jcm55.. I would check the wiring coming from the lightbulb..perhaps the wiring is old and brittle. The bulbs in older machines get pretty hot..but the bulb should last a LONG time. Most local fabric stores have a person who does repairs, etc...and if the machine is sewing well..it may be worth it to take it in and have the wiring replaced. If this is the problem, I would also have the repair person check the wiring to the wall plug and also to the foot pedal. These older machines may not be up to the electrical standards of today..and you certainly don't want to risk a fire. New sewing machines are not made like they used to be...so the cost to upgrade the wiring is really an investment.
What a kind husband you are! taking the time to help get your wife's machine in running order..I'm sure she really appreciates all of your effort!
I hope this has helped...
Woodsy

What a great vintage machine for your wife to sew on! My mom's 15-91 (c. 1950) came home to live with me a couple of months ago. This is the same machine I learned to sew on when I was 12 years old. The cabinet is in great shape and I had the machine tuned up and it's running well. You should perhaps have the wiring checked - the bulb should last longer than that. Or maybe try a new bulb one more time in case it was just a lousy bulb?

The Needlebar web site is wonderful for learning about vintage machines. Just don't ask them how much it is worth - ha!

Teresa

Here is a link that might be useful: The Needlebar

Hello, I was wonder if you would be able to help. I have a 15-91, I got everything set up to start sewing, but then as I used it on a test piece it would only lay a couple of stiches and then it would'nt hook on to the bobbins thread, and then just curl up the fabric, I am just learning to sew and dont really know what to check. Thank for any help

Okay--double check your needle. The flat side of the shank should be to the left and the needle threads from the right to the left.

Annie

Thank you so much Annie, you were right the needle was in the wrong position

It happens all the time, especially when a new machine comes in. I've been sewing for nearly 40 years now and still put a needle in wrong once in a while!

Annie

I am having problems with getting my recently purchased 15-91 sewing thick materials. The machines is slow to start piercing the thicker materials, so I increase the speed/power then the machine takes off at high speed. Is there anything that can be done or did I buy the wrong machine???

A 15-91 1948... Comes with everything originally sold with.
Even owners manual and singer buttonholder mint condition.
What is good asking price???

Anyone else have a problem with the bobbin on the 15-91 Singer. It does not seem to be holding in the case and is not functioning properly. Any hints would help.

Are you sure you are using the correct bobbin for this machine? When you put the bobbin in the bobbin case, can you get it to hold (before you insert it into the machine)? I'm having trouble visualizing your problem - it's not a common complaint.

Can you anyone help me? my grandmother gave me her 15-91 Queen table style sewing machine and I'm having trouble with the bobbin, I believe i have the machine threaded correctly and bobbin is set up correct, when I start sewing the bobbin get's all knotted up and turns in to a mess. What am I doing wrong?