Andy Cap submitted this idea :
I'm no expert, but the lower spool should be readily removable - held by a
couple of clips or something - so it is easy to change colours etc.
I don't think it should require a screw to be removed ! It' suggests to me
that it may not quite be in the right position, which *may* explain why the
lower thread is not always being caught. Apart from that, it sounds as if
you're doing everything about right.

The lower spool does come straight out, the large screw head is
directly below the spool and I fancy serves as the centre for the
rotation - I was simply trying to add to the description in the hopes
someone might recognise it and the problem.

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Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk