Can I torque loader bolts with impact wrench?

[Laffyridge]

Hey folks any help/advice appreciated! Just bought a Mahindra 3616 and have a little more than 10 hours on it. According to manual I need to re-torque loader and frame bolts to spec. Can I use my pneumatic impact wrench or do I need to spend more money and buy a torque wrench?

 

[ovrszd]

I'm not a big torque guy. I tend to tighten by feel.

You're air impact will have a maximum amount it will generate but the varieties in that are so great you won't get within 50 ft/lb of accurate. If you are truly concerned about torque values, get a wrench. O'Reilly's and I'm sure other parts stores will lend/rent you a wrench for a day so you don't hafta buy one.

 

[Gary Fowler]

I'm not a big torque guy. I tend to tighten by feel.

You're air impact will have a maximum amount it will generate but the varieties in that are so great you won't get within 50 ft/lb of accurate. If you are truly concerned about torque values, get a wrench. O'Reilly's and I'm sure other parts stores will lend/rent you a wrench for a day so you don't hafta buy one.

Unless you have a Skidmore device that you can measure the tension that your impact puts out, it would be just guess work. Depending on size of your impact, it could over tighten the bolts and that could cause them to snap. I like the AISC method (turn of the nut) and never use a torque wrench. Torque measurement is too dependent on friction modifiers to have any degree of accuracy. Turn of the nut assures that you have stretched the bolt but not overtensioned it. Usually this would be about 1/4 turn past snug tight with snug being after all the slack in the joint is taken out and the bolt is tight between all surfaces. Then mark it and turn it another 1/4 to 1/2 turn depending on the length of the bolt OR just tighten it by feel as OVRSD says, but that does take some experience to know when each size is tight but not too tight. ON my LS all the FEL bolts are so large (about 1" diameter)that I use an end wrench or socket with breaker bar and tighten them as much as I can and that has to be tight enough.

 

[eddie48]

On the larger bolts like that, in that kind of application, I tighten them as tight as I can and then turn another 1/4 turn.

 

[RickB]

I'm not a big torque guy. I tend to tighten by feel.

You're air impact will have a maximum amount it will generate but the varieties in that are so great you won't get within 50 ft/lb of accurate. If you are truly concerned about torque values, get a wrench. O'Reilly's and I'm sure other parts stores will lend/rent you a wrench for a day so you don't hafta buy one.

Tightening "by feel" is more accurate than using an impact. Some hardware is put in more peril by overtorquing than under.

 

[RickB]

On the larger bolts like that, in that kind of application, I tighten them as tight as I can and then turn another 1/4 turn.

Only slightly better than tightening until they snap, then backing off 1/2 turn.

 

[George2615]

I agree with Richard. Rent a torque wrench for the day from auto parts store. The impact gun isn't exact. It may tighten them but they may not be the proper torque, too little, or too much and could snap the bolts.

 

[Laffyridge]

Thanks all of you guys for the advice very helpful! Finally found my 1/2 " drive today and was able to tighten the bolts down by feel...will re-check them after another 10 hours and see if there has been any movement but I wrenched them pretty good!

 

[tcartwri]

I have always found that box wrenches are the length they are so that you can apply the right amount of torque for the fastener. ie; a half inch wrench is usually about 7" long, which when pulled with a decent amount of force results in about the correct torque..... for a quality fastener.

If you ever find a bolt that just wont offer that feel through the wrench, stop, because it is stretching and about to snap.

 

[oliver28472]

I had a remanufactured 302 put in my 81 F-150. The shop used an impact wrench to tighten the Grade 8 bolt that holds the harmonic balancer on the front of the crankshaft. The bolt broke in less than a year. I was able to take a chisel and back out the remainder of the bolt. Put on a new balancer and torqued the new bolt in with no problems since 2003.