3.5 Jacking, Skidding, Rollers & Moving Equipment

Sub-task B-7.03 (Selects hoisting/lifting and moving equipment) and B-8.02 (Performs hoist/lift and move) cover far more than cranes. Most heavy machinery inside a plant is moved without a crane — jacked, cribbed, rolled and skidded into place. This is core millwright work and it kills people who take shortcuts.

Jacks

Jacking Rules

1. Set the jack on a solid, level base — a steel plate or a hardwood pad spreading the load onto the floor. A jack sinking into fill or a floor drain tips and shoots out.
2. Centre the load on the saddle and make sure the lifting point on the machine is a designed jacking point capable of the load.
3. Jack the load in small increments and crib as you go. The rule is simple and absolute: the cribbing follows the load up, and the load is never left on the jack alone.
4. Never place any part of your body under a load supported only by jacks. Hydraulic jacks bleed down, seals fail and hoses burst.
5. Lower in small increments too, removing cribbing progressively — most jacking incidents happen on the way down.
6. Use two or more jacks in a coordinated sequence for a long machine, keeping the load level so it does not walk off a jack.
7. Inspect for leaking seals, bent rams, damaged saddles and illegible capacity markings and remove defective jacks from service.

Cribbing and Blocking

              BOX CRIB                               Rules of thumb
                                          - Use sound, square, hardwood or
          ===============                   engineered cribbing (no split,
          ||           ||                   painted or rotten timber)
     =====================               - Each layer laid 90 degrees to the
     ||                 ||                 one below, with full corner bearing
     =====================               - Height limited to roughly 3x the
     ||                 ||                 narrowest base dimension
   =========================             - Keep the crib plumb and centred
        solid level floor                 - Wedges and shims only for final
                                            take-up, never as main support

Cribbing capacity depends on the wood species, timber size and the contact area at the corners — a crib carries load only where the timbers actually cross. Never build a crib on soft or uneven ground without a sill, and never mix timber sizes within a layer.

Rollers, Skates and Skidding

Roller rules:

• Distribute the rollers so the load stays within the roller footprint at all times, and account for the centre of gravity shifting as the load tips over a floor joint or transition plate.
• Keep the centre of gravity low and the load secured to the skates so it cannot walk off.
• Never put hands or feet near a roller. Feed and adjust pipe rollers with a bar, never by hand.
• Watch the floor rating and surface: expansion joints, floor drains, trench covers, and slab edges will stop or capsize a roller move.
• Use tag lines for control and keep everyone out of the potential travel path — especially downhill of the load.

Pulling and Positioning Devices

Always confirm the anchor point is rated for the load. Attaching a come-along to a handrail, a small pipe, or an unknown lug is a common and serious error.

Forklifts and Industrial Trucks

Powered lift trucks are designed, tested and used in Canada under the CSA B335 series, and operators must be trained and evaluated.

Rated capacity is quoted at a standard load centre — commonly 600 mm (24 in) from the face of the forks. As the actual load centre moves further out, the safe capacity drops steeply.

Worked example. A truck rated 2,500 kg at a 600 mm load centre picks up a gearbox whose centre of gravity is 900 mm from the fork face. The overturning moment is proportional to the distance, so the approximate available capacity is:

$2{,}500 \times \frac{600}{900} = 1{,}667\text{ kg}$

Always confirm against the actual data plate and load chart on the machine, and re-check the plate whenever an attachment is fitted — a fork extension, drum clamp or side-shifter reduces capacity and moves the load centre.

Stability: a counterbalanced lift truck is stable while the combined centre of gravity stays inside the stability triangle formed by the two front wheels and the pivot of the steer axle. It is why raising a load while travelling, turning with a raised load, or braking hard causes tip-overs.

Operating rules: travel with the forks low and tilted back; travel in reverse when the load blocks the view; sound the horn at blind corners; never lift personnel on the forks or on a pallet — only in an approved, secured personnel platform with the truck's controls attended; and set the mast vertical, lower the forks, apply the brake and remove the key when parking.