I have been having trouble with the automatic needle threader on my embroidery machine. It appeared that the little metal hook was too high for the eye of the needle, and so was slipping to one side or the other. I checked and re-checked that the needle was in as high as it would go.
Eventually it occurred to me that the problem had started when I started a new pack of needles (75/11 as opposed to my usual 90/14). I tried another needle from the new pack and the problem was just the same, but when I changed back to a needle from my previous pack there was no problem at all.
Has anyone else found this? Both packs of needles are Hemline ones. I have just ordered some Schmetz to replace them (my preferred brand, but not available locally).