Set Construction Techniques: Joints

Joints:

For this part of the ‘Scenic Construction For The Stage,’ I am going to be exploring potential joining methods for a number of materials, which can be used within set construction.

The Butt Joint:

butt-joint

(Butt joint, 2016)

This technique is where two pieces of materials are simply joined by ‘butting’ them together. It is the simplest joint to make as all it is, is cutting two pieces of material, such as hardboard, to the appropriate length and then butting them together. It is the simplest joint, however it is the most weakest. Because the material being used to butt is only the end grain and long grain this results in the joint being relatively weak.

The Dowelled Joint:

dowell

(maxwel and profile, 2008)

The dowelled joint, more commonly known as dowelled butt joint. This has been a common way of reinforcing butt joints. They are mainly used in frame and carcass construction. Dowel joints are mainly popular in chairs, cabinets, panels and tabletops. They may also be used to help with the alignment during a ‘glue up.’

The technique consists of cutting the material to size followed by drilling a number of holes in the joint surface. The holes are generally made by a dowelling jig, which helps with accurate hole placement. Accuracy is vital in this joint, as the material needs to be lined up perfectly to ensure that the holes are together. After successfully doing this, you then will put short dowels in the holes which were previously drilled. They would be inserted with glue. The joint would then be brought together and held together and clamped until the glue had fully dried. After all of this has been completed, it would have produced a joint which is much stronger than the butt joint without any reinforcement. The dowels provide strength even after the glue has deteriorated.  

Over a period of time, the dowels will eventually shrink and become loose. Loose dowels will then allow the joint to flex, although it may not fall apart. When rocking chairs start creaking or bookcases start wobbling, this is a sign that the dowels are loosening. With this reason alone, dowelled joints are not suitable for high quality furniture. For the full use of this joint, it is more suited to making frames, shelving and for alignment.

The Mitre Joint:

mitre

(Craftsmanspace, 2016)

The Mitre joint is simple to construct like the butt joint. Although it is rather similar to the butt joint, this one is stronger and has much greater aesthetics. This joint is much stronger and more appealing because the ends are cut at a 45° angle and then glued together. This creates a better surface area for when you apply adhesive. It also conceals the end grain giving it a flush look. For the best results of cutting this angle, is by using a drop saw instead of a hand saw. This will create straight and neat edges. This type of joint is common with picture frames as there is no end grain showing and don’t require much holding strength.

The technique used for making a Mitre joint, is by firstly drawing a 45° angle line on the material, which in this case could be either timber or mdf. After this, you would cut the material will a drop saw. When this has been completed, you must check that the angles are accurate. If this is correct then the next step would be to join the joint together with an adhesive and leave it to dry. If the joint is not accurate, then the angles will not fit together.

The halving joint:

halving

(Reserved, 2016)

A halving joint is a woodworking joint where two materials are joined together by removing some of the material from each piece so that they will overlap. The halved joint is differentiated from the lap point (technique.) The material will then be joined at the edge rather than on the flat.

The halved joint is created by cutting a slot on the opposite edges of the material to be joined so that they slip together. The amount of material removed is equal to half of the material being joined.

This joint is rather weak and prone to splitting which is due to the lack of shoulders which would have prevented twisting.

The Dovetail Joint:

dovetail

(2016, 2002)

A Dovetail is a joint technique which is most commonly used in woodwork such as furniture, cabinets and traditional timber frames. It is known for its resistance to being pulled apart, therefore it is an excellent joint for the sides of a drawer.

A series of pins are cut so that it can reach the other end and interlock with tails, which are cut to the other end of a board. The pins and tails have a trapezoidal shape which looks like this image on the right. Once it has been glued together, a wooden dovetail joint doesn’t require fasteners.

The way the tails and pins are shaped make the joint difficult to pull apart, and impossible to do so, after the adhesive has been applied and dried. It is a rather difficult joint to make and a lot of practise is vital. There is a number of dovetail joints, and when it is cut accurately they are impressive and attractive. The joint is especially strong when it is used with a good adhesive, such as PVA or cascamite. The slope angle varies according to the type of material you are using. For softwood, the slope is 1:6, hardwood is 1:8 and if you are not sure, you can compromise this with a 1:7.   

This joint is known to have pre-dated written history. One of the earliest ways this joint has been used, which has been recorded, is dating back to the Egyptian era as they were used in furniture entombed with mummies. In Europe, this joint is known as a swallow-tail joint and/or fantail joint.

Referencing:

Butt joint (2016) in Wikipedia. Available at: http://en.wikipedia.org/wiki/Butt_joint (Accessed: 28 September 2013).

maxwel and profile, V. my complete (2008) Dowel joint. Available at: http://galbraithbook.blogspot.co.uk/2009/03/dowel-joint.html (Accessed: 28 September 2013)

Craftsmanspace (2016) Free plans, patterns, books.. Available at: http://www.craftsmanspace.com (Accessed: 28 September 2016)

Reserved, A.R. (2016) DIY do it yourself how to information and advice. Available at: http://www.diydoctor.org.uk (Accessed: 28 September 2013)

2016 (2002) A design and technology site. Available at: http://www.technologystudent.com (Accessed: 28 September 2013)