Needles breaking on Singer 15-91

[lukeoliver1776]

Recently bought a 15-91 for sewing chrome tan leather for bags. I got everything tensioned as far as I know, and it was working great for awhile. I eventually felt confident enough to sew the side of a bag. And I suddenly started breaking needles. I was using size 18 leather point needles with tex 90 thread. I thought this may be the problem so I started using tex 70 with size 18 needles. Kept breaking needles. Eventually used some smaller needles because I ran out of size 18 needles and kept breaking needles. I know size 18 needles is kind of reaching the max this machine can sew, but It was having no trouble before. For context I am sewing together two pieces of 5-6 oz chrome tanned leather together. Recommendations or critique would be great. Thanks in advance.

[Constabulary]

Are you probably pushing the leather materials and the needle hits the needle plate? Have you tried sewing something else w/o braking needles? Have you checked the needle hook timing? Maybe the hook tip is hitting the needle and is breaking it.

[lukeoliver1776]

4 hours ago, Constabulary said:

Are you probably pushing the leather materials and the needle hits the needle plate? Have you tried sewing something else w/o braking needles? Have you checked the needle hook timing? Maybe the hook tip is hitting the needle and is breaking it.

I don't think I was pushing/pulling the leather through but its a possibility. I'm having trouble going slow because my machine just wants to go fast with a thicker material.

I was able to sew perfectly fine before doing a larger bag. This could rule out the needle hook timing?

You seem like you use a lot of Singers. Any experience with 50s models and do you recommend needle and thread size?

[kgg]

13 hours ago, lukeoliver1776 said:

Kept breaking needles.

Have you checked to see how much slop there is on the bobbin / hook shaft. If the needle is slightly delayed due trying to punch through too thick a material with too small a needle for the thread being used. Then combine those with any slop due to wear and tear of the machine then hook could be striking the needle or the needle could be hitting the bobbin case or if the needle is being buckled the needle probably will break.

Personally I think you are using the wrong class of machine and just asking to much from a domestic sewing machine. The Singer 15-91 was meant to sew Fabric not leather. Two layers of 5 to 6 oz for a total of 12 oz leather which is roughly about 1/4" thick ( https://www.leffler.com.au/leather-thickness-conversion-chart/ ).

You should read this article about what machine you need to sew leather consistently at that thickness.

kgg

 

[Wizcrafts]

14 hours ago, lukeoliver1776 said:

I was using size 18 leather point needles with tex 90 thread.

Tex 90 thread requires a #19 or #20 needle. Your #18 needles hold the thread too tight and poke a hole that is too small to pull the knots up inside the layers.  Thread Exchange sells Schmetz needles for your machine in #19, here. Try them and see if they work for you.

Put some grease on the gears inside the head where the motor output gear drives the guts. Don't put oil in the motor. If it has cups with lids, they are probably for special grease that is available in syringes. Otherwise, use sewing machine oil in every oil hole and connecting rod inside the front cover. Hopefully, this will loosen up the drive. If your foot controller is old, it may have lost resistance at the startup position. You can replace it with a modern solid state controller.

I am telling you all of this because I used to service and resell old Singer iron body machines. The 15-91 was a solid seller and I was able to sew 8-9 ounce bridle leather belting with #92 thread, using a #19 or 20 leather point needle. But, if the controller was worn, the motor lacked punching power. I have a page on one of my websites that is about the Singer 15-91. Maybe you'll find something there that helps you. It has manuals too.

[lukeoliver1776]

46 minutes ago, kgg said:

Have you checked to see how much slop there is on the bobbin / hook shaft. If the needle is slightly delayed due trying to punch through too thick a material with too small a needle for the thread being used. Then combine those with any slop due to wear and tear of the machine then hook could be striking the needle or the needle could be hitting the bobbin case or if the needle is being buckled the needle probably will break.

Personally I think you are using the wrong class of machine and just asking to much from a domestic sewing machine. The Singer 15-91 was meant to sew Fabric not leather. Two layers of 5 to 6 oz for a total of 12 oz leather which is roughly about 1/4" thick ( https://www.leffler.com.au/leather-thickness-conversion-chart/ ).

You should read this article about what machine you need to sew leather consistently at that thickness.

kgg

 

I haven't checked for slop in the bobbin/hook shaft. You may be right about the machine not being intended for my use, however, I did research and came to the conclusion that it should be able to sew up to 10oz leather easily. I'll take a look at the article and the slop in the bobbin/hook shaft. Thanks!

[lukeoliver1776]

29 minutes ago, Wizcrafts said:

Tex 90 thread requires a #19 or #20 needle. Your #18 needles hold the thread too tight and poke a hole that is too small to pull the knots up inside the layers.  Thread Exchange sells Schmetz needles for your machine in #19, here. Try them and see if they work for you.

Put some grease on the gears inside the head where the motor output gear drives the guts. Don't put oil in the motor. If it has cups with lids, they are probably for special grease that is available in syringes. Otherwise, use sewing machine oil in every oil hole and connecting rod inside the front cover. Hopefully, this will loosen up the drive. If your foot controller is old, it may have lost resistance at the startup position. You can replace it with a modern solid state controller.

I am telling you all of this because I used to service and resell old Singer iron body machines. The 15-91 was a solid seller and I was able to sew 8-9 ounce bridle leather belting with #92 thread, using a #19 or 20 leather point needle. But, if the controller was worn, the motor lacked punching power. I have a page on one of my websites that is about the Singer 15-91. Maybe you'll find something there that helps you. It has manuals too.

Great information! I'll definitely look in to the proper size needles. Thanks for the link.

I was told my machine was recently serviced before buying it but I will also grease/oil anywhere that needs it. I also recently bought a new foot pedal off amazon which seems to work fine. Would you recommend something else?

 

I appreciate all of this information. I am still under the impression that this machine should be fine for my uses, hopefully all of this will solve my issues. Thanks!

[Wizcrafts]

@lukeoliver1776

I spent a few minutes looking for leather point needles in size 120/19 and found some on Thread Exchange and on Amazon. I haven't looked on eBay yet and have to go to work soon. You're going to have to use a leather point needle for your project. A round point wont get it done without great difficulty.

One thing I didn't mention if foot pressure. Did you know that broken needles and kipped stitches can be caused by insufficient presser foot pressure? This is because the leather or other material can lift up with the ascending needle. This is always bad  and could be part of your problem. Crank down the foot pressure screw a couple of turns and try again. But, either get #19 needle or use #69 thread with the #18 you have on hand.

[lukeoliver1776]

4 minutes ago, Wizcrafts said:

@lukeoliver1776

I spent a few minutes looking for leather point needles in size 120/19 and found some on Thread Exchange and on Amazon. I haven't looked on eBay yet and have to go to work soon. You're going to have to use a leather point needle for your project. A round point wont get it done without great difficulty.

One thing I didn't mention if foot pressure. Did you know that broken needles and kipped stitches can be caused by insufficient presser foot pressure? This is because the leather or other material can lift up with the ascending needle. This is always bad  and could be part of your problem. Crank down the foot pressure screw a couple of turns and try again. But, either get #19 needle or use #69 thread with the #18 you have on hand.

Noted! Leather point needles in size 19 are best for the thread I'm using.

I had not considered the presser foot pressure. I'll look in to that as well. Thanks again

[Gymnast]

15 hours ago, lukeoliver1776 said:

And I suddenly started breaking needles. I was using size 18 leather point needles with tex 90 thread. I thought this may be the problem so I started using tex 70 with size 18 needles. Kept breaking needles. 

The sudden change could be, that the needle changed height by the needle is not sufficiently fastened or the fixing of the needle bar to the crank shaft is loose. So I recommend that you check the height of the needle bar. Have you got the service manual? The other thing to do is to remove the shuttle hook and clean this area for possible remains of thread. The shuttle hook always need good lubrication at its race. You need to use leather point needles as Wiz already wrote.

Edited November 4 by Gymnast