How to Inspect Forklift Forks and When to Replace Them

“Specialists at Criterion Equipment take a look at the importance of taking good care of fork attachments on forklift trucks and provide important advice on how to do so.

“The metal fork attachments used on forklifts may seem indestructible, but eventually they wear out, just like any other machine component. Failure to carry out frequent fork inspections can result in a snapped fork, or a dropped load, which is not only expensive, but also dangerous,” explains Heinrich Frederick, Pretoria Branch Manager: Criterion Equipment. “It is also important that operators never carry a load that exceeds the fork’s specific load capacity. The weight capacity of every fork attachment is indicated on the side of the fork shank/face – operators must be made aware of this.

Read more below to learn more about how to inspect forklift forks, which measuring tools you should be using and how to accurately use them.

  • Fork Thickness – Forks are constantly subjected to abrasion which can lead to reduced thickness of the fork blades. If the blades are not at the desired thickness, the fork attachment’s lifting capacity can be compromised.
  • Check blade and shank / face angle – If the shank / face and blade/heel angle exceed 93 degrees outwards and 87 degrees inwards, the fork must be replaced. Do not bend forks back into place or weld them back in place.
  • Inspect forks for surface cracks – Check the entire surface of each fork for cracks. The heel area and hook on welds are the most likely place for cracks to develop.
  • Ensure straightness of blade and shank / face – If the shank / face or the blade is bent, the fork can no longer be used.
  • Check fork tip – The fork tip thickness should be inspected. If fork tip is worn out and too thin, the fork must be replaced or re-machined. To re-machine a fork, the front tip is cut off in order to gain thickness. The tips should also be checked for bends. Should the fork toe have a bend, the fork should be replaced. *To prevent friction on the fork tips, make sure to lift the fork attachement when forklift is in use / driving around on site.
  • Check fork heel – The fork heel is usually one of the first components of the fork that wears out. Make sure that fork heel is the same thickness as the rest of the fork blade.
  • Check weight capacity of fork attachment – This is extremely important as you don’t want to exceed your fork’s load capacity as forks can potentially snap and cause damage to goods. Weight capacity is indicated on the side of the fork shank / face.
  • Check latches that attach fork to carriage – Each fork has a fork latch, with a fork pin. The pins ensure that the fork is secured safely on the carriage. This prevents the fork from moving around while driving the machine. The fork latches are the only components that are welded onto the fork.
  • Use the correct tools to measure thickness – The metal on a fork can become worn down and reduce in thickness as time goes by. This can lead to forks that are no longer able to handle their original load capacity. Just 10% wear reduces load capacity by 20%, at which point the forks must be replaced. You can measure your fork’s thickness by using a set of tools. Read more below.

In order to measure certain aspects of your fork and ensure that your fork adheres to certain standards, you will be required to use the correct tools in order to do so. There are 3 tools that you can use, namely;

  • Measuring card, which can be provided by Criterion Equipment, and is used to measure the thickness of the fork’s heel and shank / face.
  • Fork Caliper
  • Vernier Caliper

Photos (From left to right): Plastic card measurer, Fork caliper, Vernier caliper

  • Step 1:

Measure fork shank / face thickness:

Place the card on the side of the fork shank / face. Check markings indicated on the card. i.e Fork yield thickness = 4

 

Check fork type:

Whilst keeping your card flat on the side of the fork shank / face, determine the fork type by checking the markings indicated on the card. i.e Fork type = N40

  • Step 2:

Measure thickness of fork heel:

Move card from the shank / face to fork heel. Place the card over the fork heel (as illustrated in picture to the left).

Fork heel thickness should match fork type (identified in previous step) i.e N40.

If the fork heel has a thickness that allows the gap to slide over, the fork is worn-out and will have to be replaced. Should the gap on the card fit perfectly on the fork heel without slipping over, the fork attachment adheres to required measurements / standards.

This instrument is used to measure the fork thickness, angle of the fork bend and the latch space.

  • Step 1:

Measure latch space:

Identify class of the fork i.e Class 3. Use fork caliper according to class.

 

The edge of the caliper is placed below the latch. Don’t place in the middle where pin is located, as the caliper will slide in. The caliper should be positioned to the edge of the latch.

If the edge of the caliper slides in between the latch and the fork shank / face, the latch is worn-out. The caliper should fit as per illustrated image to the left.

Photo: Measuring thickness of fork shank / face.

Photo: Measuring the thickness of the fork heel.

  • Step 2:

Measure thickness of fork shank / face and heel: 

Fork shank / face and heel measurements should correspond.

Once caliper is used to measure fork shank / face thickness, move caliper over to the fork heel.

Should the caliper slip over the heel, after measuring fork shank / face, fork is worn-out and will need to be replaced.

  • Step 3: 

Measure angle of fork bend 

When using the instrument to inspect the fork angle, the instrument should be flushed to the fork shank / face and the fork heel at the bend of the fork. This is to ensure that no mistakes are made on measurements.

The bend of the fork should not exceed 93 degrees. If it exceeds 93-degrees, the fork is bent and should be replaced.

  • Step 1:

Measure thickness of the fork shank / face:

Place Vernier caliper over fork shank / face to determine thickness.

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  • Step 2:

Measure thickness of fork heel.

Fork shank / face thickness – 10% = desired heel thickness

 

Adjust Vernier caliper to the calculated amount and measure fork heel to see whether heel adheres to calculation. Should the Vernier caliper slip over the heal, the fork is worn-out and should be replaced. Should the caliper fit perfectly, the fork adheres to required standards.

 

Calculation Example:

Fork Shank / face measurement = 4.1 > 4.1 – 10% = 3.7 > 3.7 = desired fork heel thickness

Criterion Equipment would like to thank Heinrich Frederick, Branch Manager: Criterion Equipment Pretoria, for sharing these fork safety checks and tips. Heinrich Frederick, Branch Manager: Criterion Equipment Pretoria.012 379 6132

Now that you are aware of all the important checks to do on your fork attachment, make sure that your forks adhere to the required measurements and standards.Should you identify that your fork attachment might not be up to standard and is in need of replacing, don’t hesitate to contact Criterion Equipment.

Have any questions? Give us a call! www.criterion.co.za | 011 966 9700

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