mower blade shaft re-thread.....help

[reynoldston]

Tapping to the next size does remove material, but that's why you use a bigger bolt. How does that make it weaker?

We aren't getting to the point where the wall behind the threads is getting too thin. I don't think there is any concern about removing material. And tapping to the next size or two is barely any difference at all...

Thread #6 the OP said he used a 3/8 -24 tap and die. You will find that is the original size not oversize. If the threads were bad then he would be removing metal. Not that it matters to me, I wouldn't feel a thing if the blade comes off and hits someone. I suggested he makes sure he tightens the bolt to specs.

 

[Fish]

Putting in a helicoil would require removing metal, in order to accommodate the insert, but you still use the original fastener, and is a great repair, stronger than the
original. Also, going to a larger bolt might mean you have to enlarge the blade hole as well..

 

[reynoldston]

Putting in a helicoil would require removing metal, in order to accommodate the insert, but you still use the original fastener, and is a great repair, stronger than the
original. Also, going to a larger bolt might mean you have to enlarge the blade hole as well..

Yes, yes and yes :thumbsup:

 

[motoman]

Good advice IMO. If a "clean out" was done on buggered threads a good test is to torgue the bolt to the upper range of the scheduled value (torque) with a torque wrench. Bad threads will not allow that value to be reached and the force will pull out threads . Then oversize or helicoil. Better that than risk runaway windmill. :2cents:

edit, threads steel/steel