An impact driver does exactly that. Applies a sudden impact as well as a turning force.

A rattle gun is sometimes called an impact wrench. Hence the confusion.

What I'm presuming you're after is a cordless rattle gun/impact wrench.
http://www.ryobi.com.au/Products/ONEPlus/Drills/BIW180G

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Used one of these the other day. Was very good.

New Repco Premium Quality Impact Gun

Had a look at home. That is the bigger of the two. It happily undid the driveshaft bolts on my car.

+1 for what Andy said. The impact drivers you guys have been putting up are more aimed at tek screws and the like rather than undoing wheel nuts.

This is an impact driver - 165 nm max torque

BTD145RFE-18V Mobile 3 Speed Brushless Impact Driver

This is the smaller of the two makita rattle guns. 230nm. As I say it is a good small unit but will struggle to crack wheel nuts if you torqued them up. This is what we carry in the rally car.

BTW251RFE-18V LXT Mobile Impact Wrench

This is the big dog from Makita. Bloody heavy but an awesome unit - 440nm

BTW450RFE-18V LXT Mobile Impact Wrench

Brendon

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hitachi = smallest with the most power for size.

Listen to Andy - working on rally cars his rattle gun has undone more bolts in a couple of years than you will undo in your life.

I have Hitachi and run them in the rally cras as well.

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12.463 1/4 mile, not bad for an old school Liberty [DECEASED]

MY08 Liberty Tuned by STi

where can you buy the Hitachi guns?

EDIT: which one of these lah
http://www.hitachi-powertools.com.au...=226&CatID=178
http://www.hitachi-powertools.com.au...=254&CatID=161
http://www.hitachi-powertools.com.au...D=84&CatID=161

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I have one of these panasonic impact wrenches. Easily undoes wheel nuts, drive shaft nuts, crank bolts etc. easily makes it's rated torque and gets me about a week of undoing and doing them back up again at work. great range of tools!

EY7547LR2S57

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Can you adjust the torque on most of these units, say you want your wheel lugs at 90nm of torque?

+1

Old man has one and after using it I decided to get one too. Awesome unit and is more than enough for all your car needs.

Make sure it is is held in there securely, I've seen 1 come loose during a rollover.

The Ryobi one+ doesn't have torque adjustment, but use a torque wrench when doing up the nuts anyway.

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+1 for Andy's comments.

Personally I use a Makita 18V BTW251 Cordless Impact Wrench (Rattle Gun) Has the Li-on batteries, is light weight and will rattle off wheel nuts no drama and drive shaft nuts without much trouble. Battery life is good and I have no dramas getting through a whole day of servicing up to 4 rally cars. That equates at up to 24 wheels (on one side of each car) going on and off the cars + sump guard bolts etc during an event. The Makita battery charger will fully charge a battery in 22 minutes anyway.
Most of our service crew have the equally capable Hitachi 18V cordless impact wrenches. The Hitachi's work pretty well and seem to have a similar battery life. Most of our crew are tradies in the building game and bought the Hitachi 18V multi tool packages. Surprising how much power the 18V cordless angle grinder has.

Pricing:The Makita BTW251 (tool only) is around $240 from All Tools in Bayswater, not sure on the whole kit price with charger, batteries and case. Tool Mart may be worth a call.
Good deals on Ebay too, however a word of caution on buying off Ebay. The cordless tool packages are usually brand new as advertised, however the chargers are often US or US modified from 110V to 240V. Better off to buy a 18V drill kit or battery & charger locally and then buy the tool only off Ebay, cheapest I have seen for the Makita BTW251 is $184.00.

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