Impact Wrench or Impact Driver

Django x2 · 2 Jun 2014 at 09:39

Never the twain shall meet, but which should I buy (or both).

Got a mini car project on the horizon (not the model), and fancy a new man toy. Cordless Impact Wrench, aka, the whippy gun, would be used traditionally to remove wheel nuts / bolts and applies rotational force only.

Impact driver applies both rotational force and downwards force, so, assuming I had a very annoying disc retaining screw, or suspension hub mount that wouldn't come out, an impact driver would be a better choice than an impact wrench? Correct?

Do I need both, or, should I buy both

daelo · 2 Jun 2014 at 09:58

Correct me if i'm wrong , but isnt the idea of the "whippy gun" to apply a sudden and high rotational force to crack open stubborn bolts?

Whereas an impact driver is more suited to winding in screws in metal/aluminium etc where the downwards force helps to 'drive' the screw in.

Also with an impact driver on bolts, they might round fairly easily if battered with a constant rotational force and also downwards force, I certainly know this is true for winding in screws that wont go in, you end up screwing the head in no time!

Sasso · 2 Jun 2014 at 10:02

daelo said:
Correct me if i'm wrong , but isnt the idea of the "whippy gun" to apply a sudden and high rotational force to crack open stubborn bolts?

Whereas an impact driver is more suited to winding in screws in metal/aluminium etc where the downwards force helps to 'drive' the screw in.

Also with an impact driver on bolts, they might round fairly easily if battered with a constant rotational force and also downwards force, I certainly know this is true for winding in screws that wont go in, you end up screwing the head in no time!

this this guy knows. thought impact drivers were more for drilling in masonry work, when ya need to put a hole through several layers of concrete or what ever so you have the drilling action and the "hammering" downward force too... not for turning bolts etc... I could be wrong....

lemonade · 2 Jun 2014 at 10:14

I used an impact driver to take of screws that was bedded in holding the discs, worked a treat!

tigerstyle · 2 Jun 2014 at 10:29

Sasso said:
this this guy knows. thought impact drivers were more for drilling in masonry work, when ya need to put a hole through several layers of concrete or what ever so you have the drilling action and the "hammering" downward force too... not for turning bolts etc... I could be wrong....

No, impact does not mean hammer.

A hammer means hammer, impact means rotational force.
So a Hammer drill/Percussion drill/SDS has a hammer action for concrete, useless on wood and metal.

An impact driver/wrench, just different terminology that gets thrown around, is a pure turning force. For nuts and bolts.

Sealey do a fairly decent (18V?) cordless one, it's a pretty big beast though.
There are traditional Makita/DeWalt alternatives that would be more useful on other projects around the house perhaps.

Sasso · 2 Jun 2014 at 10:35

ah rightyo

things are clearer now

Dr Who · 2 Jun 2014 at 11:12

Impact Driver for Screws and Whippy Gun for bolts/Nuts Simples.

Impact Drivers are good for Motorcycle casings with soft screws as an example.

Django x2 · 2 Jun 2014 at 12:29

Cool. It's just that there is a considerable price difference between the two.

Impact wrench will apply just rotational force through high torque whilst an impact driver will also "hammer" down on said screw / bolt to shock it whilst also applying high rotational torque. I used to, for instance, hammer a socket allen onto the disc bolt to shock it loose before using a normal wrench or breaker bar to loosen.

Clarkey · 2 Jun 2014 at 12:34

I'd save so much time with a rattle gun but am too tight to buy one. One day I will, same day I get around to buying a man spec jack instead of crappy little hobby ones.

Django x2 · 2 Jun 2014 at 12:40

I'm in the position now to think, "you know what, it's worth it" as I'm forever tinkering with something somewhere

If I buy a 1/4" one, I assume I can move up to 1/2" (or down) with relevant adapters and the like?

tigerstyle · 2 Jun 2014 at 12:46

Django, be careful dude, your theory is wrong on the impact/hammer thing.
Also a 1/4'' sized one is made/geared/tested for 1/4'' stuff, as soon as you load up a 1/2'' adapter on it you're straining it a lot more, it'll work for a bit, and then it'll break!

Clarkey · 2 Jun 2014 at 12:59

1/4" is good for nothing tbh get a 1/2". You want to use proper impact sockets anyway and they are almost always 1/2" drive for stuff on a passenger car anyway.

Django x2 · 2 Jun 2014 at 13:55

tigerstyle said:
Django, be careful dude, your theory is wrong on the impact/hammer thing.
Also a 1/4'' sized one is made/geared/tested for 1/4'' stuff, as soon as you load up a 1/2'' adapter on it you're straining it a lot more, it'll work for a bit, and then it'll break!

How do you mean? The impact wrench applies downward force as well as rotational force. Perhaps not in a "hammer" style, but the force is still there initially.

Clarkey, thanks, will keep an eye out for 1/2

pepsilol · 2 Jun 2014 at 14:19

Clarkey said:
1/4" is good for nothing tbh get a 1/2". You want to use proper impact sockets anyway and they are almost always 1/2" drive for stuff on a passenger car anyway.

Battery powered 1/4" impact gun is the best thing ever! It's the ultimate lazy tool.

But yes for serious stuff 1/2 impact.

Clarkey · 2 Jun 2014 at 14:22

Not convinced, I think the majority of 1/4" tools I've used have ended up broken. 3/8 and 1/2 never break.

pepsilol · 2 Jun 2014 at 14:26

Clarkey said:
Not convinced, I think the majority of 1/4" tools I've used have ended up broken. 3/8 and 1/2 never break.

If you're breaking 1/4 tools you either have cheap tools or using them for the wrong purpose.

For instance, you wouldn't break 1/4 tools taking a timing cover off, or undoing battery terminals, covers etc etc.

Clarkey · 2 Jun 2014 at 15:02

I'd just use a 3/8 one and not bother with 1/4.

Being fair though, this is mostly based on Halfords tool sets. The only 6 point sockets they provide are 1/4" so when you round a tricky nut with the 12 point try it with the 6 point one and it immediately breaks, then you go and buy a 6 point 3/8" one.

tigerstyle · 2 Jun 2014 at 15:14

Django x2 said:
How do you mean? The impact wrench applies downward force as well as rotational force. Perhaps not in a "hammer" style, but the force is still there initially.

The only downward force comes from your hand pressing on it, same as a screwdriver, ratchet, spanner etc.
For the majority of the work, it's the side to side action that really helps

This goes into it, pretty well.

You can see the flywheel is mostly applying it's force to turn the bolt not hammer it.

Clarkey · 2 Jun 2014 at 15:20

What about the force from hitting it directly into the fastener with a hammer then :confused:

They are useful for screws where it's hard to turn it with force without the bit slipping out.

Django x2 · 2 Jun 2014 at 15:36

This is what I'm referring to:

Powered impact drivers use a motor or compressed air to rapidly and repeatedly deliver rotational and impact forces, providing considerable speed and productivity advantages. They are often used in construction and manufacturing to replace screwdrivers where speed and operator fatigue are significant issues. In some situations however, this type falls short since current designs cannot deliver as much downward blow as a manual unit. This can be especially true on very stubbornly stuck fasteners, or screws (particularly Phillips) with damaged/"stripped" head slots.

A cordless impact driver, will "drive" down on the screw / bolt in question in addition to any force applied by me, as well as rotate.