Sunday, December 18, 2011
How to Re-wire a Potted Motor, Part 8: Motor Housing Removal
Now that we’ve got the motor leads disconnected (as shown in Part 7), we need to remove the motor housing in order to access the motor.
To get to the motor housing, we first need to remove the handwheel. I would ordinarily also disassemble and remove the bobbin winding assembly, but because that is an operation in its own right, I will save that for another entry and leave it attached to the motor housing. (Leaving the bobbin winding assembly on is not “standard operating procedure” for me, but as long as we are careful, we should be fine.)
We start by loosening the set screw in the stop motion wheel:
Don’t take it out all the way, just loosen it to the point shown in the photo below. Leave it in place to reduce the chance of losing it (I often see these missing on Singers I acquire). We only need to loosen it enough to get the stop motion wheel off.
Unscrew the silver stop motion wheel. Unlike the photo, in reality you’d have to use your other hand to hold the handwheel steady, but my other hand is holding the camera. Remove it carefully, keeping at least four fingers on it at all times, so it doesn’t fall out and chip the enamel on the handwheel (been there, done that).
Next pull the washer out by pinching one of the protrusions between two fingernails. If you’re not careful with the washer it, too, can suddenly fall out and chip the handwheel's enamel.
Now grasp the handwheel firmly and pull towards you. If it doesn’t slide off easily, wiggle it north-south and east-west while pulling it towards you.
Even with old grease sticking it in place, it should eventually come off with just hand pressure. (If it does not, tell me in the comments and I’ll prepare another entry showing you what to do.)
Now we turn our attention to the handwheel, and a choice of how to proceed. My preference is to clean parts as they come off of the machine, so I can store them clean while I finish the job. I also don’t like to handle dirty parts and then work on electrical stuff. So before I go any further I’m going to give this handwheel, the fiber gear, and the handwheel housing a cursory cleaning. You can of course skip ahead, because we’re on the internet and I can’t see you. And if I can’t see you, I can’t nag you.
To clean the handwheel’s innards I use these two implements that I bought for a few bucks at an art supply store, I believe they’re used for sculpting clay. (You don't need to buy these, read on.)
The one on top has a flexible metal tip. The one on the bottom has a silicone tip, here’s a close-up:
I use the metal one on the metal parts and the top of the gear, scraping the grease off.
The silicone one I use to “squeegee” between the gear teeth.
Every morning when I get my coffee-to-go at the diner, the diner guy gives me a wad of napkins. He probably thinks I’m going to use them to wipe my mouth after drinking the coffee, and he’s wrong.
I could do a whole entry on how to clean a handwheel, and one day I will. But I have to finish this series first. In any case, I get the wheel looking like this:
You don’t have to get it that obsessively clean, but I’d at least get the bulk of the old, hardened grease off of the thing. If you don’t want to buy the tools I mentioned above, you can probably find something in your kitchen. I wouldn’t recommend toothpicks--you don’t want splinters in the gear teeth--but maybe some plastic utensils, or one of those little plastic swords they put in cocktails.
If you clean the black part, I’d advise not to use anything other than a wet Q-tip and a lot of elbow grease. The bobbin winder tire rides on the inside of the handwheel, and if there’s anything slippery on it, like the sewing machine oil some people use to clean their machines, the tire will slip and the oil will eventually rot the rubber.
Handwheel finished, now we turn to the housing. In this case it’s pretty filthy; this machine is from 1937 so the lint is probably historic.
I remove the lint and hair with a small bristle vacuum attachment.
Then I go at the inside with the metal clay tool and burn through some more diner napkins.
Afterwards I scrub the insides with Q-tips moistened with rubbing alcohol. (If you go this route, be careful not to spill any alcohol on the outside of the machine. Alcohol is fine on bare metal, but it will eat through, and ruin, the exterior finish.)
Now it looks a damn sight better than before:
More importantly, with all of the excess grease gone, now I can actually see the two mounting screws inside.
We need to remove those two screws. A Brownells bit #360-6 fits perfectly. These two screws are often in there REALLY tight, so I often stand up and lean my body weight into the screwdriver, really pressing it into the screw, and then begin loosening it. To do this I often have to hold the machine with my other hand, but again, my other hand is holding the camera.
Once the screws have been removed, here’s how we’re going to remove the housing. You know how in the movies, when somebody’s fake-driving and just wiggling the steering wheel back and forth? That’s the motion we need. Do this GENTLY, please, and use both hands. My left hand is on the camera, but should be where the red lines are in the photo below. Be careful NOT to grab the bobbin winder assembly.
The extremity of the tilting of the housing is exaggerated in these photos, just to give you the idea. Do this as gently as possible!
As you continue wiggling the housing back and forth like a steering wheel, pull it towards you. Eventually you’ll feel it loosen and you can slide it off of the shaft. Easy does it.
Now your motor’s off. Set it down and go pour yourself a cocktail (even though you might be out of swords).
Go on to Part 9: Removing the Grease Wicks