Hiding thread ends
The thread ends can be hidden inside the cord. You only need a needle. I mostly use blunt embroidery needles, for thick yarn knitting finishing needles. Try to choose a needle where the eye just fits the thread, using a thick needle can make finishing difficult.
The books say that you can hide the end inside the cord. I have never managed to do this. Instead I sew the end around the loops of the cord in some kind of an overcast stitch. I do this for a few centimeters and then cut the end near the cord. This way the end of the cord becomes slightly thicker, but usually it is not a problem.
I filmed a small video of hiding an end. On the video I use extra thick yarn, but the principle is the same with thinner yarn.
Cutting a lucet cord
It is always better to make a cord into the given measurement. If you need 3 x 1.5 meters of cord, make three pieces of 1.5 meters instead of one 5 meter one. If you cut a lucet cord, it will start unraveling and the end must be finished with a generous dollop of glue or by a thread wrap or with a knot.
There is another way, although it is not suitable for very fine cords: you can actually terminate a cord a bit below the cutting line. This can be done to both sides of the cut edge. You will need a few safety pins or openable knitting stitch markers and a darning needle or a thin knitting needle or a thick pin. If you are aiming at a certain length, cut 5-10 cm above that spot. E.g. if you need the finished cord to be 1 meter long, cut at 1.05-1.10 meters.
First you cut the cord. Go on, bravely put scissors on it.
Then start working on one of the cut ends. If you are aiming at a certain length, mark the point of the final length with a safety pin. Now, with the help of the needle etc. carefully try to get loose bits of yarn out of the cord. After that you should have two loops and a yarn end, just like in a cord under construction, just in minisize.
Now you can pull the yarn end to unravel the cord for a little bit (if cutting to measure, to the mark). Now place the cord on the table into the same position as the luceting start position: left loop a bit higher up, right loop a bit lower and the yarn above right loop. Now place a safety pin in the right loop, this stops it from escaping in the next step.
Gently pull the left loop to make it bigger. Try to take the extra from the yarn end and not from the right loop.
When the left loop is a few centimeters (or an inch) long, place a safety pin/stitch marker on the loop.
Now gently pull the right loop to make it a bit bigger.
Remove the right safety pin and put the thread through the right loop, just like when finishing the cord normally. You can tighten the loop by pulling the left loop.
Now take off the left safety pin/stitch marker and put the yarn end through the left loop and pull the yarn.
The cord is now finished and won't unravel. If you wish, you can hide the ends as usual.
I made a small video of cutting and finishing (warning: loading it may take a bit of time). On the video I use thick yarn, but I have done the same process with pearl cotton nr 5, that is quite thin. It is just a bit fiddlier, but doable.
You should always aim at having enough yarn for the full length of the cord (see FAQ). Switching yarn is possible, but the spot where you switch will always be a bit thicker than the rest of the cord.
A neat switching can be achieved by running the new yarn inside the cord for a bit, then switching and running the old yarn inside the cord for a bit. This same technique allows you to make a multicolored cord with color blocks. The ends are cut near the cord and then the cord is pulled gently and that hides the ends inside the cord.
Note that this technique only works with basic lucet where the yarn goes round and round the lucet and never between the horns. In the picture below the white line shows the route the yarn takes.
In the beginning you braid with the original. Then a second yarn is added on top of the cord and the yarn from the ball is put on top of it.
Continue with the original yarn while putting the second yarn always behind the lucet (this assuming you do luceting with turn technique).
I made a little video on working with these two yarns. You continue this for a bit so that the new yarn is securely inside the cord. Then switch yarns, the originally active yarn (here white) goes inside the cord and the new yarn (here pink) starts making cord.
If you just wanted to switch to a new yarn because the original ran out, let the original yarn travel inside the cord for a bit and then cut the yarn right at the cord. When you pull the cord carefully on either side of the cut point, the end disappears inside the cord.
If you want a striped cord, you can keep the passive yarn inside the cord and switch yarns at appropriate intervals. If you want to really exact, you can count the stitches you make in each color.
If you need to switch yarns in a cord that will be pulled very hard, you get a sturdied switch point by running both yarns together for a few rounds. However, that makes a lot thicker spot on the cord than the above method.
The secret of the flat cord is in the manner the running thread is looped around the horn. The yarn is crossed and the yarn from the ball must be under the yarn from the cord. If you accidentally do it the easy way and the yarn from the ball is on top, you do not get a flat braid. Because the yarn from the ball stays on the same side of the lucet all the time, I make this cord with a no-turn technique.
I made a few little videos: In the first one I make flat cord with my giant lucet and jumbo yarn. That hopefully makes it easier to see how the yarn is looped on the horn. In the second one I make cord my way, with the yarn in the right hand. With this technique I can get up the speed, although not to the same level as with standard lucet.
The flat cord is slightly different on different sides. With thin yarn the difference isn't that noticeable, but with the jumbo yarn it is easy to see (click the pic if you want to see a bigger version):
Here front and back with thinner yarn (knitting cotton):