Home › Forum › Ask A Member › OMC vs HF flywheel puller › Re: OMC vs HF flywheel puller
The biggest advantage of the shoulder screws over the grade 8 hex heads is the shoulder screws square themselves to the surface when the shoulder is tightened firmly against the top of the flywheel. The distance between the shoulder and the head is also a held dimension on shoulder screws. That means when everything is tight it takes as much error out of the setup being square as possible with the least amount of effort.
Pulling any of the screws at an angle concentrates the load on one side of one of the threaded portions of the screws. That is want causes them to break.
Heavy hard washers are intended to support heavy loads without distorting. The thickness of them is a lot more consistent than your typical grade 8 hardware store washer too. The biggest problem with them is they just are not heavy of hard enough. They may work OK most of the time, but with as much force as this operation is requiring the heavy hard washers would be a much better option. I hope this helps explain the advantage of the shoulder screws in the puller.
-Ben
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