# How to stop shaft from spinning when replacing bump knob on murray weedeater (video).



## tireshark (Aug 17, 2014)

Friend has a murray m2500 weedeater and he lost the bump knob. I went to HD and got a replacement for $10, but when i screw it on, the entire shaft starts rotating, which wont let it screw all the way down. 

Is there a way to stop the shaft from spinning while i am removing/installing the bump knob to add string? I have to pull the arm apart and jam a screwdriver into the other end of the shaft to stop it from rotating while i screw the knob on. Surely there is a better way to do it? 

Video:


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## lenaitch (Feb 10, 2014)

It should normally spin on fairly easily so I am guessing it is a 'universal' part and does not match the thread type or diameter of the shaft. Since it is 'plastic' and you've to jam it on by freezing the shaft, I'm guessing you've pooched the threads. Find the model number and get an actual Murray part either online or a dealer.


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## tireshark (Aug 17, 2014)

Thanks. I figured out what the problem was... the large part of the head has a hex shaped hole that is supposed to lock the shaft in place while you unscrew the bump knob, but the plastic had worn down so it would no longer grip the hex head of the shaft to keep it from moving.


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