Singer 15-91 thread injector. anyone have experience with these?

[eviscerate3]

Thank you guys for the links. i am hoping to get a chance tonight to read thru it pretty thoroughly. Looks like it will be a fun project. Do you have any tips on where to start? Or any problems that you ran into while working on yours? i appreciate the help! thank you.

[Mouseskowitz]

I'm fixing up a model 99 right now. It was initially pretty seized up. After a couple days of good oilings it was smooth as can be. The other thing you can do is use isopropal (sp?) to dissolve some of the old oil first. Try not get it on the exterior of the machine and let it dry for a day before oiling. Also give it a through cleaning, especially by the bobbin.

[gmcttr]

..Do you have any tips on where to start?...

See my reply in "Show Us Your Thread Injector"... https://www.hammockforums.net/forum/...&postcount=679

[bulb]

I would start with, will the motor spin freely, if it does, check all wiring connections corrosion and/or tightness. If it still just, hums, I would take the motor out and clean the commutator and brushes.

[gmcttr]

While the motors usually do benefit from having the commutator and brushes cleaned, typically, the motors just hum or strain because the oil throughout the machine has turned to varnish locking everything up or there is a thread lock in the bobbin/hook area. This can be checked by releasing the bobbin winding clutch so the motor is disconnected from the rest of the machine.

[NJTroutstalker]

I tried in vain to repair my grandmother's 1938 model 1591 and could not find anyone to repair the electrical cord and motor. Many of the older models have a direct drive pot motor that is no longer made and is impossible to find in working order. I took mine to 3 different repair shops and they all said the same thing- ditch it and buy another machine! None of them even wanted to buy it off me so I figured they were telling me the truth. My research revealed that almost all of these older machines had wiring problems. I would go to a couple of sewing machine repair shops and tell them what you are thinking about buying and get their advise first before buying the one you are looking at. Hope this helps- not trying to be negative but if I could have salvaged my grandmother's machine I would have been willing to pay someone to fix it. Good luck to you!

Did you take it to a sewing machine shop or an electric motor shop? I've had motors rebuilt and rewound. Those guys can fix most anything.

[eviscerate3]

Well, so far I have cleaned the entire exterior of the machine and have taken off the motor assembly to check the wiring. I noticed one of the caps for the brushes was broken at the head of it. I am thinking of heating a screwdriver and melting in a new notch, letting that cool and then try to remove it. Any thoughts? The other brush is in bad shape too. The spring is disconnected from the brush itself. I have the commutator out and am going to go ahead and clean it while its out. The wiring looks pretty good with no cracks in the insulation or anything. Still very pliable. Do you think i should replace it anyway while it is apart? The grease inside looks very old. What do you all find is the best way to remove all of it so I can start with fresh grease? Also I took the knee switch apart to check the contacts on the inside and it seems I could just use it as a foot switch without any modifications. Any opinions on that? I am used to a foot switch and the knee idea doesnt seem that appealing if not necessary.

So far this is the list of replacement parts I see that I need.
Bobbin Winder Tire Ring
Carbon brush caps (2)
Spool pin felt pads
Carbon Motor brush (2)


Are there other parts, springs etc. that typically go bad? I am hoping to order everything at once so I can get it running sooner than later.

I appreciate your help!

[eviscerate3]

I have a bunch of pictures but am at work now and cant post them yet. I will get them up later today. Thanks!

[Mouseskowitz]

Take a look at the sites gmcttr has posted in the past. There is a good one that talks about the rebuild and grease. I haven't done this yet personally, but from the reading I've done it sounds like you're on the right track.

[VictoriaGuy]

Well, so far I have cleaned the entire exterior of the machine and have taken off the motor assembly to check the wiring. I noticed one of the caps for the brushes was broken at the head of it. I am thinking of heating a screwdriver and melting in a new notch, letting that cool and then try to remove it. Any thoughts?

I don't know how well Bakelite melts; we're a bit 'spoiled' nowadays with thermoplastic parts that respond to tricks like that.
Just be very careful not to mess up the threads on the housing aka brush holder.
A dremel can be useful for jobs like this. Drilling a couple of holes and using pin pliers is another approach I've used once.

Also I took the knee switch apart to check the contacts on the inside and it seems I could just use it as a foot switch without any modifications. Any opinions on that? I am used to a foot switch and the knee idea doesn't seem that appealing if not necessary.

Most of the knee controls I've seen on US machines were just the foot control slipped into a holder with the knee lever, like yours.
You might be surprised how quickly you adjust to the knee control when you are sewing. I had the same reservations about using the knee control (built-in to the machine) on an Elna, but it only took a few minutes to get used to it. (It's not the knee, but more the thigh on those controls; I think 'thigh control' would have been too 'risque' to mention in the 1950s??. )

It definitely beats chasing the little foot control across the floor.