Rattle guns aka Impact wrenches

[Jules]

I'm finding as I get older that strength is seeping away quietly and I notice it in various ways - the latest was changing the blade disc and blades on my Honda self propelled mower, whereby I needed to loosen the old rusted bolts, then tighten the new shiney ones to torque. I noted on Utube most people used a rattle gun, which I dont have but am now thinking of getting!
Knowing nothing about such things I googled Makita 18v tools (I have a few already) and noted that they have many types and sizes and for the life of me cannot understand where a torque of 1200 Nm (the highest capacity) would be needed by the average person like me/us. I figured that the smaller and cheaper one rated at (only!) 330 Nm would be more than enough for the average shed worker for cars/bikes/mowers etc BUT I thought I'd ask you learned people who probably use them most of the time now (?), what your thoughts are regarding capacity/size/features etc etc - thoughts??

[Roger (Doomtrainbarx)]

I have a DeWalt 1/2" drive 18v with variable torque settings - seems to do everything I need.

[Bsareg]

I've a Makita 3/8" gun which I find does most things on a bike. I find it's loosening things that are the main problem and the 3/8" gun copes well. I prefer to tighten thing by hand for 'feel', even crank pin nuts (with a long bar)

[Jules]

Hi Roger, what is max capacity you have used with it (vs its rating) and have you ever cross checked the torque with a wrench?
Hi Bsareg, do you know what the rated capacity of the Makita is and have you ever exceeded it ie it failed to do the job? I just googled Makita here and there is only 1/2,7/16 (?) and 3/4 sizes here it seems.... cheers

[KiwiGF]

1/2” drive Dewalt with 600 ft lb here, on lower setting it only gives about 80 ft lb max.

If you use a an extension you lose a lot of ft lb so I recommend something with that sort of power. Big sockets also reduce ft lb.

Biggest benefit has to be doing car wheel nuts…..but a 600 ft lb rated wrench can easily break a 3/8” stud, and maybe a 1/2” one.

They are not the answer to stuck/rusted nuts….they either don’t move or maybe snap off, I find a 500mm breaker bar gives more torque than the wrench.

[Bsareg]

Been out to the workshop to check, had three years use out of it  and not looked at it closely. It's model DTD146 18v. I never realised its actually a 1/4" hex drive with an 3/8" adapter. There's no indication of its torque (not even in the manual) so Makita are probable not proud of the figure. As said though, it's done most of what I've asked of it.

[Greybeard]

I would not trust a rattle gun to give an accurate torque setting, to my mind it would be like yanking a torque wrench rather than giving it a steady pressure. I use my, air powered, RG to tighten the engine shock absorber nut on the A10 because it avoids having to lock the crankshaft. I have used my RG on the car wheel nuts.

[Jules]

any idea of the torque you have driven the engine shock absorber up to GB?

[Greybeard]

any idea of the torque you have driven the engine shock absorber up to GB?

Effing tight!

[a10 gf]

Just a comment, some time ago needed to use the (18v) impact driver, but no go. Motor refused to increase rpm, and no force whatsoever at the tool output.  With whatever (fully charged) battery.

Ready for throw away, but never doing that before at least 1 inspection. And yes, the grease in the star gear was close to completely solidified (age & humidity, was under freezing temp at the time, impact driver left in the car). The motor had zero chance overcoming that braking effect inside the gearbox.

Dismantled, cleaned and fresh\quality grease = good as new.

Example of star gearbox, used whenever big force\reduction in a confined place is needed. Ref. helicopters.
Got that in many handtools. Also in starter motor of my diesel cars, which have needed clean\regrease as well, old grease combined with carbon powder from brush wear = quite a thick mess.

[muskrat]

G'day Jules.
I use Snap-on 18v rattle guns and drivers all day at work. 3/8" does most of the work but the 1/2" is used on mower base plates and blades.
I've never checked the torque of them, it's a matter of feel and sound of the tool. For bolts like blade and clutch on ride on mowers I use the air gun, good for 200Lb.
At home I have 18v Ryobi 1/2" that does most jobs but I still like to use the tension wrench for final assembly.
Cheers

[sean]

I have air impacts from 3/8 to 3/4  in  I only undo bolts with them and spin the bolts up hand tight .....then use a torque wrench
the impacts undo most bolts with no problem but have a 10 to 1 torque multiplier if I find a stubborn one but its a beast to move around .
there are lots of electric and battery operated torque wrenches and torque limiting extensions like you local car shop use .
I dont use the impacts on the BSA mostly for automotive and industrial things .

[Jules]

thanks all, it seems like it will be a worthwhile add to the toolkit - there are 2 versions I'm considering max. 700Nm and min. 150Nm, vs the lower version at max. 300 Nm and min. 100Nm. While I'm tempted to go 700/150, in reality the 300/100 is lighter and smaller which makes it more attractive. 300Nm would seem more than adequate for occasional heavy duty use but is it really?? (thats 220 Ft Lbs, I dont think I've ever tightened anything up to that level in the past with a torque wrench, is that 300Nm torque spec "real" and equivalent?) cheers...

[limeyrob]

These bikes are mostly BSC threads - 26 TPI so they are very fine in the larger sizes.  They don't need much torque compared to a "modern" ie metric thread.

[terryg]

My son has a 950 Nm de Walt, switchable in 3 stages. He needed to remove the hub from his early LR Disco 3 and first we tried a breaker bar plus 2 m of pipe, thinking that setup should do the job. We couldn’t make any impression.
Parking my scepticism we switched to the de Walt and the bolt came out just like it was finger tight. I was an instant convert!
Later I was reworking the aluminium wishbones on our VW. The steel bolts had 15 years corrosion bonding them to the ally. It took 2 blowtorches and the de Walt some time to get anywhere but all was good in the end.
I mention the latter job because it points to occasionally needing the ‘extra’ that the larger rattle guns provide. That is ‘talk softly but carry a BIG stick’.

The ability to work on rotatable assemblies without needing to lock them is a big bonus too.