I Need to Torque Something to 600 Ft-Lbs

But, my big torque wrench only goes to 250 Ft-Lbs.

A sufficient range torque wrench is pricey.

I was considering a torque multiplier for the job.  That combined with my big torque wrench should work.

Then I found a more affordable, plausible, option, in the form of a digital torque adapter.

I've got a 4' 3/4" drive breaker bar, so that combined with that digital torque adapter.

I'd likely get more use out of the multiplier for future projects, but I'm not sure it out weights the cost savings, I do already have that big breaker bar, and an acetylene torch, so, I can generally persuade things loose and/or destroy them already.

Thoughts?

Do you weigh 200 lbs?

Do you have a 3 foot breaker bar (or one you can hang off of at 3 ft)?

If yes, problem solved (which may need some minor adjustments depending on your weight).

bigdaddylee82 said:

But, my big torque wrench only goes to 250 Ft-Lbs.

A sufficient range torque wrench is pricey.

I was considering a torque multiplier for the job.  That combined with my big torque wrench should work.

All I know is that I need one of these. Do they work in reverse or just for tightening?

In reply to aircooled :

Torquing in situ will be perpendicular to gravity, so I can't hang or stand on anything to turn it.

I had a hitch ball that needed something like 500 ftlb. I bought the socket, 3/4 breaker, and in my flip flops in the middle of our cul de sac, put an 8 ft tube of 4130 on the end of that breaker and in a leisurely manner, snugged that motherberkeleyer up to gutentieight

wearymicrobe said:

All I know is that I need one of these. Do they work in reverse or just for tightening?

It's a planetary gear set, it's directionally agnostic.

When I had to do the kingpins on the K30 they supposedly are torqued to 600 ft/lbs. It took everything I had on a 6 foot pipe over the 3/4 inch breaker bar to break it loose. 

Damn and here I thought it was a rotary flywheel nut...

Someone may have figured out an angle torque spec.

For example, the Mazda rotary flywheel nut is supposed to be torqued to 290-360ft-lb.  Someone a long ways back worked out that torque was 150ft-lb plus 120 degrees.  Torque to 150 with a common 1/2" torque wrench, and then turn the nut 2 more points with your 8' cheater on a 3/4" breaker bar.

Alternatively, rattle it with a 3/4" impact gun until it stops turning.

Stampie is on the right track, W250 kingpins.

I'm sure breaking them loose will be a chore, but I'm more concerned about getting the new ones torqued appropriately.  What did you torque yours with Stampie?

$80 isn't much, but I'd probably look around to see if I could somehow rent or borrow one.  How often do you need to do this?

bigdaddylee82 said:

In reply to aircooled :

Torquing in situ will be perpendicular to gravity, so I can't hang or stand on anything to turn it.

24 foot bar and a fishing scale that goes to 25lbs?

Extreme example, but something similar could be done.  My concern would be that there will be some drag on the threads and the surface to lessen the amount of torque.

3/4 drive Torque adapter probably wouldn't get as much use as a torque multiplier assuming the multiplier was 1/2".  I've read that the mechanical limits of a 1/2" square of tool steel is about 1000ftlb so a quality multiplier in 1/2 should get it done. 

Having said that, if it was me i'd probably do the rough math based on my weight and a cheater pipe. Remember, it can be LONGER than you need it to be as long as you're only holding it at the proper distance. 

bigdaddylee82 said:

Stampie is on the right track, W250 kingpins.

 

I'm sure breaking them loose will be a chore, but I'm more concerned about getting the new ones torqued appropriately.  What did you torque yours with Stampie?

Same 3/4 inch breaker bar with a 6 foot pipe. Got it as berking tight as I could. 

If you were near me I have a 1" torque wrench I'd loan you for semi lug nuts that goes to 750. Semi lug nuts torque at 475.

Building on what chandler said. Look for someone who services heavy equipment in your area. Lots of things are crazy torque values. Most mobile service trucks will have a 1" torque wrench that can go that high. May be able to get someone to swing by and let you rent it for a few minutes.

The auto parts stores "rent for free" Torque wrenches.

I'm not sure if they have the big dogs or not.  Might be worth checking for the one time use. 

bigdaddylee82 said:

wearymicrobe said:

All I know is that I need one of these. Do they work in reverse or just for tightening?

It's a planetary gear set, it's directionally agnostic.

 

I'm going to do my damndest to work "directionally agnostic" into my next conversation at a party

I worked for an oi company many years ago and I remember watching some repairmen have to torque some nuts to 2000 lb/ft using a tool with a 10 ft lever!

Mr_Asa said:

Extreme example, but something similar could be done.  My concern would be that there will be some drag on the threads and the surface to lessen the amount of torque.

The amount of friction in the threads doesn't change based on the lever arm length.  It does change based on the total torque, but it doesn't matter how long the lever arm you use is so long as the length*force value stays the same.

A torque multiplier does introduce new friction with the internal planetary gears, but presumably that's either small or compensated for in the design.

I have the 60:1 lugbuster used on semi trucks to remove Moby's wheels if ever that's required. An item bought very much in the fire extinguisher philosophy...

What is it?  How specific is the 600 ft/lbs?  I ask because how much accuracy do you really need?

Can you get to both sides of the bolt?  You may be able to calculate stretch instead.  

I have a hard time believing anything legitimately was engineered to "600 ft-lbs". I'd buy 573 or 604 or some other number but 600 is like they calculated a number and the said..  600 is good.  

codrus said:

A torque multiplier does introduce new friction with the internal planetary gears, but presumably that's either small or compensated for in the design.

 

That Neiko brand one is 3:1, but has a chart to compensate, you set your torque wrench something like, desired torque divided by 3 plus 10% so to get 600 Ft-Lbs through the multiplier, I'd set my torque wrench at 220 Ft-Lbs.

nocones said:

What is it?  How specific is the 600 ft/lbs?  I ask because how much accuracy do you really need?

Steering kingpins on a Dana 60 under a 3/4 ton Cummins powered old Dodge.

I watched some youtube videos where folks seemed satisfied with Loctite and a long cheater pipe, turn just short of hernia and call it good.  I'd like to be a little more accurate than that.

In reply to bigdaddylee82 :

On mine I had one of the plastic cups that was cracked.  I could have probably just replaced it and been good but went ahead and did the kingpins because hell I was already there..

Knurled has the ticket.

Torque spec is just a stab at about how much torque you have to apply to get the fastener to stretch the perfect amount.  It is a bit arbitrary, actually... especially at 600 lb-ft.  One burr in a thread, or the existence of a tiny speck of rust (or grease) can mean that 600 lb-ft could have a wide range of actual stretch.  This is why the torque-angle method was developed.  Torquing something to 100 lb-ft has a very good chance of being pretty accurate, then the angle provides a known stretch value because the thread pitch is known.

If you really need to do it to 600 lbft, I would think a 3' breaker bar and you pushing with an analog bath scale should do the trick.  Stop when it reaches 200 lbs.  If you can't push that hard, try a 4' breaker bar and push until 150 lbs.  5' = 120 lbs, 6' = 100 lbs... etc.