Because the present hot end seems to be clogged and I can't get it open with all the tricks that I saw on the internet. Already replaced the thermistor but that doesn't seem to help. Can I get also a new grubwheel at the same time? Where can I get this?
See Extrusion head dead, RIP Materia 101? above as he contacted Sharebot and they had spares in stock for his heater end, and I suppose that they may have the grub wheel assembly also. Too bad that Arduino has not seen fit to offer spares as they have touted the machine this past year as an everymans printer. I suspose that the logistics of providing a printer kit is just too difficult. Take a look at the affordable printer being touted by https://store.newmatter.com//#!/ it is suppose to be a 399 US printer that was funded by "CrowdSource"