i've been playing with my cars a bit recently and i'm thinking about getting an air tool set. i've never used any of these before and i'm curious of their effectiveness. can these things really crank off all those rusty bolts? tell me how they've been to you. what they're capable of and your compressor setup.

~Dave

 

At home I have a 7 hp 60 gallon husky air comp. bought from home depot (a bit over kill unless you also paint or use sanders or air hammers with it). The higher the compacity in gallons the more force and less stain on the motor, you would need at least a 30 gallon tank. Buy a compressor based on the amount of cfm you plan on running (cfm rateings are usually on the boxes the tools come in). I have air guns, ratchets, air hammers, nail guns, staplers,sanders, and a paint gun, and even though I don't even use it but maybe once every 2 weeks shingle your house once without one and then do it with one and you will realize how much easier it makes life. At work (a dealership) I could not even imagine the amount of money I would lose doing everything by hand. Impact gums do break bolts lose that would break off heads of the bolts with hand tools due to the impacting action. Basically they make life easier and if you get GOOD ones they will eventually pay for themselves just in the cost of not having to replace broken bolts.

 

interesting, so you'd say that an impact will break less bolts than by hand... someone was telling me the reverse.

 

I would say they either don't have a good impact or are trying to remove too small of bolts with it. The only time I ever break bolts is by over tightening them on smaller sized bolts like 14mm bolts with a 8mm x 1.25 shaft and thread pitch. I use a Snappon 3/8 impact with 350ftlb of torque most of the time and a Snappon 1/2 impact with 150ftlb of torque for the big, really stubborn bolts. I work with guys that use there impacts to remove 10mm tranny pan bolts and never break any. Really rusty bolts should be sprayed with penitrating oil first to be safe but I don't ever have problems. If I replace an exhaust I spray the bolts and nuts down with lube, hook up my impact and start removing them, they don't break.

When buying an impact the tourqe rating and blows per minute are very important to the selection. More blows per minute saves time because when the impact hits quickly the bolt does not heat up as quickly weakening the metal. When bolts break from impacts they were crossthreaded to begin with or the head gets twisted off from the weakened metal from the large amounts of friction.

Plain and simple I won't work on cars anymore without my air tools (I know I'm a baby).

 

Ive broken more bolts with my impact. In fact ive never brokena bolt by hand. Seen impact break off the upper link cross bolt a ton of times. Thats not fun to get out. MOst of the time it results in a new spindle. I always loosen them by hand and they never break. Theres no feedback from an impact so its really easy to break off rusted bolts and overtighten and break off bolts when putting them back in.

 

Thats what i'm afraid of. Now that i'm figuring out how to turn a wrench and roughly feel ft-lbs, the wrench seems less important. I'd like to try it out anyway.

 

Speed is one of the benefits of air tools. Impact wrenches apply pulses of force rather than a steady force, making them useful when trying to break loose a seized or rusted fastener (applying a steady force of the same amount with a hand tool can cause the bolt to stretch and/or break). The down side is that using air tools can be like using a sledge hammer to drive nails...often times a more precise and discriminating tool is the better choice.

I like to use an air wrench for removing fasteners, and I bring out the impact wrench only when the situation calls for it. When tightening fasteners, I sometimes use an air wrench to tighten them most of the way then finish it off with a torque wrench.

Also, an impact wrench can be useful for dealing with fasteners like a crank pulley bolt or the nuts on the top of the VW strut assemblies - where its tought to get a hold of the bolt that the nut is going onto/coming off. With hand tools you find the bolt just spins, but with an impact wrench the hammering action will cause the nut to spin off without the bolt turning very much.

If you want to use an air and impact wrench, be sure to get a large enough tank with a sufficient reserve (45+ gal should be enough) or you'll find yourself waiting for the pump to fill the tank up. The "contractor" style compressors with small tanks can really be frustrating to use for anything but powering a nail gun.

The pump hp rating is less important IMHO. 5+ hp should work great. I do think you'll find that the higher the hp, the noisier the pump, but a higher hp pump may run less because it moves the same amount of air in less time (the noise factor may not even be an issue for most people, but if you have neighbors apt to complain about such things, it's worth noting).

If you need an orbital sander or a die grinder, air tools kick butt over their electric powered counterparts. And when it comes time to fill the tires for an autocross/track day, or fill your tire tank, filling station air hoses are hit and miss if you are needing anything over 45 psi...with your own compressor you always have the air you need on hand.