thin shims between the adjusting faces to raise friction, so that vibration does not act directly on the locking device. Every temporary locking item needs a conspicuous removal tag in oil- and heat-resistant material so it cannot fall off in transit.
Limit switches, proximity sensors and encoders are the feedback elements of the gap mechanism and should be removed and packed separately, or protected with a rigid guard. Their sensing faces are extremely fragile and a single compression can shift the output signal. If they must travel in the same case, they belong in their own recess with a guard fitted; they must never rest directly against a casting surface.
Rust and moisture: carbon steel blades alongside cast iron parts
Most shearing machine components are carbon steel or cast iron, and corrosion is a serious risk on sea freight. Rust is not only cosmetic: it changes the seating condition between blade and bed, which is why corrosion control in a shearing machine case ranks as high as cushioning.
Corrosion protection has three tiers. The first is coating — apply corrosion-inhibiting grease or oil to non-cutting blade faces, bed bearing faces and piston rods. The second is wrapping — enclose with VCI paper or film to create a local vapour-phase environment. The third is humidity control — add desiccant and keep the case's moisture transmission rate low.
Vapour-phase corrosion inhibitor paper works well on cast iron, but its two operating rules are often missed. The distance between the wrapped surface and the VCI paper should generally not exceed 300 mm, and the wrap should be as sealed as possible, otherwise the vapour-phase inhibitor escapes before it can act. For slender items such as blades, wrapping with VCI paper and then seating the wrapped blade in its cavity works better than loose sheets.
Size the desiccant from the internal volume with a safety margin. Remember that desiccant stops working once saturated, and its effective life shortens considerably if the case is opened repeatedly in transit. Where the case also contains electronics or precision guideways, prevent desiccant dust from reaching the moving pairs.
Avoid unprotected plain carbon steel as internal hardware. If metallic reinforcement is needed inside the liner, specify galvanised or stainless material, or a coated finish, so that galvanic corrosion cannot start.
Liner materials: balancing contact layer against load-spreading layer
A shearing machine case liner performs three functions at once — cushioning, locating and corrosion protection — so its material build-up differs from that of a purely shock-absorbing case.
For the contact layer, use flocked fabric or a soft polyurethane film, 1 to 3 mm thick. Its only job is to protect machined faces, so it must be soft, must not contain plasticiser that can migrate, and must not shed particles. Shedding matters more here than in most applications, because particles that reach blade clearance directly degrade cut quality.
For the locating layer, use moulded EVA or PE milled to the component profile. Shearing machine components are geometrically simple — long bars and blocks — so cavity design concentrates on continuous support along the length rather than complex three-dimensional enveloping.
For the load-spreading layer, use 20 to 30 mm of PE or EVA sheet, which converts point loads into distributed pressure. Thickness should be matched to case stiffness: a stiff shell allows a thinner layer, a flexible shell demands a thicker one.
For the cushioning layer, use closed-cell foam 20 to 30 mm thick against the case walls. Closed cell is preferable here because it absorbs less moisture, which supports the corrosion-control objective. Moisture uptake and rebound behaviour across foam types is compared in case foam material comparison and selection.
Where several component types share one case, work to three rules: heavy items in the lower layer, long items oriented lengthwise, small items in individual pockets. Every layer must transmit its load directly to the case floor rather than stacking onto the machined face of the component below.
Case ingress rating and pressure equalisation
The sealing requirement for a shearing machine case is driven mainly by moisture rather than water. Inside a sea container, day-night temperature cycling produces condensation, and any steel component will show rust spots where it forms. Judge the rating to GB/T 4208 or IEC 60529; for sea freight IP67 is a sensible target, combined with active humidity control inside the case.
Three questions decide the level quickly. Could the case be rained on or hosed down? Does it contain uncoated cast iron or carbon steel surfaces? Will more than two weeks pass between delivery and commissioning? Any yes answer argues for a higher rating.
Sealing addresses water vapour entering from outside, but it does not deal with moisture already inside or with condensation driven by temperature cycling. That is why a pressure equalisation valve belongs in the design: it lets the pressure difference between inside and outside equalise slowly, so the gasket is not sucked open and the shell does not distort. Valve selection and mounting position are covered in the role and selection of case pressure equalisation valves.
Hardware is the weakest link in sealing reliability. Hinges, latches and handles corrode and seize in damp conditions, so specify stainless steel or a properly plated finish. Structural options and corrosion treatments are described in toolbox hinges, latches and sealing structures.
Test references and packaging markings
Verification for a shearing machine case normally draws on three document families: transport packaging test standards, environmental test methods, and general machine tool specifications.
Transport packaging testing centres on the GB/T 4857 series. The drop test verifies corner and base impact resistance, the stacking test quantifies deformation under long-term storage and container stacking, and the vibration test exposes fastener loosening and liner abrasion. These are discussed in GB/T 4857 transport packaging testing and case design.
On machine specifications, GB/T 9061 (general specification for metal cutting machine tools) supplies the accuracy inspection and assembly datum approach; as a metal forming machine, a shear can reference GB/T 23281 (stamping) for related requirements; and cutting and blanking tolerances can reference ISO 9013. These citations establish the accuracy datum of the component in its assembled state; they are not used to qualify the case itself.
| Reference | Purpose for a shearing machine case | Typical agreed item |
|---|---|---|
| --- | --- | --- |
| GB/T 4857 series | Basic tests for transport packages | Drop height, stacking load, vibration spectrum |
| GB/T 4208 / IEC 60529 | Enclosure ingress protection | IP54 and IP67 classification and testing |
| GB/T 9061 | General specification for metal cutting machine tools | Accuracy inspection method, assembly datum |
| GB/T 23281 | Metal forming (stamping) requirements | Component accuracy and process tolerance |
| ISO 9013 | Thermal cutting quality and tolerances | Blanking tolerance reference |
| MIL-STD-810H | Environmental test methods (not a military certification) | Temperature, humidity and vibration methods |
One clarification is worth stating plainly: in this industry a MIL-STD-810H reference is a pointer to test methods only. It is not a military certification and does not represent military product qualification of any kind. Where a purchaser cites it in a technical agreement, the agreement should also name the method and procedure numbers — for vibration and shock in particular — because without those details a completed test cannot be judged pass or fail.
On marking, a shearing machine case should carry model, quantity, case mass, centre of gravity, no-invert, no-roll, keep-dry and case number. Cases containing blades should also carry a tilt indicator, which lets a receiving inspector see immediately whether an over-limit tip-over occurred in transit. Markings must use weather-resistant material; sea freight removes paper labels reliably.
Sizing by blade length and component mass
Shearing machine sizes span a wide range. A small machine uses blades about 1300 mm long weighing 15 to 25 kg each; a mid-size machine 2500 to 3200 mm at 40 to 80 kg; a large machine 4000 to 6000 mm at 120 to 200 kg. Hold-down assemblies and blade beams are heavier again, typically 200 to 800 kg.
| Component class | Typical length | Typical unit mass | Suggested case | Handling |
|---|---|---|---|---|
| --- | --- | --- | --- | --- |
| Small blades | Up to 1300 mm | 15–25 kg | Carry-length case | One person, two hands |
| Mid-size blades | 2500–3200 mm | 40–80 kg | Length case with side handles | Two-person lift |
| Large blades | 4000–6000 mm | 120–200 kg | Length pallet case | Forklift or crane |
| Hold-down assembly | Machine dependent | 80–300 kg | Mid-size pallet case | Forklift |
| Blade beam | Machine dependent | 200–800 kg | Heavy pallet case | Forklift, multi-point lifting |
| Accumulator and hydraulics | Machine dependent | 20–120 kg | Separate sealed case | Two-person lift or trolley |
For long cases, verify bending resistance as well as mass. A practical rule: beyond 3000 mm case length, either build the base with stiffening ribs or add two full-length steel reinforcing bars externally. Internal reinforcement alone is often insufficient, and a case that only has internal stiffening can still deflect at mid-span after a long sea voyage under stack load.
Returnable cases also need a service-life assessment. Repeated loading widens liner cavities and leaves permanent compression marks in the load-spreading layer. Methods for evaluating both case and liner life are set out in protective case service life and replacement interval.
Shearing machine cases are almost never standard products. Each project has to be built around blade length, the number of hold-down cylinders, whether the hydraulic parts travel separately, the transport route and the stacking height. For this sector the JUNZHIJIA brand, manufactured by Kexin New Materials (Guangdong) Co., Ltd., covers blade length cases, hold-down assembly cases and separately sealed hydraulic cases, made either to drawings or from sample parts, with cavities, dividers, latches and ingress rating combined as required. Goods are supplied wholesale, through distribution and direct to overseas buyers, while inspection and material documents can be provided under contract and branding is available for customers running their own OEM or ODM programme.
Frequently Asked Questions
Q: Which way should a shear blade face when it is packed?
A: Facing inward toward the cavity wall or facing upward are both preferable to facing down. With the edge up, nothing may rest on it and an edge sleeve must be fitted; with the edge inward, leave 3 to 5 mm of soft clearance at the cavity wall so the edge is not pressed against something hard. Edge down is the arrangement to avoid, because the full mass of the blade then passes through the edge into the case floor and any drop can chip it. Where space forces you to stack two blades, insert a full-length rigid separator between them and make sure the bearing area covers the entire blade length rather than resting on a few contact points. Mark the sleeve position with a coloured stripe so a missing or displaced sleeve is obvious at a glance, and keep one spare sleeve of each profile inside the case lid. A blade that has travelled without its sleeve should be examined along its full length in good light before fitting, because small chips are easy to miss in a dim workshop.
Q: Can blades and blade beds travel in the same case?
A: Yes, provided they are layered and the bed never sits on the blade. A bed is a heavy casting with hard edges, and placing it directly on a blade presses hollows into the cutting edge. Put the bed in the bottom layer on the load-spreading material with its bearing face upward, cover that face with 3 to 5 mm of medium-hardness rubber, add a rigid separator, and place the blade in its own pocket above the separator. Arranging the bed face-up also reduces the risk of its own bearing surface being scored. The separator must be one continuous sheet rather than several pieces, because a joint line concentrates load exactly where it is least wanted. Label the layers with a simple diagram inside the case lid, so that a technician repacking the set at the far end of the journey does not have to guess the intended order. Damage blamed on poor packaging turns out, on investigation, to have been caused by incorrect repacking on the return leg more often than anyone expects.
Q: What preparation does a hydraulic hold-down system need before packing?
A: Work through depressurise, limit and cushion. Depressurise by releasing system pressure completely and confirming the return line holds none. Limit by inserting equal-height blocking pads between the feet and the table so the feet cannot creep down inside the case. Cushion by adding a soft layer beneath the feet to absorb handling vibration. Skipping the limiting step is what damages the urethane pads: under residual pressure or self-weight the feet descend slowly and take a permanent hollow, and after reassembly the clamping force is uneven enough that sheet creeps during the cut. Pack each foot with the pad facing up in its own pocket, at least 30 mm clear of metal components. Leave a laminated card in the case recording the depressurisation step and the blocking pad positions, because hold-down protection is the step most often skipped when a machine is packed in a hurry at the end of an installation job. If the pads are missing on arrival, inspect the cylinder rods for bending before reassembly; a foot that has travelled a full stroke against a hard stop usually leaves a mark on the rod.
Q: How does a spring hold-down differ from a hydraulic one in transport protection?
A: The decisive difference is that the springs are already compressed when the machine is assembled, so any further compression in transit produces permanent set and changes clamping force directly. Spring-type protection therefore centres on relieving or limiting: relieve with a temporary fixture so the springs approach free length, or, where that is impractical, fit rigid limit sleeves at both ends to lock the compressed length at its assembled value. Hydraulic systems centre on releasing residual pressure and limiting stroke. The post-assembly checks differ too — hydraulic units are inspected for weeping and piston rod distortion, spring units for free length and consistency of clamping force across the beam. Whichever type is fitted, photograph the assembly after locking and before the case is closed; photographs are the cheapest evidence available in a later dispute about whether a component travelled in the correct state. For a first installation, arrange for the same technician to unpack and confirm, since knowledge of the locking method is easily lost between dispatch and commissioning.
Q: Must the accumulator always be discharged before packing?
A: Yes — this is a safety requirement rather than an option. A nitrogen accumulator stores energy while charged, and rising ambient temperature in transit raises nitrogen pressure further. If the case is also sealed, that combination can put unexpected thrust into the return circuit, and in extreme cases the piston rod extends on its own or the case distorts under load. Follow the machine manual to reduce nitrogen pressure to a safe value or discharge it completely before dispatch. If discharging is impossible at the site, the accumulator should not travel inside the case at all: treat it as a pressure vessel consignment with its own documentation and markings, and confirm separately whether it falls within dangerous goods classification. Where the beam and guideway ship as one heavy assembly, fit a hoist ring at each end rather than using slings around the beam, since a sling under load marks the guideway faces it passes over. Mark the hoist points on the outside of the case so the receiving crew can plan the lift without opening it.
Q: What corrosion protection actually works on blades for sea freight?
A: Use a three-tier combination of coating, wrapping and humidity control. Coat non-cutting faces with corrosion-inhibiting grease or oil. Wrap with vapour-phase corrosion inhibitor paper or film to create a local protective atmosphere. Add desiccant inside the case and keep the shell's moisture transmission rate low. Two rules govern the vapour-phase paper and are frequently broken: the distance from the wrapped surface to the paper should generally stay under 300 mm, and the wrap should be as sealed as practical, otherwise the inhibitor escapes before doing its work. For slender items such as blades, wrapping first and then seating the wrapped component in its cavity outperforms laying loose sheets alongside. Note the nitrogen pressure reading before and after discharge and leave the record inside the case. If the accumulator travels separately, keep its connecting hose with it rather than in the main case, so the two cannot be split in a warehouse and the assembly cannot be reinstalled without a new hose being sourced.
Q: Why does the blade gap adjustment need to be locked before packing?
A: Because these mechanisms use eccentric shafts, wedges or screws to set a gap measured in hundredths of a millimetre, and in the free state they respond readily to vibration. Random vibration lets the adjusting element creep, and the result after reassembly is a gap that differs between the two ends of the same blade pair, so one end of the sheet shows heavy burr while the other shows roll-over. Lock in two steps: set the screw or eccentric to its assembled position and secure it with nylon ties or a temporary clamp plate, then insert thin shims between the adjusting faces to raise friction so vibration does not reach the locking device directly. Every temporary item needs an oil- and heat-resistant removal tag. Photograph the locked mechanism before closing the case and note the removal sequence on the machine door. A technician who removes the ties without checking that sequence may release the adjustment while the beam is still restrained, which transfers load into the mechanism and changes the very gap it was meant to preserve.
Q: Is IP67 enough, or should the rating be higher?
A: For a shearing machine case, IP67 is normally sufficient for sea freight, provided humidity inside the case is also controlled. Sealing stops outside vapour entering; it does nothing about moisture already inside or about condensation driven by day-night temperature cycling, and that condensation is the main reason cast iron surfaces show rust spots. Fit a pressure equalisation valve as well so internal and external pressure can equalise slowly, since a large differential is what sucks a gasket open. Three questions set the requirement: could the case be rained on or washed down, does it contain uncoated carbon steel surfaces, and will more than two weeks pass between delivery and commissioning? Where the case is opened at intervals during a long project, plan the desiccant quantity around the number of openings rather than the shipping duration alone, and keep spare sachets in the lid pocket so the barrier can be restored immediately after each inspection. Moisture control fails gradually rather than suddenly, so the first sign is usually a light bloom on a machined surface, not a visible rust patch.
Q: What support spacing should be used under a blade?
A: Keep it under 500 mm, which is tighter than for general shaft-like components. A blade has a small cross-section and therefore a low section modulus, so an equal span produces considerably more deflection. For a 4000 mm blade, nine or more support points are advisable; for 2500 mm, six or more. A bearer strip of the same length as the blade, supported by evenly spaced blocks underneath, works better than placing the blade directly on separate blocks, because it removes the risk of a local high point marking the blade. Calculate the actual spacing from the blade's real section rather than copying a figure from another component type. For blades beyond four metres, check the support blocks with a straight edge before loading instead of trusting the machined flatness of the case base, because a base that has been dropped once can still look serviceable while no longer being flat. Mark each support position on the liner so that repacking at the far end follows the correct spacing.
Conclusion and further reading
The whole job of a shearing machine case reduces to one sentence: deliver the blade straightness, the hold-down resilience and the hydraulic cleanliness to site unchanged. Three actions decide whether that happens — blades flat in a single layer with full-length even support, hold-downs either depressurised or relieved according to type, and a case that solves restraint, corrosion protection and humidity control together rather than one at a time. Get those right and the overwhelming majority of transit disputes never arise.
When specifying, give the manufacturer the component list, the transport mode, the expected storage period and the acceptance criteria in one package and let them derive the liner architecture and case class. On export projects it is cheaper to settle the split-shipment plan while the machine is still being designed, so that the removability and protection requirements of blades, hold-down assemblies and accumulators are designed in from the start.
Further reading