Search for a timber, Application or Project
Quick Links
Informative

What is finger jointed timber?

10 minutes
March 7th, 2023

Finger jointed timber is a type of wood process made by joining pieces of wood together to form a longer piece or large volume of a desired length. The pieces are cut at an angle, creating finger-like projections that interlock with each other. The joints are then glued to create a solid, seamless pieces of wood.

This process allows for the efficient use of different lengths and enables the creation of longer, stronger and more stable options that can be used for a variety of applications, such as mass timber, benchtops, furniture, cabinetry, cladding and flooring.

Many companies utilise short lengths when finger jointing, resulting in many joints to make the full length. Others use longer lengths, resulting in fewer joints and, depending on the final length produced, many pieces without a joint at all.

Australian Sustainable Hardwoods (ASH) has decades of experience finger jointing timber to create products for the Australian market. Beginning with structural timber, the ASH manufacturing plant expanded over the years to join sustainable architectural timber into products like benchtops, staircase components, joinery and mass timber solutions.

How finger jointed timber is beneficial from a manufacturing perspective

  1. Efficient use of wood: by using smaller pieces of wood or offcuts and joining them together, the overall yield from each log can be increased, leading to lower material costs and reduced waste. Based on the efficient processes at ASH, manufacturers and furniture makers can save over 30% in waste using the finger jointed lengths rather than docking solid random length packs.
  2. Consistent quality: by using small pieces of wood, manufacturers can choose high quality pieces for the jointed product, which leads to a more consistent and higher quality final product.
  3. Longer lengths: the finger jointing process enables the creation of longer pieces of wood, making it possible to produce longer furniture pieces and other products that would otherwise be limited by the length of a single piece of wood.
  4. A large volume of set lengths for an architectural requirement: such as thousands of pieces as a desired hard-to-source set length (4.8m, for example)

How finger jointed timber is beneficial from a design perspective

  1. Increased stability: the jointed pieces create a solid and stable structure, allowing for the creation of furniture and other products that are strong and durable.
  2. Versatility: the ability to use smaller pieces of wood to create longer pieces makes it possible to produce products with unique and intricate designs, and with fewer joins in ASH’s product, designers and architects are provided with an aesthetically pleasing, appearance option.
  3. Environmentally friendly: by using smaller pieces of wood or offcuts, manufacturers like ASH can reduce the overall amount of waste generated, making finger jointed timber a more environmentally responsible choice compared to solid wood products. For example, a set length requirement of 3.6m might require a tradesperson purchase 3.6-5.4m lengths and dock back to 3.6m. The offcut may become waste. Finger jointing allows that same in-feed stock to be used only the offcut becomes the first piece in the new finger jointed section
Finger jointed battens and dressed boards in Lucy Liu, Melbourne.

What is a horizontal finger joint?

A horizontal finger joint is a type of finger joint in which the fingers are cut along the edge of the piece, rather than the face. In this type of joint, the fingers of two pieces of wood interlock with each other horizontally to form a solid and stable connection. The joint is then glued to create a seamless piece of timber with a butt-joint appearance on the face.


Small and discrete horizontal finger join in this ASH staircase stringer.

What is vertical finger joint?

A vertical finger joint is a type of finger joint in which the fingers are cut vertically along the face of the piece, rather than the edge. In this type of joint, the fingers of two pieces of wood interlock with each other vertically to form a solid and stable connection. The joint is then glued to create a seamless piece of wood.

What is finger jointed timber used for?

At ASH, finger jointed timber is an option for many applications including mass timber, furniture and joinery, benchtops, staircase components, set length lining and internal and external battens. Unlike many imported products there are very few joins with ASH products, as feed stock used to create set length is all random lengths.

Set length finger jointed H3 treated battens.

How are finger joints tested?

Timber finger joints can be tested for strength and quality through various methods, including:

  • Tensile strength testing (Modulus of Rupture): this measures the maximum load a finger joint can withstand before breaking.
  • Compression testing: this measures the amount of force a finger joint can withstand when compressed.
  • Shear testing: this measures the amount of force a finger joint can withstand when subjected to shearing forces.
  • Bending testing: this measures the amount of force a finger joint can withstand when subjected to bending forces.
  • Visual inspection: this involves examining the joint for signs of defects, such as cracking, splitting, or gaps in the joint.
Glacial OAK (ASH’s brand of American Oak) finger jointed battens.

 

At ASH, we conduct all testing methods listed above either directly through finger joint testing in isolation or through finished lamination testing. All finger joints are third-party assessed as per AS5068- Finger Joints in structural products.

“FJ MOR (Modulus of Rupture) testing indicates a finger joint can be structurally stronger than full wood fibre” – Nathan Wellins, ASH Laminating Manager.

How finger jointed timber will play a significant role in the future of the built environment

  • Sustainability: the ability to use smaller, offcut pieces of wood and/or reduce waste makes finger jointed timber a more sustainable choice, especially as the demand for environmentally responsible products increases.
  • Increased efficiency: the finger jointing process is efficient and cost-effective, making it possible to produce longer and stronger pieces of wood while using less raw material.
  • Improved strength and stability: the finger jointing process results in a solid and stable structure, making it possible to produce high-quality products that are stronger and more durable. An example of this is ASH’s MASSLAM range of mass timber solutions that can replace concrete and steel in commercial and large domestic buildings.
  • Cost-effectiveness: the use of smaller pieces of wood and increased efficiency in the manufacturing process makes finger jointed timber a cost-effective option compared to solid wood products.
  • Increase scope of species: some timber species, such as Glacial Oak (ASH’s brand of American Oak), are not grown to lengths needed for some applications (ie – 5.1m straight flight stair stringers). Finger jointing in a seamless and attractive manner maintains the visual intent of that timber species while preparing it for a use it would have been excluded from.

Overall, finger jointed timber provides a cost-effective and versatile option for both manufacturers and designers. If you are considering utilising finger jointed options like Glacial Oak for long stringers, contact us.

Contact us for finger jointed options