When I use the machine which is about 20 years old the needle goes up and down but I have to pull the material through quite firmly or the stitches just bunch up. I've cleaned and oiled everything but to no avail

Jane, February 2015

had the same problem, i just adjusted the foot tensioner on top to place more pressure to help the dogs to grab the material better,
also remember that on the left of the bobbin upper left of bobbin, there is a dog lowering switch which lowers the dog foot from grabbing the material make sure, using this switch that the dogs are in the up position

vassili9876, February 2015