Need help with Singer 1425..
 

I have my mother’s Siner 1425 and love how it pushes through thick seams. However, I am uncertain if it should sound so loud and like...grinding....while sewing. The manual says nothing about greasing the motor???? Can anyone help me understand this machine? Thanks!

You never grease the motor, leave the motor alone. You should clean and oil the machine..

https://www.vintagesingerparts.com/p...ing-gummed-oil

That is a little newer than what some of us have. The link donna13350 gave seems to be for the older vintage machines.

Does the manual mention anything about "Maintenance"? Cleaning dust bunnies from the machine might help. Also sometimes lint gets impacted in feed dog and bobbin areas that need to be cleaned out. Sometimes it could be a thread gets caught somewhere it doesn't belong.

Oiling plastic gears and parts generally is not recommended. If you can get inside to see if there are metal parts that rub together those can be oiled with sewing machine oil.

Janey - Neat people never make the exciting discoveries I do.