Question on using a torque wrench

[aircommuter]

Originally Posted by Nastynotchback1

Right tool for the right job. A left hand thread can be torqued because your just torquing the bolt. Your not breaking it loose. I'm not gonna take my 750.00 Snap-on to break bolts loose. It cost around 75.00 to have them calibrated. I will use my cheaper breaker bar.

I agree and I have the electronic Techangle Snap-On and it says right in the manual not for breaking fasteners loose. I wouldn’t use any decent torque wrench for that purpose, they are for the final stages of installation. Like I said before no real reason.

[DavidBo]

Originally Posted by rockfordroo

We had this discussion before. Click style in Navy aviation in 1971-1974, at least at my NAS.

We had all click-type wrenches at my base around that time, except for the huge b***ard we used for wing bolts. That was a beam style and took two people to use. Fun times if it slipped near max torque!
As far as loosening goes, we had to have acquire a special left hand torque wrench used only to check breakaway torque when loosening certain hardware. The difference was that the regular wrenches were calibrated in the tightening direction only. Apparently it was impossible to get a wrench calibrated in both directions, at least from the Navy labs.

[Curly2001]

I am sorry if this is a duplicate post but I don't see the one I just did. Just curious to see how many times you can torque a bolt? I have to lower my Curt hitch a hole and re-torque the bolts but don't want to have a problem. Didn't know if there is a rule of thumb on how many times you can torque a bolt before it becomes unusable. They only require 100 ft.lbs. of torque.
Thanks in advance,
Curly

[TitanMike]

Originally Posted by jeffnick

I personally torqued the new wheels to 110# and double checked them all before we hit the road. After about 50 miles I checked them again - several were loose. At 100 more miles I still found a couple that needed a little more oomph. The next 100 miles they were all snug.

This is not uncommon with cast aluminum wheels. Unlike steel wheels that usually have a "coined" center so the center can spring some as it's secured by the lug nuts, an aluminum wheel has to rely totally on tension in the stud to keep the lug nut tight. As the wheel heats/cools, it may cause some loosening and the tension in the stud is reduced. Subsequent re-torquing restores this as the wheels become more firmly seated.

In later years of aluminum wheel manufacture the back seating surface is cut with a slight bevel. This allows the center of the wheel to spring somewhat as nuts are torqued and the tension is both in the wheel itself and the stud.

Steel wheels with coined centers (it looks like a rib formed in the metal with the lug holes in the rib itself) don't tend to loosen like the early "spoked steel wheels" that had flat centers.

[DavidBo]

Originally Posted by Curly2001

I am sorry if this is a duplicate post but I don't see the one I just did. Just curious to see how many times you can torque a bolt? I have to lower my Curt hitch a hole and re-torque the bolts but don't want to have a problem. Didn't know if there is a rule of thumb on how many times you can torque a bolt before it becomes unusable. They only require 100 ft.lbs. of torque.
Thanks in advance,
Curly

There all bolts that have to be changed after one use, they are called "torque to yield" bolts and are commonly used on cylinder heads, engine internals and other high strength applications. They are tightened to a certain spec (often length, not torque), which causes them to stretch a precise amount and provide clamping force. Once tension is relieved that elasticity is gone and the bolt is scrap.
The standard hardware we typically use doesn't work that way, and it's OK to loosen and re-torque without concern (within reason of course, and without over-tightening). Think how many times a car's wheels get removed/installed in its lifetime, the studs are designed to take it.

[babock]

Originally Posted by aircommuter

I think the nut must be moving to get accurate torque after that checking torque can only tell you if is at correct torque or over, unless one wants to set the wrench slightly up each time until the friction can be overcome. Now you know it is over for sure and maybe it was correct before you started.

Agree 100%

cditorque.com

Only a small part of the torque applied to a fastener contributes to clamping force. The remaining, as much as 90% of the total applied torque, is used to overcome friction under the fastener head (or between nut and washer) and friction in thread engagement.

As far as storgae CDI reccomends:

Should always be stored at it’s lowest torque setting

[aircommuter]

Sometimes stretch bolts can be reused if the manufacturer gives a diameter limit for the stretch area. Then a micrometer would be used to check it prior to reuse.
Personally I replace them every time.

[Wishart]

I deliver travel trailers and 5th wheels from Elkhart County Indiana to dealers across the United States and Canada. The problem that requires torquing is that lug nuts on aluminum wheels work themselves loose in the following circumstances:
- the lug nuts have been tightened for the first time when the wheel is new or
- the wheels has been removed to repair or change a tire
- the camper has sat unused for several months.

I was taught, and practice, the following every time I hook up a unit (including my own 5th wheel every spring):

1. set the wrench to 90 pounds
2. apply the torque wrench until it clicks - which usually happens immediately, because the lug nuts were tightened appropriately at the factory
3. stop in 30 - 50 miles and apply again.
4. do it again in 150 miles.

Assuming everything is tight I am fine.

I GOT IN TROUBLE ONCE WITH MY OWN TRAILER ON A 5000 MILE TRIP:
I had picked up a nail and had the tire repaired tire dealer. Said dealer torqued the nuts. I forgot to re-torque. Two day later the wheel came off.

I disagree with those who loosen the nuts first - torquing then is equivalent to the first torque. They are starting over every time.