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Whatever Happened to ... Twin-Blade Electric Mowers?

Posted by oldlawnmowerman81 Milwaukie (Oak Grove (My Page) on
Tue, Nov 2, 10 at 21:33

Hi,

Does anyone here remember the twin-blade electric mowers? These were made by such makes as Sunbeam, MTD and Black & Decker, among others.

Unlike their single-bladed counterparts, twin-blade mowers run at higher speeds (read: two blades instead of one, obviously). I have a 1983 Sears Craftsman 91412 model (with the CPSC-compliant switch that you must hold down to turn motor on, let go and motor shuts off).

Sunbeam (later Aircap-Mastercut and MTD) and Black & Decker are two of the well-known manufacturers behind mowers like these.

Among the twin-blade mowers I'd like to find in the future:
Black & Decker U-273/8020 18" deluxe twin-blade mower
Black & Decker 8021 18" deluxe twin-blade mower
Black & Decker U-275(?)/8040 22" deluxe twin-blade mower
Black & Decker 8041 22" deluxe twin-blade mower

Regards,


Ben (OldLawnMowerMan81)

Here is a link that might be useful: Vintage 1956 Sunbeam Twin-Blade Rotary Mower


Follow-Up Postings:

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RE: Whatever Happened to ... Twin-Blade Electric Mowers?

I have an older twin-blade electric mower, and a newer Craftsman (I think) electric mowers out back in the barn. both run good. I get calls for one every so often, and they don't eat anything in storage. The price i get is usually low. Young and old ladies with small lawns like them.


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RE: Whatever Happened to ... Twin-Blade Electric Mowers?

I would think the reason for the decline of mowers like these, which I believe the last year sold was 1990 and was made by MTD (having inherited the tooling from the Aircap-Mastercut company by that point), was due to the fact that because there are two blades, they both had to be sharpened.

I don't believe these ladies would've liked doing that - maintaining not one blade, but two.

And I also believe another reason for their eventual decline was their price tag. I know Black & Decker's 8020 (formerly U-273) 18" twin-blader retailed in 1971 for $79.99 which was higher indeed than their deluxe 18" single-blade model 8010 (formerly U-272?), which went for $20 less at $59.99.


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RE: Whatever Happened to ... Twin-Blade Electric Mowers?

Cost of maintaining 2 blades might have been one reason, but I'm guessing that most buyers of $60.00 mowers paid scant attention to regular maintenance. I wonder if modest cutting ability might be the other?


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RE: Whatever Happened to ... Twin-Blade Electric Mowers?

Let me throw in the issue of belts, too.

Unlike single-bladed electrics, twin-bladers used belts to bring down the speed of the motor. The B&D models used flat, fiberglass reinforced belts (to operate w/o overheating), while the Sunbeams used toothed timer belts, necessary as their side-by-side blades must be synchronized so they don't collide with each other.

This could be another reason the twin-blade mower faded into obscurity. Not just two blade maintenances, but also the belts.

~Ben

Here is a link that might be useful: Here Come the Electric Mowers!


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RE: Whatever Happened to ... Twin-Blade Electric Mowers?

I have a black n decker u273. Can you tell me anything about it including it's value? Thanks Jennifer.


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RE: Whatever Happened to ... Twin-Blade Electric Mowers?

I'd set it out in the front yard, with a "for Sale" Sign on it, and state that it is electric/ 110 Volts, and i'd be willing to bet it will sell quickly! You could even get rid of an older, but usable extension cord with it.

When i have one for sale, i can get from $50 to $75 for them, depending on condition and how it sounds when running. Folks with "postage stamp" Size yards love them. Folks with large yards usually end up with a big bunch of extension cords missing their ends! (Think about that--_chop-chop!)


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RE: Whatever Happened to ... Twin-Blade Electric Mowers?

I have a Black&Decker model 8015 mower I bought in 1974. It has worked well for all these years. I replaced the belts thrice, and the brushes twice. All the bushings and blades still work fine.

This afternoon it died. It made those slowing down gurgling noises, started smoking, and smelled like melted insulation.

Where can I find a motor for this mower? I doubt I can find one easily, and if I can it will probably cost four times what I paid for the mower. Any help will be greatly appreciated. I really like this thing, and you just can find twin-blade mowers anymore.

Thanks for any help,

Bob


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RE: Whatever Happened to ... Twin-Blade Electric Mowers?

@Gyrobob
I'd rather find a model 8021 or the 22" cut version the 8040, since both are deluxe and that the one you have is the bottom-of-the-line version.

Also, I'd like to try and get my hands on a model 8018 18" single-blade deluxe mower from 1984-88.

~Ben


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RE: Whatever Happened to ... Twin-Blade Electric Mowers?

Hi! Someone just gave me a B&D 8021! He had tried to sell it at a yard sale for $5, but had no takers. It looks like it's barely been used all these years, or that it's been extremely well maintained. I've used it twice now to cut my (much larger than postage stamp sized) lawn, and it works well, but this the motor does tend to get very hot, and then it changes tone and sounds quite unhealthy. That's when I shut it down to let it cool off. Is there anything in particular I should know about this mower so I don't kill it?


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RE: Whatever Happened to ... Twin-Blade Electric Mowers?

Twin-blade electric lawn mowers have not entirely disappeared, but they sure are an endangered species. We have a proud fleet of three twin-blades, all bought at garage sales, and all of then still bravely mowing our lawn. We have a Sunbeam model RE-184A; a Lawn Master of identical design; and a Black & Decker model 5740 Type 3.

The smoothest running of the lot is the Sunbeam, whose plastic handle has long since decayed in the sunlight, and fallen off, leaving us with only a steel shaft to hold onto. I bought it at a yard sale, by accident. The lady wanted five dollars for it, and I casually asked if it worked. She insisted on showing me that it did, and dug out an electric cord and connected it up. The poor machine let out a shriek of misery worthy of a bad horror movie. Smoke, and flying parts. I doubled up laughing. "Well, two dollars!" she countered. I had to buy it. Rebuilding it cost less than a new mower.

These machines are much misunderstood. There is an electric motor in the middle, and a drive shaft for the cutting blades on each side. The drive shafts have a porous bronze bushing (expensive) at the top and middle, with an oil reservoir between the bushings. There are two independent blades per shaft, and the shafts are driven by toothed rubber belts (3/8 in., 50 teeth, part no. 47-81752).

It in not sufficient to oil the motor. You must also keep oil in the two oil reservoirs for the drive shafts. These are filled by removing a screw on the outside of the mower body, and squirting the oil in. The reservoirs are not connected, so each must be topped up. For want of better advice, I use light motor oil, with some Moly-Slip mixed in, in case of oil loss. Since replacing the shafts and bushings, it has run like a Swiss watch for the last twenty years.
The motor is oiled with 3-in-1 electric motor oil, by removing the plastic cover - 5 drops of oil into the oiling hole on top.

Balancing of the independent blades is important, and if you sharpen the blades, you will change the balance. That can result in destructive vibrations. I made a balancing tool out of a piece of strap steel. It holds the two blades opposite each other, as they would be in service, and sits on a knife edge, which makes it fairly sensitive. Simply weighing the two blades is not enough, because both position and weight are important.


Problems with twin blades:

Properly cared for, these things last for ever. Unfortunately they had a high failure rate, and because of their complexity, high production costs. So they gave their manufacturers a bad rep, and gave the cost accountants headaches.

One big advantage to the single blade mowers, is that the bearing is in the motor, so all the mower manufacturer has to make is the mower body and one blade. Man, that must feel better. For the user, balancing and lubrication are also much easier.


Maintenance:

Twin blade mowers are good machines, and they last perfectly well if you maintain them. Most died of neglect. Most people do not want to take the time to lubricate and balance them. Then there are other problems. One of my pals lubricated his Sunbeam with WD-40. He went through several sets of bushings every summer. He finally junked the poor machine in disgust. Most people just forget, and the mower runs dry and burns out its bushings. Here's what to do:

(1) Remove the plastic cover and give the motor 5 drops of someone's "oil for electric motors" at the beginning of every summer. Adjust for different work loads. I use 3-in1 oil for electric motors. Note: these oil holes on electric motors are usually a small reservoir stuffed with dense felt. The felt keeps dirt out, holds the oil, and releases it as needed. In a new motor, you may need to soak the whole felt wad at first oiling.

(2) Remove the seal screws, and top up the two oil reservoirs for the two drive shafts. Use a light oil - not WD-40 which is a penetrant, and not a bearing lubricant. Replace the seal screws when finished.

(3) Turn the (UNPLUGGED) mower upside down, and oil each of the four cutting blades, so that they pivot easily. Wiggle them until the oil penetrates the pivot joint. If they don't pivot, your machine may vibrate badly.

(4) Replace badly damaged blades, in pairs. Balance each pair before installing them, so the machine runs smoothly. In fact, balance them yearly. It's a lawn mower - not a vibrator.

Parts:

Manufacturers rarely make the whole machine. For example, a lawn mower manufacturer probably doesn�t make the nuts and bolts used in its machine. Rubber drive belts are made by rubber belt manufacturers, and are picked out of a catalogue. Electric motors, wires, gears and sprockets, wheels and rubber tires, nuts and bolts are all picked out of special catalogues. So, when your Sunbeam needs a new motor, and Sunbeam no longer supplies it, chances are it is a standard industrial motor with a standard industrial mounting, and if it was at all popular, it is probably still in use in other machines. Check with the appropriate manufacturer. For rubber belts, call the rubber belt people. They won't know anything about Sunbeam, but they will find a match for your belt fast enough. Beat the bushes before you give up.

Happy mowing.


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RE: Whatever Happened to ... Twin-Blade Electric Mowers?

Hi,

Does anyone know how to oil this B&D twin-blade mower?

Thanka,
Brian


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RE: Whatever Happened to ... Twin-Blade Electric Mowers?

I was given a really cool Sunbeam twin blade electric lawnmower model RE18TS and would like to know if anyone may have an owners manual for this model. It's in running condition but does need a new belt and two rear wheels. Anyone have spare parts for this that they would want to sell?
Any help or suggestions would be appreciated.
Thanks
Art Rietveld


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