I also use both, for all the same reasons previously given. However, I also have a 3/4 drive IR that I bought specifically to remove the front axel nut on my XKR and the rear hubs off my GT6. No battery powered tool I’m aware of can take its place.

 

I have an electric (corded) 3/4 impact. I got it for 1 specific job, to remove the lower shock bolt on an my F150, which is torqued to 300ft-lbs. Why a shock bolt needs that I could not tell you.

I was skeptical at first but having used it I would choose electric over air power if only because there is far less infrastructure needed. Just plug in and go. Almost all of my car work is done by hand with various breaker bars and torque ratchets. Even lug nuts I do this way, breaker to get them off and torque ratchet to put them on.

For lighter duty 1/4 drive work I have a Dewalt battery impact driver that is the go to tool. For cordless stuff I like Dewalt because you can actually repair and rebuild them. Parts are pretty well available and they have service stores for rebrushing motors, etc.

At this point the only thing I think I would choose air for is painting.

 

Ok, that's two mentions of 3/4 drive. Never needed any of the sized sockets that only come in 3/4 drive so never thought seriously about getting one that big. I don't generally work on trucks but I'm usually restoring something that hasn't been apart in 50 or 60 years. I try to remember to soak things in penetrating oil the weekend ahead and wire brush the exposed threads. Apply a little heat maybe if its safe to do so. But the pneumatic impacts almost invariably fail when the parts have so fused together over that much time. Maybe I need to go full Tim Taylor and get the Binford 5000! (finally got to use that emoticon)

 

And my 3/4 air powered IR is actually from HF. A friend of mine who’s also a Jaguar/GT6 guy was amazed at how fast it broke the rear hubs loose (an eternal problem for GT6/Spitfire owners). The 3/4 drive takes no prisoners. Of course, I rarely get to use it, but when it’s the right tool for the job, it’s a Godsend to have handy. As infrequently as it gets used, even a HF product will probably last one or two lifetimes. For guys who aren’t professionals, who genuinely need the durability of a Dewalt, Makita, Milwaukee, etc., I have to wonder just “how” much worse the HF stuff is when compared to Ryobi, Porter Cable, B&D, etc.

 

Both, of course.

Most useful compressed air tool: 1/2" Impact. The primary way to change wheels or break a stubborn bolt after a a Kroil soak.
Most useful lithium battery tool: Drill driver with clutch and quick change bits. Everything from decking to door panels.
Most important hand tool: Torque wrenches in 1/2 3/8 and 1/4 sizes.

Advice if buying air tools: I have the Harbor Fright stand up 5 HP 120PSI compressor and universal couplers on every tool. The pneumatic paint shaker is superior to anything electric.

Advice if buying cordless: Decide on a battery brand (mine are Ryobi but any that will stay in business) as that will commit you to buying only their stuff for the rest of eternity. The cordless leaf blower is what you need on the roof when clearing gutters. Maybe I'm lucky there is a Ryobi factory clearance outlet down the road.

Advice on hand tools: Put a card with the sizes of your missing sockets in your wallet, as odd sockets are typically on clearance at the big box stores.

 

Prior USAF fighter crew chief, 13 years industrial sales specializing in assembly solutions.

Battery v corded? Whatever suits you.

Impacts. They should only run in reverse.

Never use Impacts to assemble anything. Erratic torque scatter for impacts can be verified using a torque analyzer.

Pulse tools are a hybrid & somewhat repeatable & dampen torque reaction. However they must be set for a specific torque w/torque analyzer.

DC Electric tools are very repeatable & very expensive. However, battery DC Electric tools are somewhat affordable now if you own/use a torque analyzer to set up the tool (Tools do not run on DC power, discrete tool outputs are DC Electric).You still must manage torque reaction with a reaction stop for higher torque values.

Use hand tools & torque wrench. Always reset your torque wrench to 0 when finished. If you drop your torque wrench you should recalibrate it but if you own a torque analyzer you could verify torque.

Using a torque wrench to verify torque on an already fasted bolt does not verify torque.

To re-torque, use breaker bar to break the fastener lose first, then re-torque.

 

Sadly, after I've finished a task, I often think to myself "Wait a minute, did I do that one already? Did I miss one?" Is there another way to check? How do inspectors in a manufacturing plant do it?

 

Manufacturers use a variety of assembly techniques.
1. Head bolts, let’s say 26. A single machine containing 26 DC Electric spindles controlled by another DC Electric controller. The spindles descend & contact the bolts. They dwell, run down to a prescribed value, stop to slow the fasteners to stretch, increase to a higher value, stop to allow the fasteners to stretch, finally continue until all fasteners reach the desired value. One additional quality check is the angle. The engineer can program a max angle of rotation of the fasteners after achieving the final torque value. These machines are very expensive.

2. As less expensive solution is 1 DC Electric tool mounted on a smart arm. The arm joints have encoders & a screen attached for 5ge user. The screen displays a picture of the head & the sequence of the fasteners to follow. A single DC Electric tool descends over the correct fastener. Only then will the tool operate. You still need to manage reaction w/reaction bar or attritional socket welded on a bar so a previously fastened bolt absorbs the reaction.

I bought a boat w/a 6.2 Diesel engine. The owner replaced the head gasket, valves, guides etc ... before I accepted the boat. I had a 1,000 mile trip up the Mississippi. At the 25 hour Mark we needed to retorque the head. My friend who was with me (old B-52 Crew Chief) & I stopped one evening & following the pattern loosened the correct fasteners & using a torque wrench torque the bolts back to the lowest value of the prescribed tolerance. That was 2012. A few years & hours later this was repeated using a value in the middle of the specified range. Gasket holding today.

A word about holding the torque.
1 hand in the wrench
Pull slowly at a right angle
If your hand is below the torque wrench grip or half your hand is hanging off the end of the grip you will achieve different values. If you have a friend with a torque analyzer you will readily see the difference.

 

Thanks to Fsarcone for his expert opinion. Very useful statements of best practice. Now I want to go get a torque tester. How come these rigs are so damn expensive? Although we get what we pay for, is there such a thing as an inexpensive or approximate torque tester?

McMaster torque tester $677.00

 

I guess most everything today is robotic. I'm just thinking in terms of the manual assembly of classic cars that I usually work on. There's sometimes a grease pencil mark or a messy daub of paint on a part indicating that an inspector checked it as it went down the assembly line. I've tried to reproduce those inspection marks, in one case using compressed air to blow the drip UP because the chassis would have been upside down at that point in the assembly process. I just always assumed that those assembly line inspections involved somehow making sure critical nuts and bolts were torqued properly. Surely those inspectors did something more than just eyeball it.

 

I got new DeWalt 20v Li-ion “Atomic” brushless driver and impact at Xmas. Loving them. Because of their size they fit into small spaces. They’re lighter than the 18v non-brushless units they replaced, so less fatigue when working overhead. They seem to have as least as much torque as the non-brushless full sized units they replaced. Speed control on them is excellent, even the impact driver has speed control thanks to the brushless motor.

I'm not going to use them on suspension work but like others have said, I do heavy work like that so infrequently that I am OK with hand tools for the heaviest jobs.