Introduction: Last Comes First
The 'last' or 'forme' used for shoe making is arguably the most important part of any footwear, but is a part of the shoe never seen by the wearer. Lasts are used to manufacture almost every kind of footwear from sandals to riding boots. The last determines the size, style, toe-shape and heel height of the shoe. Even if you were to draw a shoe, you already denoting the last shape as soon as you sketch the toe shape. As a designer, the process of making a pattern cannot start in earnest before the shape of the last has been produced.
Historically, the process of last making has been a slow and painful one- a blank of wood is carved, rasped and sanded to create an exact shape, then this process repeated for the opposite foot. More recently 'repeating machines' have been used to trace the last shape and carve a new one.
Materials have changed through the years from wood such as hornbeam and beech to high density plastics, even to cast metals for heavy-duty factory operations.
As a shoemaker I make one off bespoke footwear, I tailor each last for the client and am then obliged to keep this last archived for them. This work is done by hand, requires a vast amount of labour, repeated processes and will often result in inconsistencies. I have been thinking for some time about how this process could use new manufacturing techniques to improve the accuracy and speed of last manufacture.
In this Instructable I will go through some of the methods that I have been experimenting with during my research.
Step 1: Last Design and Basic Alteration
As you can see from the first image, there are many different toe shapes you can choose from even within the 'round-toe' category of lasts. There are many infinite variations on a round, almond, triangular, square or pointed toe- that goes for all aspects of the last too.
Toe shape affects style but also the way the shoe will perform- for example boot lasts tend to have a larger volume toe box plus a taller profile around the ankle, whereas a dress shoe will often have a sleeker and more pointed profile.
A great place to start your journey as a last maker is probably to get hold of a second hand pair of lasts in your size and to start making adjustments to the toe shape using a rasp or grinding wheel. This is a part of the last which has most licence for alteration without affecting the fit too greatly. If you start adjusting the instep or arch support you may find you start affecting the comfort of the last.
This is how I began my first last- I turned a regular shoe last into a sandal last by making the toe shape very asymmetrical and also decreasing its depth.
Step 2: Digital Last Design
For this project, I will be using Autodesk Crispin Lastmaker software to help me produce my last. The software allows digital manipulation of the last shape plus you can input key measurements to it for a bespoke fit. There is also a range of basic last shapes to choose from and even last grading for when you design your own shoe range!
There are websites that offer downloads of digital last files also, such as:
I have not used this service so cannot vouch for them.
Step 3: Export Your File
I have exported my file from Crispin as an .STL. I recommend you put the file into Meshmixer or ReMake so that you can check for holes or defects in the model. Once you have done this and the model is solid, you can send it directly to a 3D printer to become sliced and ready to print. In this case I have sent the model to print on a Fortus 450mc printer.
Step 4: First Print!
This is the first 3D printed last that I have made. I printed it in Polycarbonate plastic (PC-10) on a Fortus 450Mc printer. The interior support pattern was the double dense arrangement and used 16.91 cubic inches of print material plus 1.75 of support. I printed the right foot only as a test.
I tested my pattern (see my other Instructable https://www.instructables.com/id/Testing-a-Shoe-Pat... by making an upper and lasting it over. When I tried it on I found that although the length and girth were OK, the toe profile was too narrow for my foot.
Step 5: Paper Printing
Having tried the Fortus plastic print and getting an undesirable result of the last shape, I decided to explore other means of printing before committing to spending more money on plastic filament.
Mcor Indsutries make a printer which works by glueing sheets of A4 copy paper together and cutting them with a knife, layer by layer. This is quite a novel approach to printing as it is basic in so many ways yet also quite complex. The advantage is that it utilises readily available resources- paper and glue and produces a print that is completely solid at a fraction of the cost of FDM techniques.
The disadvantages are that like any paper printer, it is prone to jamming. The paper has a tendency to start peeling up at the corners and then causing the machine to jam. Of 6 prints (and counting) I did not get it to produce one 100% finished print before having an error! Luckily I did get one about 95% complete which was enough to extract a usable last from.
Due to the size of the build plate (210mm x 297mm) I was unable to make my last in one piece (size12) so split the model and nested the pieces. I then joined them together with masking tape.
The result was great- the paper is densely glued together and tough- like a soft wood. The density is also very helpful for attaching shoe soles as you have a dense object to strike against.
Step 6: Printing a Pair
Due to the high cost involved with print materials on the Fortus (and because the volume of a size 12 last is high), I decided to experiment using a sparse single internal density for the print in ASA plastic.
I made a test pair of shoes using the lasts and they were OK to handle during the lasting process, if a little light weight. As you can see in this video time-lapse I managed to make a full pair of shoes on the lasts without too much difficulty (time-lapse video courtesy of Instructables legend Scott McIndoe aka makendo)
The problem with the lasts is when I came to attach the soles on to the uppers. The process involves a great deal of hammering, over several stages of the process. The impact to the last can be seen very clearly in the photos. The plastic has cracked and de-laminated after just one pair.
After this happened I tried to fill the lasts with a combination of garnet and epoxy resin. Unfortunately this quick fix ended up as a sandy sticky mess! I had other suggestions like filling them with expanding foam but I feel that it becomes to messy and inconvenient, plus would not give a nice heavy and dense last, which is desirable.
Step 7: Solid Polycarbonate Lasts
After spending time in Crispin Lastmaker refining the toe shape of the last into a sleeker shape, I went back and forth to the 3D printer several times before biting the bullet and printing in solid PC-10 material.
The reason for the dithering was the outrageous cost of printing two solid size 12 lasts. I won't go into specifics but it was high! However, my rationale for starting the 30+ hour print was that they would LAST forever, so if I just make a pair a month for the rest of my life...
As soon as I collected them from the Fortus, I knew I had made a good choice. The weight was perfect and they are a thing of beauty in themselves!
Now I can go on and use these for multiple shoe projects for years to come.
chengXX made it!