Replacing Spindles on RTZ-50 & Self-Tapping Screws

[ustmd]

So, I needed to replace the blades on my RTZ50 and decided since they had over 300 hours and I would do the spindles as well.

I order them off of AMAZON as well as 12 replacement self-tapping screws.

I must be installing them wrong. Using my impact driver, so far I have sheared two off before I had them seated and had one go so wonky on me that it cracked the spindle housing.

Any help or suggestions? I thought about tapping the holes, but that would defeat the purpose of the self-tapping screws.

 

[2ndhalf]

Self tapping screws are generally designed to go into somewhat thin metal. Not sure what gauge your trying to shoot them into but if it is pretty heavy guage steel you need a drill bit.

Also, not trying to tell you how to spend your money or time but replacing spindles at 300 hours that are working fine seems to be a waste of both. I have had spindles last well over 900 hours on lawn tractors not even commercial quality spindles.

 

[GBHRPS]

ustmd,

Retap all of the spindle mount holes that are still good (no broken bolt in them) and hand try screwing the bolts in first. Forget the impact gun when you install them.
Then drill out the broken bolts, meaning you'll need to redrill those holes larger and use larger and longer bolts that you can put a nut on top after they go through the spindle mount leg.

As for the cracked leg of the spindle, after its other three legs are secured to the deck, drill its hole larger, and install a longer, larger bolt that has a thick, large diameter washer on top before you put on a nut. The 3 correctly attached spindle arms should keep that cracked one with the large thick washer from moving.

Keep your old spindles for future repairs. Good Luck!

 

[xring100]

I agree with g8hrps you can not use an impact while trying to drive in self tapping screws in fresh metal. The screws need to be hardened to cut the metal they are trying to cut. Hardening makes them brittle and prone to snapping under impact loads. A drill would probably run them in fine.

 

[travlitt]

I see no reason to replace a spindle if it is not cracked. just replace the bearings. No need to remove the spindle to do the bearings.

 

[s219]

I wouldn't think an impact driver is the right tool for self-tappers -- use a drill instead.

 

[tomplum]

No, actually an impact wrench is what is used to install the proper screws in the spindle. Not a 1/4" driver, but an 1/2" impact. The question is if you have the proper screws. I use a lubricant as I drive them in - fluid film actually. That way there is a prayer to remove the hardware next time. Drive the first one just near tight, follow with the rest snugging them carefully as you go- by hand if you want. If you are using a spindle w/ a cracked leg- think about the best position in regards to belt tension and torque on the spindle. If you are still skidish, tap them through and lock washer them up or use blue loctite. As mentioned, you could reload the other housings on the deck. As you are likely finding out, the bolts snap easily when removing them.

 

[Bob_Bainbridge]

To install self-tapping screws the first time I think I would use the old-fashioned manual method with a socket and ratchet wrench. Power tools are not the best choice to cut new threads as you have already found out the hard way.

Bob B.