How the heck do you guys torque a cylinder nut to 600 ft lb? Rebuilding Bobcat combo bucket cylinder.

[Semper Paratus]

Years ago we used to use "Turn of the nut" and a slugging wrench on metal to metal steam joins torque to 2000 ft-lbs+ to obtain a nominal 2/3 yield. If you new the grip length, fastener diameter and thread pitch you went into the tables and found out what angle of advance (number of flats) you needed after an achievable initial torque like 200 ft-lbs. So long as we got all the fasteners tight, in a couple of increments, in a Kriss cross pattern it worked well. Problems if you took it to full torque sequentially around the bolt circle.

 

[mo1]

I am putting new seals in and apparently I need to get the bottom nut to 600 ft lb. I do not have that kind of torque wrench. How do most people achieve this? Thanks.

Torque multiplier and a torque wrench that will go to 600 ft/lb divided by the multiplication ratio of the torque multiplier. I had to torque a nut on my rotary mower about 650 ft-lb and this was very easy to do with a 3:1 torque multiplier and a 4 foot long 3/4" torque wrench that goes up to 450 ft-lb. I set the wrench to 1/3 of what the required nut torque was and tightened until it clicked. The added bonus of a torque multiplier is that the handle on the multiplier (slip a piece of pipe over it and wedge it against something) takes the counteracting torque so I didn't have to try to jam something in the blades to keep the pan from turning as I torqued the nut as I would if I was just using the torque wrench by itself. Probably the worst thing was finding the correct size metric socket for the nut.

 

[4570Man]

Well, I will have to do more homework. My manual for my bobcat s150 has 600 ft lb for the lift cylinder and only 100 for the plate tilt and 90 ft lb for the bobtach wedges. So.... I need to find the proper torque for the bobcat combo bucket. My guess is it is below 600.

600 pounds sounds pretty high for a nut that size.

 

[CalG]

If I recall correctly, and have done the maths. correctly..

600 pound feet requires a 30 inch long , 3/4 " drive breaker bar and a two foot length of water pipe over the handle.
Three "ugga uggas" and a grunt is the EXACT the conversion equivalent.

 

[IndyJay]

This is an application where you don't have to be dead nuts accurate. RickB's method will be fine.

I needed to set the bearing preload on the steering head bearings on a motorcycle. This required a spanner wrench which I had, but no way to use a torque wrench with it. So, I measured from the centerline of the spanner 6" and ground a groove. This held the hook of my fish scale. A pull of 3 lbs on the fish scale yielded the required 18 inch pounds of torque.

A little ingenuity and math will get the job done in many cases.

Agree. Often these specs are a very precise number for a ballpark requirement. Engineers are funny that way. But how else would you describe "really, really, tight without breaking or stripping anything"?

 

[clydesdale]

I understand. Where I am stuck is that there is a huge difference between 600 ft lb and 90 ft lb. I specialize in breaking sh*t. So, I would feel more comfortable if I could find the service manual. But, so far, no luck. I may have to call the Bobcat dealer. My guess is that they will just say make it tight.

 

[clydesdale]

Well, I just took the nut off and all I had to do was turn it with a regular ratchet. Not only that, I put almost no torque through it. It was "snugged" at best. Either that, or it loosened up. It took zero effort to remove the nut.

 

[WranglerX]

Well, I just took the nut off and all I had to do was turn it with a regular ratchet. Not only that, I put almost no torque through it. It was "snugged" at best. Either that, or it loosened up. It took zero effort to remove the nut.

Does it have a "O" ring seal?

 

[wdchyd]

Well, I just took the nut off and all I had to do was turn it with a regular ratchet. Not only that, I put almost no torque through it. It was "snugged" at best. Either that, or it loosened up. It took zero effort to remove the nut.

You did good to catch it before it backed off on its own. The 6’ of pipe and 100 lbs is the best way to retorque if no other means avail.

 

[Smily0]

I'm not sure if you are open to spending any money, but I bought a 3/4" digital torque adapter for this purpose. I knew my brush hog called for that level of torque, trailer lug nuts were 200, and the new gooseneck hitch I was installing on my truck needed 375. I would have probably settled for several ugga-duggas from my Milwaukee high torque 1/2" impact if it hadn't been for the Gooseneck hitch. That was the most important in my eyes, so I started looking and found this adapter. It may or may not be the most accurate item on the market, but I'm sure it was better than me guessing. For $80 or so, I haven't regretted it one bit, and have used it more than I expected.

 

[oceank]

I rent. Last time I rented it cost about $20/day, including the torque wrench and the socket. Nuts that require high torques are usually bigger, and I don't own sockets for those sizes either.

 

[Seabeckredneck]

Something that big, I use Star torque. Using a 3/4 or 1 inch drive rachet or breaker bar, get in a proper postition and just puuullllll until you see stars! That should be tight enough.
PS make sure you have something soft to land on incase the lights go out...

 

[Junbug1959]

Do we want to open the discussion on lubricated vs non lubricated surfaces and threads?

Yes let’s get in to it (KISS) keep it simple stupid .
generally torque values are specified with a value in non lubracated threads. If you use lubrication than subtract 30 % off of the specified value. Remember you not rebuilding twin turbo 1200 hp funny car

if need to reference the Millwrights handbook there is here is a ton of useful info in it

 

[BeezFun]

I'm not sure if you are open to spending any money, but I bought a 3/4" digital torque adapter for this purpose.

Didn't know these existed. I just bought a 3/8" torque wrench not long ago, would rather have had one of these. Less space in the tool box and easier to adapt to hard to reach areas.

 

[California]

I had a loader cylinder rebuilt at the hydraulics shop. $165 and it came back with pipe wrench scars on the end cap.

Next time one dribbled I bought HF's 36" iron pipe wrench and had to add 3 ft of cheater pipe to get the cylinder end cap off. Total project cost $10 for seals and $20 for the wrench.

 

[DieselBound]

And then there's torque-to-yield! (initial torque value and then a rotational distance specified in fractional turns)

High torque value? Crank the crap out of it, operate and re-check: if it is holding up then chances are it's tight enough to stay that way- most everything is subject to eventual loosening anyway, no matter if properly torqued; it's a matter of how LONG!

 

[JWR]

I first encountered 600 ft-lbs torque numbers on bush hog blade nuts. Those are big healthy nuts. I don't know the size of your head bolts/nuts but I'd be very careful there.
Seems to me the torque multiplier is the concensus right route. However, I think I would try a big assed air wrench that claims to give 750 ft-lbs. It probably really will do 600.
Test 1 or 2 by following the air wrench with a borrowed torque multiplier and see how far off you are. Once you get the right settings you should be able to do this stuff very quickly, repeatably, and plenty close enough for your purpose.

 

[wpmlbg]

Sure it's not inch-pounds?

 

[JWR]

Sure it's not inch-pounds?

I do not know about the OP topic (head bolt nuts?) but I know for sure the bush hog blade nuts are in the 600 (I think they were 625) foot pounds area, not inch pounds. I had a blade carrier come off of a JD MX6 rotary cutter a few years back and go sailing across the field. Put it back on and tightened it as much as I could with a long arm and a 1/2" socket set. A few days later it sailed across the field again. Once I looked up the torque I knew why !! [And the blade nuts were similar torque numbers. So are mine on a 7ft Bush Hog brand cutter.] In the Deere hog case I used a cheater pipe and promptly ruined a socket and arm. Then went to a 1" drive and did it. Lessons learned... Do not own a torque multiplier but was told by my friendly Deere dealer that is what they use.

The 600 ft-lbs sure sounds high for head bolts....ridiculously high actually.

 

[ding beep]

Three "ugga uggas" and a grunt is the EXACT the conversion equivalent.

LOL. If I only need 600# of torque, I just make sure to only use 2 fingers.
Don't want to over-tighten anything down there...
ding beep