A Quick Build: Fixing the World's Greatest Toaster

In reply to CJ :

Correct, this is indeed a Sunbeam T-20! According to the date under the crumb tray, this one was made in 1955.

I'm glad to see we have so many toaster enthusiasts in the comments :)

Once I got it home, it was time to find out if my awesome toaster was functional. The first thing I noticed was that the "one slice" label was adjacent to the wrong slot - someone had taken the cover off before, but perhaps that means that it has already been repaired and it will work! Armed with a wooden spoon to push the activation lever, I plugged in the toaster and depressed the mechanism and... nothing. The toast wasn't going to be that effortless after all.

From my research, it appears that 95% of non-functioning Sunbeam T-20 Toasters can be fixed by adjusting the screw in the center of the toaster under the crumb tray.

This adjusts the tension of the mechanism - if it is too loose, the toast elevator will fall before it can activate the main switch. I tightened the screw to the correct tension, reinserted my wooden spoon, and... still nothing. I could hear a brief electrical engagement, but the toaster wasn't staying switched on. it was time for that shiny chrome skin to come off.

While I have the cover off, how about a brief explanation of how the Sunbeam T-20 (and derivatives) works, for those who may be unfamiliar with the incredible genius of these machines.

The T-20 is an automatic toaster. When you put your bread in the slots (or just the right slot, if you're making one piece) the bread silently and gracefully lowers itself down into the toaster, where the heating elements toast it just like any other toaster. However, unlike other toasters, this one uses a bimetallic strip thermostat to determine when the toast is hot enough to be considered "toasted," and once it is finished the toast rises out of the toaster in the same automatic fashion. The true genius, and my favorite part, is that all of these systems are interconnected, like a compact electromechanical Rube Goldberg machine.

When the bread is inserted into the "one slice" toast slot, it depresses a lever that goes to a switch that engages the bimetallic strip at the thermostat.

You can see the lever mechanism (orange) exiting the toaster on the right side in the above picture. The dark scoop-looking thing it terminates at is actually a cover that keeps the lever from resting on the transfer arm after it has initially activated the toast cycle. When you begin toasting, it is not blocking the lever like it is in this picture. The transfer arm is the flat metallic strip (green) behind it, and that transfers the motion through another lever (blue) to the thermostat switch (red):

Once this connection is made, the circuit for the heating coils is active, and they begin to heat up. The connection stays intact until the bimetallic strip deforms enough to build enough spring tension to pop the connection back open. All simple enough. But the best part is how the automatic raising and lowering mechanism works.

As I said, the T-20 raises and lowers the toast automatically, and it does this by exploiting the thermal properties of the heating elements themselves, which I just think is the coolest thing. Essentially, in the center section of the toaster, the heating elements are wound in a spiral around a central frame that is able to expand or contract in width - the central frame is pushing its sides against the heating element wire. While it doesn't show the frame in great detail, this diagram should give you a rough idea of what I'm talking about:

When the thermostat switch is activated, the wire begins to heat up, expanding ever-so-slightly, allowing the sides of the frame to push out juuuust a little bit, and by doing so they pull the hinged bottom of the frame up ever so slightly. This motion is amplified and reversed by the levers you can see on the side of the toaster, which connect to the toast tray, and thus the toast is lowered as the heating elements heat up until it reaches the bottom of its travel, and once the thermostat deactivates the switch, the wire cools down and the whole process reverses. It's elegant, silent and beautiful to watch... when it's working.

(Also if anything about the toaster mechanism is unclear you really should watch Technology Connections videos on these things. He explains it  a lot better than I do)

This brings us back to the problem at hand: my toaster wasn't working. I knew I was getting power, and I knew that the central raising and lowering mechanism was tensioned correctly. After I finished figuring out how the whole thing was put together, I noticed that the switch was not staying closed when I activated the toast lever. I surmised that the thermostat was out of adjustment, which is an easy fix. The toast darkness knob actually adjusts how much tension is on the thermostat, so by tightening the knob I was able to bring the thermostat back into spec, and the switch stayed closed!

Too closed! The toaster would now go through it's toasting cycle, but the switch wouldn't disengage so I would have to unplug the it to avoid catching my house on fire. After many rounds of blackened bread, I finally found the correct tension for the thermostat, the toaster went through the toasting cycle correctly, and I finally made my first piece of edible toast!

Not pictured: the stack of burnt toast just out of frame.

Great thread and definitely will admit to running a quick search of toasters for sale in my area as a result. 

Here's a quick video I took of the first successfully toasted toast emerging from the toaster. Unfortunately I didn't think to film the next bread going back down, but you get the idea :)

Also, as a note: these toasters get hot! When the chrome skin is on it isn't bad, but the whole thing is metal and there really isn't any insulation to keep the heat moving from one place to another, so messing with it with the cover off should be done with care.

I love it! We had one of those back in the day, as almost everyone did. So much more elegant than the ones we have now that try to launch the toast into the air!

Weird this popped up.  Spent most of yesterday troubleshooting the maybe 25yr old Dualit - bad clockwork timer switch, it turns out.   I'm always amazed how easy it is to repair - a philips screwdriver and, well, nothing else really.

Now, in the interests of full disclosure, the "troubleshooting" included about four minutes with a voltmeter to figure out it was the switch, and the rest of the day taking both end castings off and giving them a little 320/400/600 grit love.  Followed by some scotchbrite and then the orbital polisher.  *Two* coats of wax, now, Biff...

This toaster is like magic. I didn't know a toaster could be so cool. Toasters like this where probably way above my family's budget. 

Having more than one Dualit obviously classifies me as a "toaster enthusiast" 

I'm in for this thread

Trent said:

Having more than one Dualit obviously classifies me as a "toaster enthusiast"

[wheels in head start making Dualit clockwork whirring noises] a *backup* Dualit toaster, you say?  I wouldn't have to wait, sans toaster, until eBay sends the new switch, you say...?

Now I am wondering if I can mod my current toaster with a bimetallic strip to get it to toast more consistently. Or maybe I should just track down a vintage Sunbeam too. This thread makes me wonder why this design isn't more common.

It's been a busy week but I'm back to continue my toaster odyssey!

Now that my toaster was making toast, I really only had one more task to do before buttoning the whole thing up again: replace the ancient, sketchy, cloth insulated plug.

I noticed it would heat up whenever I would turn the toaster on, it wouldn't stay in the outlet very well, and it was so small it would barely cover the holes in the receptacle. Overall, just not safe. I bought a new plug from Lowes for $10 and cut it down to about 3 feet long. The old wires looked like this where they terminated (apologies for the terrible pic):

Again, pretty sketchy. I don't think it came from the factory this way. I put ring terminals on the new plug and managed to squeeze everything into the tight space that the toaster has for its wiring. Polarity doesn't matter, so I didn't have to worry about which pole to attach which wire to. The new plug is grounded so I attached the ground to one of the other bolt holes on the bottom of the toaster. Practically the whole thing is metal so finding a grounding point it easy haha. When I put the whole thing back together the ground is sandwiched between the metal toaster body and the black plastic base.

After running a couple of tests to make sure it worked, the toaster was ready for its shiny metal cover to go back on.

Time to finish the story of this toaster restoration.

After I hooked up the new plug, I slipped the plastic base back on and realized that my wore orientation wasn't going to fit - there's not a lot of space for the extended length of the crimp connectors I was using, since the plastic base has some molded areas that get in the way. But with a little messing around I was able to get the wires looped around in an unobtrusive way and attach the base. After that, it was just reattaching the cover after giving it a good scrub, and voila! A functional 67 Year old toaster that looks as good as it works.

 I've been using it as my regular toaster for a couple of months now and it's wonderful. I never have to worry about my bread being over toasted, and it's much faster than a modern toaster to boot. The silent automatic operation still tickles me every time I use it. This concludes my toaster story, as I expect it will run reliably for many years to come. Thanks for reading my thread!

Just picked this up through random Facebook find. First pass shows it turns on and heats immediately to full tilt and does, after unplugging, raise burnt toast. 

Looks like a great example, and $15 is a steal! I suspect the toaster not shutting off is a poorly adjusted thermostat, same as mine just in the opposite direction.