[Drew]

A manual impact driver requires you to hit something hard with a hammer, if that something is in a weak structure you might find that you've just removed said screw/bolt/whatever by driving it straight through the body of whatever the bolt/screw/nut/whatever is in. Electric is basically the same mechanism as a hammer drill, a couple of spring preloaded ball bearings stop the bit from spinning and that impact is the impact you're using to undo the screwboltthing.

 

[Drew]

Screws or bolts? The one I posted up a while ago goes upto about 100Nm but I'm a bit skeptical about whether its really capable of smashing that out, but if it did 10% of 100Nm it would still be pumping out a few multiples of the maximum you'd ever achieve with a screwdriver.

 

[Drew]

no i was talking about screws
there's a fair number of them very tight in places
like the ones on the carby
seemed like they were superglued to the carbs

i know the difference between a screw and a bolt

im not looking for an impact driver for bolts, i dont think you can even use an impact driver on bolts, unless you cut a groove in it
what i need i something to undo tight screws which won't chew them up
the last owner really fucked up some screws on my bike

Rattle gun is a coloquialism for a powered impact driver

You just have to get the correct impact bits to deal with almost anything with them.

FYI I've used my little electric impact driver on badly stripped carby screws among other things, all you've got to do is apply a bit of pressure to help the tool bite, then it will rip em right out.

 

[Drew]

This is the one that I've got, I've entertained the idea of buying a bigger one to go with it, but this certainly does the job for most things.

http://www.bosch-pt.com.au/papocs-au/Trade+and+Industry/Tools/AU/en/gw/Compact+Duty+10.8+V+Lithium-ion/129924/GDR+10%2C8+V-LI/11765/index.htm

 

[Drew]

Theres a mob in the UK selling one for $230 with batteries and charger... I'm pretty sure that I bought mine from some people in sydney with an angle drive drill and a torch for about $300 though.