Friday, 19 March 2010

Nice Threads

One place left on the London course, which is great. We usually fill up in the last few months, but there has been a run this year. Probably the change from 3 to 2 weeks; seems to be more manageable for people.
We are preparing for New York, making lists; checking supplies; making packs for students. We have booked our flights and I am getting excited. It will be May before we know it.

Now then, threads. Essential to a strong construction. They must be sturdy and water resistant. Many people use ready-made threads, which are fine. I prefer to use hemp cords which I twist into threads. The main advantage to this is that you can make them to the length you want and also the thickness. For a welt you need 5 cords of the hemp. For the sole, you need 3. You can also use linen which is thinner, so you need 5 and 8 cords respectively. The other big advantage is that the wax we use heats up and melts when you pull the thread. When it sets again, it forms a plug which acts like glue, holding the thread in place. Particularly good on the soles. Have you seen how the threads show through the channel of the sole edge when the shoes are worn? Well the wax plug stops the sole coming off.
The other main element of the thread is the wax you use to coat it and make it waterproof. This you can make yourself using beeswax and either tar or colophony. But that is another post I think.


The first thing to think about when making your thread is the length you want. Most makers make 1 thread for each job, so to welt a pair of shoes you make 2 shorter threads. I prefer to make 1 longer one to do 2 welts in one. This has the disadvantage of taking longer to pull the threads through, but the advantage of only having to make 1 thread.
For 2 welts on an average sized mans shoe, I use 3 arms lengths of hemp cord.

The second thing to remember is that you need to attach a bristle to each end of the thread and to do this you need a thin tapered end because if you try to attach a full 5 cord thickness thread to a bristle which has to pass through a thin hole with another bristle coming the other way, then you will fail miserably.
So you need to break the cord each time in the following way. Hold with one hand and then roll forward down your leg with the other looking closely at the cord. You need to untwist it until all the fibres are in line and untwisted. At this point, the cord will break in a long beautiful taper.




You need to break each end in this way. With the second cord, hold the first and the second together and pull through till you get to the other end. The second cord needs to be about 1-2cm longer than the first with a tapered end.
Do a third cord.



Cord 4 and 5 are the same except that the taper must be longer, about 6-8cm. You end up with 5 cords like the picture below.



Next, you need to twist the thread. You will need a hook in a wall. Place the thread over the hook and then stand away till the 2 tapered ends are even. Put one leg up on a chair. Hold one thread in your mouth and then, holding the other in your left hand, roll it away from you down your leg with your right hand. Quickly grab it, making sure you don't lose the twist you have just imparted to it and repeat the twisting procedure. The twist will pass along the thread. Enough is judged like this. Move towards the hook. The thread relaxes and if it twists up on itself, you have done too much. This will cause problems when you are welting.
Now swap the ends and do the same thing. Now you have a fully twisted thread.




Now you are ready to put on the wax. Be sure not to let go of the thread, as the twist will unravel and you will have to start again.
Holding both ends with your left hand with your little finger holding them slightly apart, rub the wax along the thread on the top and then on the bottom so that all surfaces are covered.




With a good covering of wax, you must now burnish it. This heats the wax up so that it penetrates the middle of the thread, making it more durable and less prone to rotting.
You do this with a piece of scrap upper leather which you fold over the threads and rub a up and down in short fast movements. You will see it go glossy.




The last thing is to put a light coating of beeswax to help lubricate the threads. Not too much though.




You must protect the 2 ends with your life. They are easily damaged, but essential, so be careful.




Bristles. Originally they were hogs bristles from the neck of a boar, long and strong. They are hard to get and sometimes break. So I use nylon bristles. You can buy them from Algeos, or you can use fishing line (10 - 15 lb). The advantage of bristles over needles is that they are flexible, so that when they meet going in opposite directions through a hole, they neatly move past each other. Needles can just hit and get stuck. Also you can curve the end to match your awl.




You will have seen a little bit of sand paper in my box. The bristles are smooth and you need to key the surface so that the threads don't slide off when in use. To do this, gently rub the bristles with the very fine sand paper (above 220 grit). Only do about 2 thirds of the bristle.



You are now ready to attach the bristle to the thread. We will do that next week folks. It seems quite tricky, but it's ok once you get the hang of it.

Until then, happy shoemaking.