Tiller Sheared tine bolts on my new KKII tiller......

milkman636 · May 28, 2012

Something happpened yesterday that I don't remember reading about on here.

While tilling an area to plant some sweet corn I found a big rock about 5-6" down. It is an area that had broccoli planted last year, so it should have been easy tilling. On the second to last pass the tiller started bouncing and left about a funny looking spot in the finished till. When I got to the end of the row I stopped and checked everything out.

Looking under the tiller I saw that tines on two adjacent flanges in the middle were kicked backwards out of alingment and missing the leading bolt on the flange. Luckily the other bolt held on each one. So I went back to the funny looking spot and started diggin down by hand. When I had a big enough rock top exposed to stand on it with both feet, and also found one of my broken off bolt halves with the nut still on it, I stopped digging.

After reading about how these tillers just "walk up over rocks" I was suprised at having any damage. Two of my tine bolt sheared and I also found a raised dent in the top of the tiller where a rock hit on its way up out of the ground. The tines look like they survived fine, but I still was expecting any repairs in my first year of tiller ownership.

So is a tine bolt shearing just a normal experience for any of you that have some rocky remnants in your ground?

Baby Grand · May 28, 2012

I think it depends on the shape, depth, size and type of rock you hit as well as forward speed and PTO speed. I hit a big rock yesterday - about 20 x 8 x 12 inches. It was down about 5" under the surface. It made a heck of a whump and bounced the tiller (and me) pretty hard. Didn't do any damage, which really surprised me. The fact that you lost the bolts, but didn't bust a tine or something more expensive, suggests to me that either the bolt torques need to be checked, or that is one stout tiller.

Loose bolts make for weak joints, so you might want to loosen a few and see if any are marginally tight. It's not a trivial job. You really need to power wash the working bits until everything is squeaky clean, then take a breaker bar to those nuts (hold the bolt; turn the nut).

bigtiller · May 28, 2012

Breaking bolts, tines and even chains seams to happen with some regularity to some of the less expensive tillers. I'm just going by what I've read here. The only tillers I have owned for the last 20 years were a JD 450 and a Land Pride RTR1050. They were NOT inexpensive! Nothing ever broke on them but I did wear out 2 sets of tines on the JD in the 13 years I had it.

dex3361 · May 28, 2012

Most of the KK tillers are great tillers and come with slip clutches. I suspect the slip clutch is either to tight or is seized and needs slipped to clean it up.

I have pulled up some big rocks with my KK tiller with no issues.

milkman636 · May 28, 2012

I agree with you Baby Grand about checking bolt torque. Being brand new I figured the bolts would've been torqued correctly at the factory. Maybe not?

A long time ago I learned that extreme overtorqing can also cause bolt failures. One of my meat-headed high school friends couldn't figure out why wheel studs kept snapping off on his truck until someone introduced him to a torque wrench. Problem solved. Either way I'll be checking them all after I find a spec.

The cluch is set according to the book from KK. I am guessing this rock is at least as big as large watermelon. I was at full pto speed going slow in low range and caught the top of it with the center two tines. I think those two tines hitting the rock are what bounced the 715# tiller up out of the ground.

I guess when 715 lbs. starts bouncing a couple bolts breaking is probably best case scenario. It might be worth a try to back the tension off slightly on the clutch bolts. I'll have to think about that some more.