Chain Wear Gauge

The FB chain wear gauge has been primarily designed for the measurement of leaf chain or forklift chain wear.

It can also be used to accurately measure all chain with an imperial pitch ranging from 3/8" to 3".

When conducting chain inspections it is recommended to observe the requirements of:

• The Lifting Operations and Lifting Equipment Regulations (LOLER) 1998
• The Provision & Safe Use of Work Equipment Regulations (PUWER) 1998
• The FLTA Technical Bulletin 02
• The BITA Guidance Notes GN15 and GN28

Competent persons carrying out safety inspections should also meet the requirements of BS EN45004:1995.

The following features are considered absolutely necessary for the correct measurement of chain:

• The chain gauge must be accurate
• Results must be consistent and repeatable
• The results must be clear and not require calculation
• The chain gauge should be easy to use 
• Measurement results should be easily demonstrated to end users
• The instrument must be robust and professional

All high-quality chain is manufactured to consistently tight tolerances.

Chain is deemed to be worn beyond its safe service life when the nominal pitch length has been extended by 2% to 3%. At this point the fatigue life of the chain is reduced and the ultimate breaking strength is considerably lower.

A chain that is elongated by 2% is becoming dangerous and the competent person must determine a safe time limit for replacement.

A chain that is elongated by 3% must be renewed immediately. Until the chain is renewed the equipment to which it is fitted must not be used.

It is recommended that wherever possible the chain should be cleaned and measured in situ with the chains placed under load.

The recommended load equates to approximately 1% of the minimum breaking load of the chain.

Without the availability of a set of check weights it is, for the purpose of putting the chain under load, normally sufficient to allow the chains to be tensioned by the weight of the carriage and forks.

1) Close gauge to confirm calibration

The FB chain wear gauge has been precision manufactured and accurately toleranced.

The manufacturing process includes calibration referenced back to National Calibration Standards with each unit undergoing thorough final inspection.

While the instrument cannot be adjusted for calibration, it can be checked by simply closing the slide fully and reading from the 'Percentage Wear' window the accuracy to tolerance.

In the unlikely event that the instrument moves out of calibration into the ± zones it will be as a result of wear to the moving components and should not, therefore, be used other than as a guide.

Similarly, if the 'V' jaws are damaged, the instrument may not perform accurately.

2) Identify the pitch

The nominal pitch of the chain must be measured over the pin centres of one of the OUTER link plates.

To assist in this the instrument is provided with three separate pairs of red arrows.

Utilise one of the pairs located on the edges and the centre of the gauge. Depending upon ease of access to the chain one pair will be more suitable than the others.

Locate the arrows over the pin centres of the chosen outer link plate and the nominal pitch of the chain will appear in the 'Pitch' window on one side of the instrument or the other.

Select and use the correct side of the gauge relevant to the measured nominal pitch as follows:

Once the pitch has been determined the number of pins (n) that the chain wear is to be measured over will appear in the adjacent 'Measure over Pins' window.

3) Measure the chain

Identify the section of chain that regularly runs over the pulley as this part of the chain is the most susceptible to wear. Measurements must then be made in at least three separate locations on this section.

With the chain under load and using the correct scale, place one 'V' jaw of the instrument over the first pin (pin number 1) of the selected section and then extend the slide until the other 'V' jaw locates over the pin (as previously determined).

The percentage of wear will appear in the box at 0.25% (¼%) increments

Whilst viewing the 'Percentage Wear' window, ignore any readings in the 'Pitch' and 'Measure over Pins' windows.

If the instrument shows a 2% or greater elongation, the red indicator will completely fill the window. This is a warning that the chain requires replacing.

A judgement must be made, by the competent person, as to the likelihood of the elongation reaching 3% before the next thorough examination. The competent person must also  specify a safe time limit to ensure renewal of the chain prior to the elongation reaching 3%.

The chain wear gauge will show wear up to 4%. Any chain used for lifting with a measured elongation of 3% or more is dangerous and must be renewed immediately.

Until the chain is renewed the equipment to which it is fitted must not be used.

Care of your FB Chain Wear Gauge

• The instrument should be kept free of oil and grease
• It should be wiped clean after use and stored in the case provided
• Do not leave the gauge where it may be exposed to high temperatures

Through our work on British Industrial Truck Association (BITA) technical and ISO standards committees we’ve always been aware of chain safety and the implications of chain wear.

For many years we’d stocked a plastic chain wear gauge which we gave away as a free product to customers. However, it quickly became clear that this flimsy plastic device wasn't fit for purpose.

We decided that if we were going to continue to supply a chain wear measuring instrument, we wanted it to be a tool that every engineer would want to have in their toolbox.

The gauge needed to be accurate and to be able to give a reading of precise percentage elongation. But it also needed to be simple to use.

With that in mind, we started to develop the idea of a device that measured elongation over a specific number of rivet pins as determined by the pitch of the chain.

Operating in a similar fashion to a vernier slide rule, the aim was to create a device that measured the actual length of the chain, that made a comparison to the chain’s nominal pitch length and that calculated the percentage of chain wear.

We produced the first prototypes using cardboard, Blue Peter style. With a few modifications to the design, we came up with a device that not only calculated the wear but also measured it.

A little more work added the ability to measure the chain pitch and a calibration window so you could check the gauge was in tolerance. What was unique about the device was its ability to measure elongation accurately and with confidence.

The FB Chain Professional Chain Wear Gauge is now the industry standard.

It is used extensively by maintenance engineers and insurance inspectors who appreciate the importance of being able to precisely recognise the amount of chain wear in a safety-critical lifting chain.

The FB chain wear gauge was designed to specifically address the common problems previously associated with the ‘Tape/Steel Rule’ methods.

Having studied all the other versions that were available in the market we’d noted that several of these, sold and distributed by major OEMs, used measured lengths of between 12” - 15”.

When measuring chain, a compromise needs to be made in determining the length of chain to be measured. Too long a length and there will be a danger of diluting the true extent of the wear, while too short a length will require far greater measuring accuracy than is generally available out in the field.

There is strong evidence that it is rarely possible to accurately find the centre line by other ‘visual’ methods.

With this in mind, the FB ‘Professional Chain Wear Gauge’ incorporates “V”-jaws for positive pin location and removing the necessity for estimating the position of the pin centre line.

The FB chain gauge has a window which gives a direct reading of chain wear. This eliminates any need for calculation and removes any confusion or possible error associated with an arithmetical calculation.

FB Chain and HSE were closely involved in the drafting of the BITA guidance note GN15 and FB, therefore, has no hesitation in recommending that "Competent Persons" should follow all the guidelines contained within it.

The FB Professional Chain Wear Gauge is an instrument designed to fully assist the “Competent Person” by ensuring complete compliance with the GN15 process.

What makes the FB Chain Wear Gauge a better option than tape or steel rule?

Accuracy

• While a tape or steel rule requires visual line up and a totally steady hand, the FB chain gauge incorporates “V”-jaws that always locate on the centre of the relevant pin to ensure accurate measurement.

• The percentage elongation is directly shown in the “Percentage wear” window to ensure complete clarity of the results.

Consistency and repeatability

• The positive location of the “V”-jaws used on the FB chain gauge means that the results can be checked and repeated with ease.

Ease of use

• Every FB chain gauge is supplied with full and comprehensive instructions that describe the process of measurement in detail and give clear guidance on the correct process to be followed.  
• With the ease of use of the chain gauge, and the positive location on the pin ends, it is equally effective whether in the hands of a skilled engineer or a complete novice.