Originally Posted by
Mickey2
Is that a replacement part? These models were so tried and tested, there should in theory be no reason for alterations like this. 401s usually behave well, but often in desparate need of thorough cleaning and oiling.
I know, this is what's making me crazy about it. In theory it should work just fine. But there are a couple of others who have had this exact problem.
All the parts were initially original to the machine, and it was cleaned and completely retimed, checking all the parameters including hook timing, gaps and thread clearances, etc. It just kept happening despite my swapping multiple variables.
Sure works perfectly now
