The development of the modern last
An investigation into how production of the last – an essential footwear tool – has seen a number of drastic changes in recent decades.
For several hundred years – if not longer – the foot-shaped last has been an essential tool of the shoemaker’s trade. According to the Oxford Dictionary of English, the word ‘last’ is derived from the Old English ‘læste’, meaning ‘to follow’.
Today, we are used to seeing a pair of lasts, closely resembling a left and right foot. However, as late as the 1850s, most shoes were made on absolutely straight lasts, with no recognisable difference between the two shoes. Generally, two widths were available for each size. A basic last was used to produce what was termed a ‘slim’ shoe and, when it was necessary to make a ‘fat’ or ‘stout’ shoe, the shoemaker placed a pad of leather over the cone of the last in order to create the additional room that was needed. Breaking in a new pair of shoes must have been far from easy.
In times past, typical shoemaking lasts were often made from beech, maple or some other type of hardwood, with the lastmaker using a long knife and bench. There were a number of criteria that the lastmaker would have to consider when selecting a particular piece of wood. These would include: i) a wood that could be cut cleanly, ii) one that was free from knots, iii) a wood that was not liable to split – a particular problem when carving a shape and driving in pins and rivets, iv) an example that had a hard texture to avoid excessive denting while keeping defined edges during the lifetime of the last, v) a wood that was close grained to create a last which would take a high polish, and vi) a wood that was not excessively hygroscopic (that is, water absorbing).
While no individual type of wood satisfies all these characteristics, careful selection and proper treatment of the last led to a satisfactory product.
During the 19th century, as part of the ongoing industrial revolution, cast iron lasts became the norm in Europe. Like hardwoods, cast iron was chosen because it retained its shape, even when in contact with wet leather and subjected to the mechanical stresses experienced when stretching and shaping the materials needed to produce shoes.
Back to wood – for a time
As World War I started to use up significant amounts of metal, many shoemakers turned back to using wooden lasts. This was often maple, sourced from Canadian forests that in many cases were owned by the last manufacturers themselves. Copy lathes allowed lasts to be produced rapidly following the creation of a correctly sized original model.
There was no significant further change in the way lasts were made until the Second World War, when the first commercial plastics started to be made. Following the end of the war, brittle thermoplastics were used to make lasts until the early 1960s. At that time, polyethylene was used for the first time. This proved to be a durable and tough material, which allows for many tacks to be driven in before needing repair. Later, injection moulding speeded up the process, with a roughly shaped block being turned down to an accurate last. Between 50 per cent and 60 per cent of the material was cut away during this process, but this was reusable. While bespoke hand-made wooden lasts may still be used by manufacturers of high-end footwear, most companies around the world use high-density plastic lasts.
At the beginning of the 20th century, cast iron lasts were made in a number of sections which were then often fixed together with interlocking pins. This allowed for the last to be taken apart in order to remove it from the partly finished footwear without causing too much damage. Wooden lasts also were designed to be broken down, with removable ‘scoop blocks’ held in place by screws or brass springs. Today, plastic lasts are normally hinged to allow removal after the shoemaking process, although in some regions, lasts are often made of solid polyethylene to speed up the process.
Machinery takes hold
During the early 1900s, last-duplicating machines were developed that could produce lasts faster than lastmakers could by using traditional methods. These new machines could make more than 1,000 lasts per day, compared with the very small number that a man could make in a day. Such a large quantity of lasts was needed because in the early part of the 20th century, a last may have remained in an individual shoe being manufactured for three to six months.
Although such automation was a great stride in the mass production of footwear, these machines still relied on a lastmaker to shape the initial last when it was ordered from the shoe designer before copying could start. This first last was called a ‘pattern’ or ‘model’.
Modern manufacturing methods
Computer-aided design (CAD) was introduced into shoemaking as early as the 1970s. It was then primarily used for grading rather than design purposes. CAD evolved into a design tool used in the development of lasts, as well as for footwear itself. There were a number of factors that encouraged this move, including the availability of more powerful hardware (such as digitisers) at affordable prices, major improvements in graphics capabilities and interconnectivity and the introduction of more user-friendly software with lower skill requirements.
The introduction of CAD enabled semi-skilled operatives to construct three-dimensional (3D) last forms from a library of last shapes – obtained originally by digitally scanning real lasts – and to engineer or manipulate the last section on a computer screen rather than working with a physical object.
The ability to blend toe shapes, foreparts and backparts with different heel heights on a CAD system, and to do this rapidly, was an advantage over more traditional hand-modelling methods. The alignment between the bottom plane and the upper surface of the last could be adjusted, as could toe spring and back height.
Once the 3D form was constructed and the correct last curvatures achieved, the data was used in the development of upper patterns, bottom components and other tooling. Modules were also available to compare different lasts, to analyse deviations and perform shape analysis. Having defined the last shape, this could be graded and the data passed to a numerically controlled (NC) last-machining system.
Today, companies with significant footwear runs generally use computerisation in some form when producing lasts. Some companies use computerised digitising, as previously described. This allows for a model last to be scanned so that it can be reproduced accurately on the screen and manipulated in digital form. Data stored in a program can be used to cut accurate lasts quickly, with modern machinery allowing a number of different sizes to be formed at the same time. Other manufacturers use the fully computer-driven route – designing the model totally on screen before it is cut out of a plastic block, without the need of a physical last needing to be shaped by hand. Either way, the model produced is then sent to the copy lathe operator, who produces as many lasts as are required.
Undoubtedly, digitised last data is being used to control all stages of last production leading to greater accuracy in turning and finishing of the final last, and reduce the need for further processing. A great benefit is that the design and manufacturing processes can be undertaken in different parts of the world. For example, last design may be undertaken in the USA, but the data files can be emailed to China for production there – close to the manufacturing plant.
Things have come a long way since the simple straight last was used by shoemakers the world over. Lastmaking was once a craft needing the trained skills of a foundry worker and a carpenter. Nowadays, it requires knowledge of programming and CAD-CAM systems to produce a suitable basis for a pair of shoes or boots. Nevertheless, the humble last – however it is made – will continue to prove essential to shoemakers for the foreseeable future.
SATRA’s Digital Last Assessment service
Digital Last Assessment can help to identify mislabelled sizing and poor fit characteristics at an early stage, expediate design and production and decrease development costs.
This evaluation is a process in which the likely fit characteristics of footwear made on a last can be predicted. The volume created for the wearer’s foot within any item of footwear is predominantly determined by the shape and size of the last on which it is manufactured. Other variables also play a role in the final fit of the product, including the construction method of the footwear, the upper and soling materials and the style of footwear and fastening systems. Predominantly, however, it is the last that forms the characteristics of the final shoe.
SATRA's Digital Last Assessment service is a simple, fast and cost-effective way of measuring and analysing the shape and dimensions of 3D CAD files of men’s, women’s and children’s shoemaking lasts.
SATRA offers four digital last assessment tiers in order to help to determine fit characteristics and appropriate size marking during the digital design stage. Fixing possible problems during digital design will prove to be vastly cheaper than finding mistakes later in the physical design and manufacturing process. A 3D file of the last can be sent to SATRA and precise measurements taken, to be compared to either the well-established SATRA guidelines or, alternatively, to a retailer’s or manufacturer’s guidelines.
The four tiers
Tier 1 – Verification through accurate measurements over several key dimensions to confirm they are as expected. Tier 2 – Assessment of these key dimensions against SATRA's own recommendations for improving fit at the marked size. Tier 3 – Forecasting the likely population coverage offered by the last, based on conclusions from SATRA's Global Foot Dimensions report, and guidance on how this can be maximised. Tier 4 – Adjustment of the last based on SATRA recommendations to improve population coverage while retaining the aesthetic and general shape of the original design.
The cost of this service, per last, is: Tier 1 GBP100; Tiers 1 and 2 GBP180; Tiers 1 to 3 GBP350; Tiers 1 to 4 GBP850. In addition, SATRA recognises that not every organisation has digital last models available. This is not a barrier to utilising this new service, as physical lasts can be shipped to SATRA to be scanned and digitised in STL format for GBP100 per last.
How can we help?
Please contact SATRA’s innovation and development team (firstname.lastname@example.org) for help with Digital Last Assessment.email@example.com
This article was originally published on page 10 of the December 2021 issue of SATRA Bulletin.