Oh so that's where I am going wrong, no Lab coat!
I will add it to the shopping list.
Monday evening I successfully printed a B switch left blade front filing jig.
Martin, you are a magician! I don't know how you do it, but the holes lined up perfectly even though it is printed on the slant!
Tuesday, I left the printer producing a B switch right blade front filing jig and went to the cinema for an 11:30 viewing of "Wicked Little Letters". Thoroughly enjoyable....
Upon my return however, disaster had struck!
The printer was still trying to produce the filing jig, but had the nozzle had clogged and so there was about 3mm of invisible layers!
Of course I mean "missing" layers".
I immediately aborted, and investigated the cause.
There was some filament dust on the filament drive gear wheel and surrounds.
There was "caramelised" filament on the nozzle, and in the nozzle etc.
I believe a combination of the spool snagging in the rollers and the fact that I had obviously not adjusted the filament drive wheel tension correctly (if at all, I can't remember) had caused the problem.
After reviewing a Youtube video about nozzle changing, I found it quite easy to follow the instructions to disassemble the print head mechanism, and replaced the nozzle, as well as cleaned out the heater block and the filament feed tube(the aluminium finned item).
I replaced the nozzle rather than attempting to clean it, as the filament had become a hard brown enamel stuck to the outside & inside of the nozzle.
I cleaned up the filament drive wheel.
Having put it all back together again, I fed the filament in and this time made sure that I did adjust the tension before trying the print again.
I must say that it was all relatively simple to take apart & put back together again, much easier than changing the headlight bulb in my wife's Ford Fiesta!
The B switch right front blade filing jig came out perfectly yesterday evening
Today I have printed a 1:6 vee filing jig, and the printer is 91% of the way through a 1:6.5 vee filing jig.
These jigs are really good, thank you Martin.
Now I just need to use them properly, and also get down to actually designing a layout!
Steve