Motor working, blades not operating. How do I fix it?

L. P. Nixon, May 2008

I need the black handle also!

jim, August 2010

If you cannot repair; I need the handle for the U-272
shrub and hedge trimmer.

harvey, August 2008

The usual cause is worn out worm teeth on the armature shaft, or a worn out bushing in the gear center - it wears out on one side and becomes egg-shaped; either way, the teeth no longer make enough contact to move the blades. It is possible that the worm teeth stripped completely off the armature shaft, in which case the entire armature will need replacing, but I think the gear is tough enough that those teeth won't wear out. If either the worm teeth or the gear bushing are worn out, the worm teeth slip by the gear teeth and the motor will spin but not the gear or the blades; the gear bushing can be pressed out and replaced - but finding just the right size is almost impossible! I've got mine apart right now, and am trying to locate parts - with no luck so far. I'll add a note if I find a source.

John, June 2008

Hello, My ancient U272 Black & Decker hedge trimmer just broke down yesterday, so I took it apart today and it has been quite a challenge getting it back together but worth finding out how it works and discovering that it has fine machined metal parts throughout (made in USA), no plastic, so it can be repaired if we can find parts. It really is nicely designed and built to last for almost forever. However, the blade stopped running on mine because the either the main worm gear was worn and/or it was jammed up with about 20 years of greasy composted hedge trimmings. The thick grease the main gears need also traps fine clippings and dirt. I am replacing the old grease with Valvoline multipurpose grease for bearings, etc.. The wires from the armaure to the brushes broke off both brush housings when I took it apart and the tiny brass clips are very delicate. I will have it back together tomorrow after soldering the wires back on to the brush housings. Can you tell if the motor stopped or did it keep running but the blades stopped? If the motor stopped, it could be clippings around the armature, or the brushes that drive the dynamo could be worn out (easily replaced). If the motor kept going, but the blades stopped, then I suspect the worm gear is worn. Unfortunately the worm gear is also part of the armature of the electric motor. Even if I get it going tomorrow, I will have to replace this worm gear in the near future as it is about half the diameter it is suppose to be from wear. It is amazing that it still worked in this condition. I am currently looking for used parts on the internet. If you are not mechanically inclined and don't like greasy puzzles with lots of loose parts (bushings, springs, washers, etc), to put back together, I don't recommend taking it apart yet, at least not without some help. If I get mine running again tomorrow and can confirm it is indeed the worm gear malfunction I will post another message. I know this might not get your hedge trimmer running but might help you decide about a new trimmer. I am determined to repair mine if I can find a junker or some parts, because it is so well built inside, despite the fact that both or ours are busted at the moment. But after seeing how the parts have to work, I am surprised these antiques have lasted so long. This trimmer has to be at least 25-30 years old. More later.


Sam

sam, June 2008

Hello, My ancient U272 Black & Decker hedge trimmer just broke down yesterday, so I took it apart today and it has been quite a challenge getting it back together but worth finding out how it works and discovering that it has fine machined metal parts throughout (made in USA), no plastic, so it can be repaired if we can find parts. It really is nicely designed and built to last for almost forever. However, the blade stopped running on mine because the either the main worm gear was worn and/or it was jammed up with about 20 years of greasy composted hedge trimmings. The thick grease the main gears need also traps fine clippings and dirt. I am replacing the old grease with Valvoline multipurpose grease for bearings, etc.. The wires from the armaure to the brushes broke off both brush housings when I took it apart and the tiny brass clips are very delicate. I will have it back together tomorrow after soldering the wires back on to the brush housings. Can you tell if the motor stopped or did it keep running but the blades stopped? If the motor stopped, it could be clippings around the armature, or the brushes that drive the dynamo could be worn out (easily replaced). If the motor kept going, but the blades stopped, then I suspect the worm gear is worn. Unfortunately the worm gear is also part of the armature of the electric motor. Even if I get it going tomorrow, I will have to replace this worm gear in the near future as it is about half the diameter it is suppose to be from wear. It is amazing that it still worked in this condition. I am currently looking for used parts on the internet. If you are not mechanically inclined and don't like greasy puzzles with lots of loose parts (bushings, springs, washers, etc), to put back together, I don't recommend taking it apart yet, at least not without some help. If I get mine running again tomorrow and can confirm it is indeed the worm gear malfunction I will post another message. I know this might not get your hedge trimmer running but might help you decide about a new trimmer. I am determined to repair mine if I can find a junker or some parts, because it is so well built inside, despite the fact that both or ours are busted at the moment. But after seeing how the parts have to work, I am surprised these antiques have lasted so long. This trimmer has to be at least 25-30 years old. More later.

Sam, June 2008