I know engineers are continually tasked with developing low cost solutions to designs, but I have to agree, this is just plain cheap. Expecially so, since there are so many proven design alternatives available. B&D used to be considered a quality brand - seems that they have had a change.
You gets what you pay for. Alot of posts seem to have communication errors and I wonder if this is another one. I looked at B&D product line and I didn't see a mainstream 28 VDC mower. Did you mean 36 V? And I guess this is a safety key? Its supposed to be useable by authorized, competent hominids with dexterity. Maybe the safety aspect was excluding you? Perhaps you should look into the Roomba line of autonomous mowers and take the human out of the operating loop to the greatest extent. Sorry but it is B&D, and though they started out as good quality USA made tools, they've been beaten down by the imports and now much of their stuff goes to the landfill everyday and is repurchased from Mallmart stores at equal flow-rate. So it goes in our red-white-blue economic model of gross consumption and disposal. Good luck with your field modification; hope it serves you well.
I have always had good luck with Black and Decker products. But I haven't purchased any new B&D products in recent years. The old ones have been working fine for a long time. I would be another heartbreaker to find you can't count on this brand any longer.
I too have had a recent Black & Decker problem. I needed a new corded string trimmer. I tried to to research on the internet by looking at owner reviews. There were lots of problems with older B&D trimmers regarding a plastic gear failing. Since there was a new model number I did some checking, and it appeared that B&D had paid attention to the problem. There were also comments about this trimmer using lots of cutting line. Some people had devised a method of getting around the constant changing of the spool.
So, I went ahead an bought one. No pully problem, but it does go thru trimer line like crazy. This unit has a very strong motor, and it might need a heavier line. But B&D makes it clear that the line they specify is the only size to use. I am afraid that if I go to a heavier line it will burn up the motor. I don't use the auto fee spool, but I cut a piece of line and loop it around the center post in the head. It still breaks at least one side very frequently. I am not sure, but I think the machine is made in China, not the USA.
When it works, it works great. I do not think that a well designed machine should use trimmer line as fast as this one does. I really do not know what the problem is, and I do not have a solution. As an older person it is nice to get the frequent breaks in the work of trimming. I just would rather have them when I wanted, not when I had to change the trimmer line.
I have used other brand trimmers, and they do not go thru line so fast. They have also not held up that well. Perhaps the only answer it to start using hand tools like in the 1950's.
I've gone through all types of string trimmers. I've had a gas trimmer, battery powered, and electric. The battery & electric units were both cheaply made and poorly designed with no means of repairing. Once they break, they're done. The battery powered unit had the brushes go bad, but the case would not come apart without destroying it. I've given up on using electricity for outdoor power equipment, and that's coming from an EE. To get something that's maintainable with a dealer network, I've gone back to gas power for all my outdoor equipment, and that's a shame.
I recently bought a 35cc gas trimmer and noticed it goes through trim line really quick and I know I don't go through that much since my other trimmer allowed me to trim for hours on the same feed. Anyway.. you can soak the line in water to make it less brittle and have noticed that reducing the engine speed on this new trimmer seems to really help conserve string.
The water soak is a trick that pro landscapers use to get high life out of their line. One word of advice is that all troimmer lines arenot the same. All are mostly nylon, but some are 6 and some are 66. Usually the higher the cost the tougher the line.
Uniquity, I too have had trouble with line trimmers. The device that gives you more line when you bang it on the ground seems to always fail for me. Then I'm stuck turning it upside down, pushing on the part you bang on the ground and trying to pull more line out. You need three hands to do it right.
Nah.. Don't need three hands to feed to line out on the weedeater. Just make sure you spool the string nice and flat. Don't criss-cross the string on the spool and no backlash. It should work perfect everytime. I wish I could fine a tap-and-go line feed for my weed eater. I hate cutting small lengths to carry around in my pocket only to find they fell out somewhere along my trek around the yard.
This is not always done due to cost considerations. Many consumer products are designed by persons, I may not want to give them the title of Engineers, that have limited experience. Add a fear of looking bad by showing it to others, and lack of formal design reviews and you get this. It takes hard won knowledge to be able to quickly think through all the options and select the best and others may still add to your work. Given design in a computer without any actual testing and production ends up making this.
I know someone who is a degreed EE who, as a brand new EE, was given the task by his boss of taking apart an LED based replacement for 4ft fluorescent tube made by a competitor and copying it, but cheaper.
Not black-box reverse engineering it, not challenged to make something better. Just to copy it while finding a way to make it even cheaper to build. He tells me that there is no one else there to ask as it is very cut-throat at that company, and that most are in the same boat as he is. No or low experience, and no-one to mentor him.
He didn't choose to become a potential "made by monkeys" engineer, but has become one by his boss's demands.
Why bother with a toggle switch? Why didn't you simply take a coaxial plug (barrel connector) and solder the two contacts together? And of course you must have fitted the charger with another barrel connector, right?
I am not sure if this key simply enables the running or directly starts the motor. If the latter, then connector contacts are not typically rated for connection under load while a switch is. p.s. I hope the switch used was rated for DC use or it may weld shut and make the motor impossible to stop.
Well, those coaxial barrel connectors are used for 100 watt laptop supplies. Given that their output voltages range from 16-20 volts, they ought to be good for 5 amps. And people hot-plug them all the time and I've never heard of any damage.
I thought about conduction/arcing/sparking during insertion and concluded that there must be another trigger on the handlebar that starts and stops the motor--you wouldn't want to extract and re-insert the key every time you find a branch on the lawn and stop to throw it aside. That trigger takes the brunt of the motor stop/start and, if properly designed, has a flyback diode across it to prevent contact damage.
Monkeys might forget the flyback diode. Chrysler forgot on the power door locks of my 1985 Caravan. They omitted the one on the air conditioner clutch too--the retrofit was a really crude fix. The diode was piggybacked on the spade connector to the clutch and covered with heat-shrink tubing which continued to shrink due to underhood temperatures until the diode was completely exposed.
I think I see your complaint. Why would you make a safety switch out of the electrical terminal that also charges the unit when your not even supose to pull plugs by the cord to disconnect them from the wall plug. Obviously the plastic molding is lacking when legos can be molded with more accuracy than something that could do some harm to a person. I bet those prongs are tiny too.
I am curious about the model # of the trimmers that have problems. I bought a new Black & Decker 18V "Grasshog" trimmer last year and am very happy with it.
The battery slides onto the bottom of the top end of the handle and counter balances the motor on the other end. Since you remove the battery and clip the charger directly to it, you can charge one while you use one as long as you have a spare. Since My trimmer came with 2 batteries, and the drill also came with the same battery, I'm all set.
It shares the batteries with my Drill of the same make. 3 Batteries, 2 chargers, no waiting. (OK one of the chargers plugs direct into the drill, so it's for after use)
This is not the most powerful trimmer or drill, but it works fine for me.
I recently worked on a cordless mower and it is clear that the first design priority is minimum cost to build the thing, followed closely by a willingness to give up quality and usability to assure that even the most determined fool will have a hard time getting hurt on thr mower. It was not possible to check charge state while charging, and it was very inconvenient to disconnect the charging cord to enable readings.
That is why I continue to use electric mowers with a power cord. They don't last as long as the older gas engine units used to last, but I think that eight years average for a used mower is OK. They take less maintenance, once the starting interlock is removed, and they are always ready to use, never dead batteries.
The trick is to use an orange cord with the mower, and to never run the mower over the cord. Avoiding the cord is jalmost as simple as always avoiding ones toes. I do wear cords and mowers out, but don't break them.
You're right William. I still use a cordless mower and there are some real issues with the batteries. They unit came with SLA cells, which are heavy and only last about four years. I'm on my third pack now and have switched to NiMh since that technology can now pack a little bigger punch when the starting current is over 30A. I have a 10AH, 20 D cell, which is 10 lbs lighter than the 17AH SLA cells and has about the same run time. If you can believe the specs., I should get a few more years out of these cells. I toyed with going to LiFePo, but the cost is still very high on those cells, so maybe next time.
It's pretty easy to gauge the State Of Charge on SLAs and the original electronics in the mower did this pretty well, but it is impossible to do an SOC on NiMh cells. I removed the original electronics for charging and designed a little solar charger, so now I have a green mower. It takes about three sunny days for a full charge and I have never had to supplement the solar charge, but if I were to do it again I would get a corded mower.
Good info, William. I had no idea gas mowers lasted longer than electric mowers. In my experience, it's been the opposite. As for the cord, after many years of using electric mowers, I never found that the cord was a problem. These days I have a small yard, so I'm back to the days of my youth with a push mower. It's a simple and lovely contraption.
I had no idea gas mowers lasted longer. I've had no problems with my electric mower, kind of looks like a little car with its lazyman start. It was a nice change from the gas one I used on my family's farm , which didn't have an easy starter.
The devices that get advertised with higher battery voltage are not better just because of that. The point of higher voltage is to achieve lower current, which means the manufacturer can use thinner cables. These cables need a bit more insulation, but plastic is way cheaper than copper.
Same for the plug, the design is most likely based on economics rather than usefulness with the intent to break after warranty is over while making 'official' repair cost prohibitve. The point is that customers go and buy something new.
I worked as a component supplier to Dewalt in the late 90's when they introduced 24 volt tools that they thought would sell like wildfire. I do not know the exact numbers, but we did not supply to them as many components as was planned. Consumers thought that they were too heavy and too expensive and bought the time tested 18 volt instead.
There is a good lesson to be learned here. It doesn't matter how much of your heart and soul you put into a design, when it comes down to it, your shortcuts will destroy your reputation. I am sure the mower was designed very well and worked as advertised, but all this goes down the toilet when you design the part that every customer will deal with almost every day to be flimsy, ugly, bothersome, unwieldy, or otherwise Mickey Mouse (no offense to the king of mice). The little things will kill you!
When you buy something that is packaged well, good looking, nice graphics, and so on, you suspect that you have a quality item. You buy a Mercedes, you expect and get a loaner car, and your car is returned vacuumed and washed. When you buy a Craftsman tool, you expect to return it for a new one if it breaks. When you shop at a great grocery store like Price Chopper, Whole Foods, etc., you get and expect great produce and good service. When you buy a name brand item, like Black and Decker, you expect a good product with good features. You don't expect a piece of wire to be the key. Shame on them! There goes a piece of Americana...
I had a gas mower that lasted over ten years and was still running when I gave it away, but...... I had to rebuild the carburetor every couple years. The carburetor body of the Briggs and Stanton engine appeared to be made of nylon and metering was performed by an odd, neoprene baffle separating the two halves of the carburetor. The neoprene part would wear out and needed to be replaced, which meant pulling the carburetor off, disassembling it, and replacing the neoprene part every couple of years. I bought a handful of the strange little baffles and kept them in the garage so I could replace them whenever the mower started chugging.
Another case of going cheap; carburetors used to be made of metal and the metering was performed by needle valves that yielded years and years of surface before cleaning was required, and that was cleaning, not replacing. I went electric too, and then gutted the charging electronics to go solar.
When someone posts a problem with a gas mower I wish they would include brand or at least type. I have gotten years of service from power mowers with both Briggs or Tecumseh 4 cycle engines. But I did have some problem with a Lawnboy 2 cycle engine. I also torched a 2 cycle Mercury outboard and the mechanic told me the addition of ethanol into our gasoline causes a break down in the gas/oil mix which in turn causes excessive engine wear. Perhaps that was a contributer to the Lawnboy issue.
I do not know how true that is, but the marina where I store my current boat only sells gasoline which does not contain ethanol. I do enjoy the ease of starting electric, but it is totally impractical in my yard which is 3/4 acre and gets mostly mowed by a riding lawn mower, also a 4 cycle engine.
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