Fork inspection and repair

Fork Inspection

Why inspection?
Forks are safety items. The value of daily transported goods runs into billions. Therefore, highest attention should be paid to a regular inspection of forks.

Inspection periods:
Tests should be carried out on a regular basis. The international standard ISO 5057 provides for inspection at least every 12 months. Depending on the application, e.g. multi-shift operation or hard working conditions, test intervals should be reduced accordingly. Furthermore, drivers or operators of lift-trucks are responsible for carrying out regular visible inspections.

Who inspects / repairs?
The yearly inspection shall be carried out carefully only by trained personnel. This service is mainly provided by acknowledged forklift service companies. Only the manufacturer of the fork arm or an expert of equal competence shall decide whether and how a fork may be repaired.

Please observe:
An inspection, repair or exchange of forks shall only be carried out by pair. Very often, both forks are defective resp. the second fork has a big risk of having the same damage.

The use of safe forks, which are in perfect condition, is not only your duty but also an advantage. Working safety means working at lower costs! Ensuring safety at all times prevents disturbance and guarantees that your equipment is always at your disposal.

For an explicit definition of the fork we recommend to note down the fork stamping on the inspection protocol.

Inspection protocol

1. Wear

Fork wear

Extract from ISO 5057:

„If 10 % of the original fork thickness is worn, the fork has to be taken out of service.“ 10 % wear of the fork thickness already means a reduction of fork capacity by 20 %.

Basis for wear measuring is the original nominal thickness (n) of the fork (f.ex. nominal thickness (n) = 40 mm -> wear limit = 36 mm).
Worn forks must not be welded.

Attention: If fork blade thickness is differing to fork back thickness, please observe wear limit Smin (stamped in this case).

2. Cracks

Fork cracks

Critical areas:

  • Inner heel section
  • Welding seems

Testing methods:

  • Magnetic particle inspection
  • Penetrant flaw detection

3. Height difference of forks

Height difference forks

Height difference of fork tips should not exceed 1.5% of the length of fork blade (L).

Acceptable: h max. = L*/66
Level fork: h = L*/66 to L*/33
Replace fork: h > L*/33

(*L = Blade length in mm)

4. Permanent deflection

Deflection forks

Deflection of fork blade:

Acceptable: k max. = L*/66
Level fork: k = L*/66 to L*/33
Replace fork: k > L*/33

(*L = blade length in mm)

5. Angularity

Inspektion Winkligkeit

Forks are delivered with an angle of 90°. Forks with an differing angle need to be levelled or replaced.

Attention: For special applications, forks need to have another angle. Please check before inspection.

6. Locking devices

Inspektion Arretierungen

Locking devices precent unintentional slipping off the fork carrier. It is not allowed to use fork with defective locking devices.

7. Damage / wear of fork tip

Inspektion Beschädigung Spitze

As soon as the fork tip is worn, the fork needs to be shortened or replaced!

8. Lateral bending of the fork hook

Bending forks

Lateral forces and long-term use may cause lateral bending of fork hook. In this case, fork hooks need to be replaced.