Singer for sure....
Hey Guy,
Your machine is kinda a rare find. They were semi-popular around Michigan and elsewhere when new, but IMHO the Twin-Fan design was NEVER designed to be commercial machine. Because of this forced life, many died an early death from too much dirt being sucked into the cooling fans and coating the motor in schmutz. This of course overheated and killed many of them early on. Yours that you found DOES have a motor protector, but even this couldn't fix a overlooked design flaw that killed many a Twin Fan machine Singer or Kenmore, household model and Commercial alike.
It definitely hails from the early 80's as it still has the multi toned bag, with the plastic front that was like a leatherette which the wording is on, but also no longer had the lower dump hatch that the earlier styles had. They stopped the lower dump hatch in like 1981 or so. To Explain this better, Singer created a very unique bag, that had another chrome, or black plastic clamp-slide along the bottom like the one at the top. This allowed you to dump out the bag contents without removing the bag from the machine. When Sears found that most people used the inner paper bag, and not the cloth one, this was discontinued. IT was either that, or they did it to reduce costs.
Regardless, you do not see to many of these anymore,especially in that condition. I would in a heartbeat go and get that at least to preserve it from the dump, or it's final life as a grungy basement vac or worse.
You may need a new belt, and the bristles may be worn, but in that condition I wouldn't worry that this is too much a problem. I understand that those bags that it takes are NLA, as are the brush rollers, but you can use a Hoover type C bag in it's place.
You may find someone on here that may have access to some opld bags, and possibly a NOS, or even a lightly used rollerbrsh if need be.
If you do get it, If I were you definitely take of the hood and use another vacuum to remove all the lint and dirt accumulation from the innards. You should be able to find a Twin Fan belt at most Sears stores. In a pinch I've found that a Oreck belt will actually work well, along with a Hoover Elite belt. the Oreck is rather wide, but the Elite belt is kinda long. So you have to take the good and take the bad.
An F& G bag will not suffice like it does in the residential models because of another quirky bag design. Behind that plastic or leatherette face, is a built in dirt tube that goes up to a top mounted bag neck that actually points downwards. Like an upside down F&G bag neck. The stock bag had a short tube pointing upwards that the spring on the neck grabbed onto, and the bag filled from the top similar , but unlike the F& G style.
I believe it was Singer Sub 2 and I'm thinking that the bag that used to be Kenmore's call number was...20 A 5034. At least that was the catalog number as off Spring and Summer 1979.
Sorry for the over info...But Save that vac LOL!!!!