Singer 31-15: How far can I go before I get myself in trouble?
 

I have a 31-15 that I started to restore last year then set aside.
Pulled it out today and got back to it.
(I know it's not traditional but I think it'll look quite nice in maroon)
The internals aren't rusted - but neither are they nice. Let's call it mild surface corrosion.
Not in the needle bar area but inside the upper housing and underneath.
How far can I take things apart before I get into trouble?
By that I mean there doesn't seem to be a "shop manual" for these and I don't want to get into a situation where I'll never be able to get it back to proper timing etc.
Lew

Up in that area you might try some bicycle chain oil it is for dealing with rusty bike chains. Some times it will remove the rust by friction. Then brush off the rest. I have had success with that a time or two.

I would hold off dis-assembly and begin instead by sitting the machine in a shallow pan and repeatedly sloshing kerosene through it. Dab with a stiff, stub (cut-off) brush where you can reach. Best done outdoors because of the stinky quality of kerosene, but it works beautifully as a solvent and temporary lubricant. After it dries, you'll have to lubricate with standard sewing-machine oil. The 31-15 is a simple machine, so it should respond well to this treatment, and flush superficial oxidation.

Maroon sounds nice. Please post photos when you do it.

I'm thinking Joe uses transmission fluid

Kerosene, then ATF, then Hoppe's #9 gun solvent is the order of things for those machines that are so dirty with caked on oil and debris that sewing machine oil won't do it.

I've never had one that was so bad in the upper arm that I had to take it apart, but I have removed all the inspection plates and cleaned as much as I could reach, then flood it with sewing machine oil to flush out the rest.\

Joe

Good ideas!
Thanks. My natural instinct is to disassemble and polish everything but discretion is the better part of obsession....so to speak.

caked oil and rust rarely are in the same place

My internals aren't nearly as bad as all that.
Just not nice and shiney... which I find vaguely disconcerting.
My guess is a spray of WD-40 followed by a good brushing and wiping and then oiling will do just fine.

I hate WD-40

Hmm - I'm not a fan of WD-40 as a lubricant mainly because it really isn't but as a cleaner I find it effective.
Perhaps you can help me understand why its use in this situation would be inadvisable?