My ThurenFab TB has held great. Do remeber it has to be tightened ALOT.... and I mean alot, as noted in the directions....

 

My guess would be frequency. The same reason our 4BT could destroy a clutch in it stock 110 HP form. The freq of the power pulses shattered the dampening springs. Same reason your hands go numb when something shakes enough. You have plenty of strength to hold, just can't handle the freq.

Randy

 

The only explanation for your brush hog bolt failing, is that the Grade 8 bolts you used were off spec dramatically.. Depending on where you got the bolts, and where the store actually got the bolts, there is a very good chance they were Chinese and remember, Chinese bolt markings mean nothing other than that... markings... there is no enforcable standard for those chinese parts sold here. This is a large and growing problem, now that we have been told we need to be globalized and not to worry that we are supporting communist empires.....

That's why there are such strict rules on tracability for aircraft fasteners...


OR another reason, is that you finally started avoiding all the un-mowable obsticles with the mower .



KP

 

Good to know.. I was told repeatedly how that was the last time you would touch the device and how the 03TBK was the bad actor.

I was be-littled for my purchase. Hindsight, I like my wrenches being used on other mods.

 

you're talking about the bushing end, right?? i'd use a metal lock nut or cotter pin for that kind of application where there's possible rotating of the bolt. loctite would be worth a try though.
if it's a grade 5 bolt you can drill your own cotter pin hole

ditto about the source on hardware. we even have to pay attention where we get aircraft hardware from because some companies advertise their stuff as legal but if you read the fine print it's not...i can't even imagine what the grade quality actually is at the hardware store!

harmonics/vibration frequency have a LOT to do with fatigue/failure of any form of metal, we run into that all the time with aircraft.

 

I think what he's saying is that on the initial tightening it has to be torqued to a very high number. Not that it needs to be tightened often.

 

ok this was the frame end where the heim type joint is used....not sure what its called.

anyway i lossened it tongiht and put loctite on it then tightened it as tight as two pretty strong guys could pull the breaker bar and then i check it and everything seems tight...so now i wait and see if it loosens again or if my problem is that the bolt may be a weak grade and stretching over time.

 

oh, got it. i was thinkin other end. do you have more than 1 or 2 threads through the nylon? the loctite should work, if not go get a metal lock nut that has the end kinda crimped, that will not come loose...only way those will loosen is if you take it on/off a lot.

 

from the website:
13. Now it's time to torque down the track bar. Being that the threads are greased the
torque values are decreased making it easier to get everything tight. The axle end
bolt is VERY prone to not being tight enough but with greased threads,get the bolt
about 100-120ft/lbs. This will keep the axle from shifting and popping. The large bolt
at the upper frame end needs to be torqued to a crazy 300ft/lbs EVEN WITH
GREASED THREADS!!! I usually put a short pipe on the breaker bar/nut and go to what
"feels" like 150ft/lbs if you were not using a pipe. It would be a good idea to get an
actual 300ft/lb torque, on the bolt, if you can find someone with a torque wrench
that actually goes that high....

 

I use a grade 8 in my brush hog because the grade 5 kept wearing and or shearing. The grade 8 will wear and break very rarely but it sure is better than changing several a day. Here in WV we mow pastures and such that are riddled with rocks trees and brush. The brush hog grinds up everything. That's my experience with the bolts.

 

A few months ago, a guy on the pirate 4x4 board tested some Home Depot grade 8 fasteners and they passed the tests.. not by much, but they were up to spec.. Just FWIW..

My local TrueValue hardware store has good quality hardware, and it's where I go if I can't get to Fastenal..