And here is the correct tool. Life if so easy when you have the right equipment. With this tool snapping the O-rings in place was a matter of seconds work. So do your self a favor and get one of these. Velleman is quite clear by the way in the manual as well about the tools you need, so go check this before you start your build and get frustrated. OK enough about the tools lets continue with the build.
After the this you need to construct the other carriage and these two go together with some rods. It is very important that you get this very straight for a smooth movement later on. So you are advised to tighten all the screws while moving the carriage so that it aligns during screwing. Don't apply too much force since it will twist the part then. I found also that adding a little teflon spray helped to make thing evens more smooth.
After this you have to install the first motor. In total there will be 4 motors in the whole printer. One for the X, Y and Z movement and one for the extruder later on. The most difficult part in this step is cutting the timing belt. You have to count an exact number of tooth and not more one or less. If you screw up here you can order a spare part :) I think I recounted about 5 times before I finally cut it and still wasn't sure :)
Here is the complete X/Y carriage including the motor and the belt. Eventually the heated print bed will be attached on top of this whole construction. Well so far I am happy with the result. I'm not that skillful in mechanics but it all runs very smoothly. Before I called it a day I did read the rest of the manual to estimate how far I could get the next day. But I was pretty sure it was going to take at least 3 days to build this thing. So far for day 1. To be continued..