I recently purchased an inexpensive, 3.9 lb. Black & Decker 12" Trimmer/Edger. This is actually a "Bump Feed Trimmer", not an "Automatic Feed Trimmer", which were more expensive. I don't need an industrial strength weed eater for my small yard. I just needed enough horsepower to trim about 70 linear feet of regularly growing hay-like weeds, and the weedeater needed to be lightweight enough that I wouldn't get tired of holding the machine after 10 feet of use. The big illustrations in the instruction manual make it easy to assemble the edge guide and guard attachment. There's only one screw. Plug it in, squeeze the trigger, and you're ready to go. But it's not quite that simple if you've never operated a weed eater before, which I haven't.
Now here's the mistake that I made... The nylon string gets chewed up quickly when you're cutting through hay or hitting vinyl siding or cement with it. Within a foot of use, my cutting string was either gone or nearly gone and my Black & Decker Trimmer/Edger was practically worthless for cutting grass. So I turned the weed eater upside-down and pulled on the string to try to feed more cutting line out, but that cutting string wasn't budging. Ah, the cutting string must have somehow gotten stuck in there, I thought to myself. I pulled off the bump cap to find out how much string was actually on that spool and to free the string from wherever it had gotten stuck. The spool popped off of the spring, the cutting string unwound itself from the spool, and now I had a BIG mess on my hands. I thought I had broken my brand new weed eater.
But I was able to rewind the cutting string tightly around the spool, and thread it through the little hole in the spool flange just like a bobbin in a sewing machine. I gave myself about 3 inches of cutting string to work with, but I didn't worry about it if I pulled the cutting string out beyond the guard attachment because the guard attachment will cut off the excess string if I've fed through too much for my own safety; a feature that I like about this Black & Decker Trimmer/Edger. I held that spool down firmly on the spring and replaced the locking bump cap overtop of it to hold it in place. And I was happy to note that it was going to be fairly easy to replace the spool of cutting string when I finally did need a new one, a mild concern to me when I bought this machine.
Now mind you, I have 70 linear feet of weeds to eat, a string that gets chewed up about every foot or so, and I successfully whacked and cleared 60 linear feet of weeds before I discovered how to use the "bump" feature to feed more cutting line out whenever I needed it without having to take apart the entire spool assembly to do so. I would estimate that I took the spool assembly apart and put it back together at least 40 times in the couple of hours it took me to whack through 60 feet of weeds the hard way, a testament to the durability of the parts used in manufacture that they can hold up through many cutting line spool replacements over the years, or even just hold up through one afternoon spent with one genuinely confused novice weed eater operator.
When using the Black & Decker Trimmer/Edger, when the cutting quality is starting to go down, press the bump cap (the bottom of the weedeater) firmly on the ground while you're still holding the trigger to make it run, and this will release a little more cutting string out of the spool for you to slice right through that thick hay. That's the "bump" feature of the Black & Decker Bump Feed Trimmer, and something that the instructions didn't explain very well for brand new users. I was bumping the sides of the darned thing and wondering why it wasn't feeding out any line like it had promised to, and seriously considering taking it back to the store to buy a different model that actually worked when I bumped it against something.
To use the sidewalk edging feature of the Black & Decker Trimmer/Edger, the instructions tell you to push down on the trimmer head collar, then rotate the trimmer head clockwise. The first few times I tried to do that, I got nowhere with the trimmer head because it was so heavy and awkward to turn. But when I pushed down on the trimmer head collar and rotated the lightweight aluminum handle instead, now that was a very simple and quick transformation from Trimmer to Edger and back.
The Black & Decker Trimmer/Edger comes with a 2 year warranty against defects in material or workmanship, but states that a proof of purchase may be required even if you're shipping it Black & Decker Service Center for repairs and not just taking it back to the store. So I would recommend keeping the store receipt stapled to the instruction manual until the warranty expires.
All in all, I'm very pleased with the Black & Decker Trimmer/Edger, and I would recommend it to anyone who just needs a light-duty weed eater that's inexpensive, lightweight, and easy to operate.