Bush Hog Blades

Turbys_1700 · Sep 19, 2013

Several weeks ago I replaced 4 blades on our 10' Howse Rotary Cutter...
The old bolts that attached the blades to the stump jumper utilized a lock washer to tighten the bolts...
I went ahead and purchased 4 new bolts with the blades and low and behold, the new bolts have castle nuts with carter pins for securing the blades...
I do have a problem though...
As tight as I can get the bolts, only 1/2 of a hole is showing through the bolt for the carter pin...
My only solution that I can see is to take the stump jumper off and grind down the stump jumper attachment bars...
That would give me enough tolerance to put in the carter pins...
I am thinking that my easiest option would be to utilize lock washers on the new bolts and call it a day...
Any input and thoughts would be appreciated...

SoGeorgia · Sep 19, 2013

Turbys_1700 said:
Several weeks ago I replaced 4 blades on our 10' Howse Rotary Cutter...
The old bolts that attached the blades to the stump jumper utilized a lock washer to tighten the bolts...
I went ahead and purchased 4 new bolts with the blades and low and behold, the new bolts have castle nuts with carter pins for securing the blades...
I do have a problem though...
As tight as I can get the bolts, only 1/2 of a hole is showing through the bolt for the carter pin...
My only solution that I can see is to take the stump jumper off and grind down the stump jumper attachment bars...
That would give me enough tolerance to put in the carter pins...
I am thinking that my easiest option would be to utilize lock washers on the new bolts and call it a day...
Any input and thoughts would be appreciated...

Yeah.. If you never had a problem before just using lock washers I say just get some washers and crank them down tight.. I also use loctite but that's just the way I do it.

LD1 · Sep 19, 2013

It would be easier to either shave a bit off the nut, or take a little air cut-off tool and cut down a bit of the castle's that's blocking the hole.

Few other suggestions...how tight is "as tight as I can get"??? And was that dry?? if so, add a little never seize or oil and try again. May get just enough.

Also, perhaps try re-arranging nuts and bolts around. Different combinations may be machined slightly different.

SPYDERLK · Sep 19, 2013

Find a nail that will almost fit thru the available open hole. Tap it thru.

Turbys_1700 · Sep 19, 2013

Thanks for the help guys...
I am torquing those puppies down with a 3/4" drive air impact wrench rated @ 950 ft.lb...
After that I am putting a 20" long 3/4" drive breaker bar with a 36" pipe attached for leverage...
The bolts are tight as can be after the air impact and If I was to put any additional pressure on the breaker bar I could easily demolish it...
I pull down on it until I feel the breaker bar start to give...
I believe that my impact is delivering very close to 950# of torque...

LD1 · Sep 19, 2013

It is possible you are over torquing them.

The bolts on my bushhog 306 (which takes a 1-11/16" socket) only have a torque spec of 450 ft-lbs.

I am guessing 950 is a tad much.

IF you have a way to measure (or guesstimate closely), use your breaker bar and cheater pipe and only apply about 100-120# of force at a distance of 48" from the center of the socket head. That should get you over 400#. and with a castle nut, that should be more than enough.

mikehaugen · Sep 19, 2013

Are you using the lock washer still?

Dumb question maybe, but I had to ask.

...Also, they are cotter pins. Not that it matters though.

gunmonkeyintl · Sep 19, 2013

Turbys_1700 said:
Thanks for the help guys...
I am torquing those puppies down with a 3/4" drive air impact wrench rated @ 950 ft.lb...
After that I am putting a 20" long 3/4" drive breaker bar with a 36" pipe attached for leverage...
The bolts are tight as can be after the air impact and If I was to put any additional pressure on the breaker bar I could easily demolish it...
I pull down on it until I feel the breaker bar start to give...
I believe that my impact is delivering very close to 950# of torque...

Pardon my shock/ignorance, but WTF did you come up with that procedure?
You have a driver that provides a (somewhat) known torque, and then you go to a breaker bar and wait for it to "start to give" - what exactly does that feel like, anyway?

I'd check your torque specs in the manual (or a standard chart for your hardware size) and roll with that. 950 seems way high for an application like that. $0.02

mikehaugen · Sep 19, 2013

I think he was just trying to demonstrate that he could not get them any tighter and it still wasn't tight enough to expose the hole. I think air tool ratings are pretty optimistic anyway, especially since they are usually reverse biased and apply way less torque in forward.

I would have to check, but aren't the blade bolts spec'd a lot lower than the center stump jumper bolt? I think that 450 figure is for the center bolt.