Torque on a Bush Hog.

[brentbx22]

I'm rebulding a Bush Hog and I want to know how do you torque the big 1 13/16' castle nut that holds the main blade bar to the gear box shaft? It needs to be at 450'#, but I don't have a torque wrench that goes over 250'# for one, nor do I thing I could hold the thing to pull it that tight. Should I use a impact wrench, braker bar with a cheeter pipe, or break down and get the right torque wrench?

 

[Bird]

I guess the only "right" way is to break down and get the right torque wrench, so I certainly ain't gonna recommend to anyone that they do it any other way than the way the manufacturer recommends.

But of course, for me personally, I just put them on with my impact wrench rated at 425#. /forums/images/graemlins/wink.gif

 

[slowrev]

I am like Bird on this one.
However one point or two. Woods brand brush cutters require you to use locktite on this shaft, otherwise wobble will ruin the blade carrier. Seen it happen. Also on the woods brand you have to use the correct amount of spacers as this nut and blade carrier adjusts the preload on the bearing. Not sure if this is the case on Brush Hog brand or not. Parts for these things are not cheap, check and do it right. Also a blade carrier will travel quite a ways if it comes off !!!! I know someone this happened to.

 

[brentbx22]

Bush Hog says nothing about locktite, but there is a Cotter pin and i'm thinking (maybe wrong) the book says to torque to 450'# and if the slots on the nut don't line up to back the nut off till they do, does this tell me it needs to be tight but does not have to be right on 450? I will try to borrow a torque wrench but may not be able to find one, i'm scared to ask but does anyone know how much a torque wrench 3/4 drive to go up to 450 cost?

 

[boustany]

I think that I saw a trick used once where if you extend the torque wrench with a pipe, for example, to double its length, then the actual torque is double what it reads. Maybe I'm hallucinating. It happens.

Failing that, your you tighten the nut until it cracks, then back off a bit because you've gone too far ....

Or go to 250 and use Locktite. Or rent a bigger one.

 

[Glenn9643]

When I was in the Army I pulled a stint as S4 sergeant in a forward support battalion. One of our units was a direct support maintenance company (for a tank brigade). They had torque multipliers and I believe the brand was "powerdyne". Have no idea of the cost of these things or where you might find one.
I have a Bushhog 286 and the castle nut you're referring to loosened a little last year. Mechanics at the dealer told me that it was a tapered shaft holding the blade disk. I used a 3/4" pullhandle with a five-foot cheater bar to "torque" mine.

 

[Bird]

</font><font color="blue" class="small">( extend the torque wrench with a pipe, for example, to double its length, then the actual torque is double what it reads )</font>

I don't think so. /forums/images/graemlins/wink.gif I imagine what you have in mind is the torque multiplier that Glenn mentioned. I've never checked to see if places like Harbor Freight, Sears, etc. have them, although they probably do, but I know the tool trucks like Mac, Matco, and Snap-On carry them.

 

[Solo]

Brent
A good one will run around $600 you can get a cheap one from Harbor Freight for $150. You get what you pay for. Try to rent, one my local rental yard has one, for $35 a day.
Solo

 

[BillyP]

Cheater pipe.

 

[Zork]

"I think that I saw a trick used once where if you extend the torque wrench with a pipe, for example, to double its length, then the actual torque is double what it reads. Maybe I'm hallucinating. It happens."

No, actually if you the lengthen the handle you will decrease the amount of psi reguired to apply whatever torque the wrench is set at. You can buy an air wrench that will deliver that amount of torque, but you'll really not know how much your applying. A torque wrench from all ranges up to 1100lbs can be purchased from Mountz, Inc.

ISO 9001 Company

Phone:408-292-2214

at www.etorque.com Hope this helps you. /forums/images/graemlins/grin.gif

 

[AndyMA]

</font><font color="blue" class="small">(
No, actually if you the lengthen the handle you will decrease the amount of psi required to apply whatever torque the wrench is set at. )</font>

One way to do it if you're only doing it once in a while is to extend any wrench with a piece of pipe and then connect a pull type scale to the end of the pipe. Apply your force to the other end of the scale. For example if you are using a 5' pipe, to apply 450 ft lbs of torque you would need to apply 450/5 = 90 lbs of force on the scale. Just remember that the actual length of the pipe is determined from the center of the nut to the point where the scale exerts it's force. (and the scale pull needs to be perpendicular to the pipe) This method will provide a measurement of torque that is actually more accurate than most torque wrenches. Also make sure you lubricate the nut before you torque it or a major portion of what you are measuring will be friction, not the actual torque required to produce the required stretch in the bolt.

Andy

 

[brentbx22]

Franz I called Mountz thanks for the link, they only have one wrench that goes from 120# to 600# and the cost is $715.00 + shipping, /forums/images/graemlins/shocked.gif /forums/images/graemlins/shocked.gif
This Hog only cost me $300.00 used and another $250.00 in parts and labor to replace all the seals and bearings, just brought the gearbox to the shop so I'm putting it back on this weekend.
Andy that is a neat way never heard of that, I think i'm going the impact wrench rout.
I will let everyone know if it stays on, if it comes off you may never hear from me again. /forums/images/graemlins/frown.gif

 

[Bird]

Brent, since it's a castle nut and you put a cotter pin through it, and the impact will get it pretty tight, I wouldn't worry about it.

 

[brentbx22]

Thanks Bird, that's what I think also just nice to get a 2nd opinion.

Why did you move back to town?

 

[Bird]

</font><font color="blue" class="small">( Why did you move back to town? )</font>

Not by choice. /forums/images/graemlins/wink.gif I'd much rather still be out in the country, but family members needed my assistance and I had to get back close to help them. But it's not too bad. /forums/images/graemlins/wink.gif /forums/images/graemlins/laugh.gif