Be careful...I just looked up the Singer 15 on that list that tells you to insert the needle with the flat side to the right and thread it from left to right. I don't know if it's model specific, the needle on my 15-91 and 15-86 gets inserted with the flat side pointing to the left and gets threaded from right to left through the eye of the needle. I just checked the manual to make sure I remembered correctly.