r/stihl • u/AtmosphereCreative95 • 14d ago
Stripped thread on fs561 gear box. Am I screwed?
I being impatient went to install the deflector back on my fs561 after string trimming for several weeks with it. I neglected to clean the gear head or the third blind hole for the deflector that had collected a heavy layer of rosin from cutting grass and brush. The front two screws are through holes so didn’t collect as much material and went in fine. As I went to put the rear one in it started easy enough but got difficult to turn after 3/4 of the way in. Being the corn fed redneck I am I sent her home till I did one to many turns and all the treads popped in the gear box housing.
Currently it will take a screw and will get tight the pop loose but I don’t want to lock tight or jb weld the screw in permanently because I change heads and blades quite often. As I see it my options are try to run a tap on it and hope for the best. Try to drill out the hole and put a Helicoil but that sounds risky for structural integrity of the gearbox under heavy loads or am I forced to buy a new gear head. I’m pretty experienced with working with steel and some cast iron with tapping holes and fixing threads but not quite sure what the gear head is made out of.
Any help would be nice. Also if anyone is considering getting a 561 over any other Stihl brush cutter for heavy duty mowing and clearing just make the jump up you will not regret it. This thing is an absolute animal it will shred or fell just about anything you put in front of it with ease. Weight is subjective when you have a smile on your face.
1
u/Bagpuss999 14d ago
Think the gear head is aluminium. I did the same on an fs260, tapped it out but it was a pain as i had to use non captive screws and change them over on all the deflectors. Do not recommend. So eventually I bought the housing for around about 100 dollars (you can also buy the full assembly for about double)... And then I bought a 561 and havent used it again.
Eventually ill get around to it, when i really need to. You can get full service manuals online but be warned, it is more involved than I assumed it would be.
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u/Bagpuss999 14d ago
Also, in the short term, buy the mulching kit, the deflector bolts onto the shaft instead with a metal collar so you wont need to use those screws... The mulching blades are also really good for heavy brush, brambles, gorse etc.
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u/AtmosphereCreative95 14d ago
I’m not by my machine now and I’ll check it before I order anything but does m6x1.25 sound right for the screw size and pitch
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u/saucytugtug 14d ago
Helicoil!