Originally Posted by
Mickey2
In addition I would mention to match needle size and thread weight (thickness) correctly. Since you are hemming jeans you might be using top stitch thread, I suggest upping the the neede size to 18 (110) right away.
Double check for needle insterted correct way, if it's not it will mess up the stitching. Loops under the fabrics generally means you need to tighten the upper tensioner; loops on top means you need to loosen upper tensioner.
That said, you might have to set bobbin tension for the thread you use, but often you can get by with adjusting upper tension to get a balanced stitch.
If the machine is new to you, remember to cleand and oil it, take off faceplate, throad plate, round plate in the back, bobbin case clean out any dust and lint you might find. Detect all oil points and give them a drop or two.
Thank you so much. Such a breath of fresh air getting these replies so fast. I've pretty much been on my own with my 15-91 since I purchased it off ebay. Initially when I got my 15-91 it powered up, but the needle would not move. This Singer was an estate find, and then my find on eBay. I had it shipped to my door all for 120.00 and I thought I did pretty good. It came with everything original, with the Singer electric foot pedal, and nothing looked to need rewiring. I knew so little I actually thought the motor was bad, but come to find it was just the whole machine was parched everywhere.
I ordered up some vintage Singer oil and Motor Lubricant, and tried my best to put the oil in all the little holes and, yes, I did download a singer manual and gave it a once over skim to see how to lube it up. Basically, I got it going again with just oil. The way I applied the motor lubricant is questionable.
I found the two oversized screws and removed them to access the cylindrical ports where the motor lube is to go in. I clumsily squished about a 1/4 tube of the motor lube in each port, but I don't see how it's supposed to lubricate anything or go anywhere. The motor lube is like a vasoline consistency, but I figured whatever, I followed the instructions and I used the right stuff so far as I know. I removed the wheel (pardon my not being hip with the sewing machine lingo) and used my finger to lube up the gear teeth under it. I removed the face plate near the light bulb and the one near the needle and used oil in there. It's running pretty good.
The sewing I did was on a pair of polyester work pants, using some pretty simple black thread, nothing heavy. I had trouble really seeing if my bobbin tension was right. I saw a video where a lady shows letting the bobbin dangle, and if it plum drops really fast the tension is too loose, and if you bounce it a couple times and it doesn't let any thread out, then you are too tight. I couldn't do this test, because the darn bobbin kept falling out of the bobbin casing, so I sort of winged that part.
I'm pretty sure I had the top tension at about 7 or 8 while I was sewing the pants and it did ok. I wanted to do more practice, so I grabbed a pot holder and stuffed that under the pressure foot and gave it a go. That's when I started getting a mess on the bottom stitch. It was like the stitches either tangled up on me, or the stitch on the bottom was loose, and way longer than the top stitches. I haven't a clue how to adjust the tension right for thicker material. I also have not a clue as to what thread thickness vs. tension vs. needle I should be using. I will definitely take advice and look into those write ups you spoke of. My ultimate goals is to be able to stitch shoe uppers together with this machine. So, we're talking moderately thick leather material, which isn't as thick as I've witnessed the machine handle. Anything thick I'll be sewing by hand. I'm not trying to abuse the machine, and then have a motor go up on me.