I recently purchased a Singer 16-188 and 1300-1 industrial sewing machines from an estate sale. The owner had an upholstery business and had passed away.  I got both machines, one table with a clutch motor and a lot of parts that don’t necessarily go to either machine.  I have just under $300 in the purchase and felt that it was worth the money.  
I wanted to use them for light leather work and both seem to sew pretty well.  The 16-188 has a walking foot and the other a straight sewing machine.  The problem that I am having is the 1300-1 was balling up on the bottom side.  (I am mainly turning this one by hand). I tightened the upper tension and made sure the needle was completely up and locked then is started working a lot better.  Tonight when I tried it, it started balling up again.  
On the 16-188 I changed the needle (it was a little shorter) and it wouldn’t pick up the tread and was just poking holes.  I put another one, different size and it was doing the same thing.  I found one in the treasures that was the same length but was a little bigger and it started out ok then started getting caught somewhere and it was fraying the thread at the needle eye.  That is when I decided to give it up this evening.   
This is the first machine that I have used and have been hand stitching for over a year now.  I was thinking for the money this might speed things up and give me more options. Not sure where to go from here.  Maybe I have two expensive boat anchors.  Any advice would be very appreciated no matter how much it hurts.  
Thank you