When is an impact needed? Task isn’t possible with a ratchet?

[Doonsberry]

I used to think impacts were only time saving tools. That you could do everything with a ratchet by hand, albeit slower. I did some car work at a buddy’s house this weekend and I came across a couple situations where I literally wouldn’t have been able to do the job by hand.

They were awkward angles where I needed to line up the fastener and get it started in the thread while using my other hand to push hoses and stuff aside for clearance. I tried to do it by hand but was not able to catch the threads with the fastener given the 10 degrees of movement I had. But with the impact, since it could get 360 degrees of movement on the fastener, I was able to catch the threads.

Makes me wonder what jobs/tasks are just otherwise impossible without an impact. I’m not talking about flat rate pro work or time saving. I mean, just literally can’t do it without an impact.

What jobs are those and how often do you come across them? Where impact is more than mere convenience but it’s a true necessity?

I think one of the best examples is rusty car exhaust. Because exhaust are on rubber hangers and can flop around the only leverage you can get is between your wrench hand and rachet hand. If you start pushing **** around too much on a rusty tired exhaust you can break other **** like the manifold flange...which can lead to breaking even more un-fun ****. Put a wrench and a impact on it and you don't have to ask nicely. It's not about the torque, it's the perfect leverage right at the bolt and the hammering/vibration that breaks the bolt loose. I use them on pretty much anything rusty and bigger than 9/16- 15mm. I do not however use them on motorcycles where beat up fasteners look like ***.

 

[Pinemarten]

If I can't start a fastener with my fingers, I'll grab an electric screwdriver or air ratchet that I can run at super slow speed to avoid cross threading. Once it is started correctly, I can use whatever works best for the task.

 

[strutaeng]

Another one I just thought about was those concrete screw anchors. I don't know of anyone that installs those with a ratchet, certainly not in any jobsites I've been to. The threads of the anchor cut into the pilot hole, so I imagine using a ratchet would be painful.

We are not limited to mechanic work, are we?

 

[Ingram306]

Reinstalling drain plugs it’s a must after an oil change to ensure no leaks.

 

[AEAdam]

I own at least 10-15 impacts (my bad, I just recounted 21), if I count both air and cordless, and I use them at every opportunity. BUT THE QUESTION WAS: "Is there anything an impact will do that a ratchet cannot?" The answer to that question is NOT MUCH. They build the Pyramids without power tools. Now I'm sure that was a pain in the *** but it was obviously possible. It's probably because I'm German that I'm literal. If you ask me a question I attempt to provide a specific answer to THAT question. If the question was "Are impacts great?" I would have answered in the affirmative but that wasn't the question.

Maybe a related question we should ask is, what besides a basic set of sockets and combination wrenches is really required to do work productively on cars and light trucks.

Impact gun would be at that top of that list, but I have a bunch of specialty tools that get me out of jams. Slight criticism, I see mechanics toolbox tours on you tube and they have a drawer full of sockets in all the basic configurations 6pt 12pt, deep and shallow, chrome and impact, SAE and metric. And they seem to congratulate themselves on having a “complete” set of sockets.

For me the “other stuff” includes:
Semi deep sockets (use all the time but not really special).
Swivel sockets
Stubby, long, swivel/ball bit sockets
I have low profile socket set I never use
Zero offset DBE wrenches that get me out of jambs.
Long flex ratchets including my beloved SHLF80A
Xxl non flex 1/4” and 3/8” ratchets
Ratcheting screwdrivers with 1/4” square drive shanks
Then every kind of extension.

I don’t have any flex head wrenches. But these other “basics” are what I rely on to accomplish anything tricky. I dip into this stuff on almost every job.

BTW, you might find this interesting. I was working in Cape Canaveral. Those guys had blue point carts and very basic tools. I think all purchased by NASA for the shuttle. I thought they were poorly equipped. My home box was way better outfitted. I never followed up to see if I was able to get the guys better stuff (like swivels, ratcheting wrenches, better wobbles). People all think Space is the pinnacle of everything. Gives me no pleasure to say it’s just not.

 

[oldschoolcraft]

Zero offset DBE wrenches that get me out of jambs.

I dont own any zero offset box end wrenches. I’ve been eyeing up Protos zero offset combination ratcheting wrenches, non-reversible.

Do you think that could serve the same purpose or do you think the zero offset box end needs to be fixed and non-ratcheting?

 

[driftpin]

I've never found an instance where an impact was necessary to install or tighten anything. I've had situations where the impact would break something loose when wrenches/breaker bars failed. I've also used a breaker bar to loosen fasteners that my impacts wouldn't.

On some motorcycles unless you have a special holder tool, an impact is the only way to disassemble and reassemble front forks. Replacing a chuck on a drill is another place the impact is the only way. Of course the instructions say to insert an Allen key and hit it with a hammer to remove the chuck. Good luck to that!

I second the use of an air tool to loosen the allen screw (or bolt if you prefer) in a traditional motorcycle front end, at the slider. It makes a vexing project a quick p-ffft! and it's loose, catch that stinky oil! Who's old-enough to recall when the Japanese used fish oil in their forks?

It’s called a strap wrench.

I've just called it a chainwhip. (Mention of removing a freehub on a bicycle.)

In my toolbox, a strap wrench is what you use on a chrome-plated plumbing fixture or to provide tension on something you don't want to mar its finish.

Up here in rust land the hammering force of an impact helps loosening things whereas reefing on it with a big ratchet or breaker bar can twist and snap it.

Impacts are also the best tool to use for applications such as removing harmonic balancer bolts or other nuts and bolts on something that would otherwise turn with a normal ratchet.

I agree with both.

 

[Firebrick43]

I dont own any zero offset box end wrenches. I’ve been eyeing up Protos zero offset combination ratcheting wrenches, non-reversible.

Do you think that could serve the same purpose or do you think the zero offset box end needs to be fixed and non-ratcheting?

They get you into jambs when you run a fastener to a wall and cant get the wrench off. Also they are terrible at tearing up your hand because the lack of offset puts them inline with other nearby fasteners and such

 

[Firebrick43]

I second the use of an air tool to loosen the allen screw (or bolt if you prefer) in a traditional motorcycle front end, at the slider. It makes a vexing project a quick p-ffft! and it's loose, catch that stinky oil! Who's old-enough to recall when the Japanese used fish oil in their forks?

I've just called it a chainwhip. (Mention of removing a freehub on a bicycle.)

In my toolbox, a strap wrench is what you use on a chrome-plated plumbing fixture or to provide tension on something you don't want to mar its finish.

I agree with both.

They make large strap wrenches. we used them all the time on spindles for CNC machine to hold them without marring the surface. This one will handle a 16" diameter object.

https://www.otctools.com/products/multi-purpose-strap-wrench

 

[tamaraw]

While an impact could be used to save time in certain scenarios, it is a significantly different tool than a ratchet and not interchangeable.

- Hammering action makes it much less likely to strip or twist fastener heads vs constant tension from a lever.

- Much safer for the operator when a seized fastener gives way suddenly.

- The only option when you can't get a good grip on a smaller sub-assembly and using a lever by hand would just make the whole thing turn.

Doonsberry posted a good example of that last one with the exhaust hanger scenario. I actually used my impact this morning to disassemble some brake calipers that had already been removed from the vehicle. Good luck using a ratchet on that without a big old bench vise set up.

 

[tamaraw]

I dont own any zero offset box end wrenches. I’ve been eyeing up Protos zero offset combination ratcheting wrenches, non-reversible.

Do you think that could serve the same purpose or do you think the zero offset box end needs to be fixed and non-ratcheting?

Well, a fixed box end lets you smack it with your hand or a deadblow.

Can't really do that with a ratcheting model but obviously that has its own advantages.

 

[murd]

#1 thing to NOT ever do with an impact would be starting fasteners as you described. That's a real good way to crossthread the bolts/strip threads.

Yep, I had my winter tires done in a rush by a different garage once. In the spring I had to break off 3 studs and replace them. All cross threaded.

 

[AEAdam]

I dont own any zero offset box end wrenches. I’ve been eyeing up Protos zero offset combination ratcheting wrenches, non-reversible.

Do you think that could serve the same purpose or do you think the zero offset box end needs to be fixed and non-ratcheting?

I have the snap on version of these.

quite handy. I could take or leave the ratchet end.

 

[RedneckWelder]

When you can’t get enough leverage from a ratchet for clearance, can’t hit, etc but you can snake a universal joint and an extension in for an impact.

Plenty of times I’ve encountered clearance issues that don’t allow for advancing the ratchet to the next tooth either.

 

[no704]

Pulley swap on an alternator.

 

[VolvoRyan]

As mentioned above several times, the nature of "impact" is very different than a long hard pull. It's not just about oomph.

For example, you may have a stuck fastener: A 50 ft-lb constant tug may just break it, where an impact may get it out. Vibrations are a magical force.

-Ryan

 

[Firebrick43]

Some mentioned alternators and such, they can break magnets in them. I removed a harley crankshaft primary sprocket with an impact, which is also the alternator on the bike. The impact shattered one of the magnet while doing so.

 

[dnschmidt]

Some mentioned alternators and such, they can break magnets in them. I removed a harley crankshaft primary sprocket with an impact, which is also the alternator on the bike. The impact shattered one of the magnet while doing so.

What on a Harley doesn't break? You can hate the Jap bikes all you want but they're just built better and last a lot longer.

 

[rockettauto]

Idk about any absolutely can't dos but often times there isn't a great way of locking a rotating shaft with a nut could be done but might take waaaaaay longer without the impact.

The other is stuck rusty stuff. There are many times not using an impact would mean you'll be breaking it rather than having it actually come loose.

 

[rockettauto]

Some mentioned alternators and such, they can break magnets in them. I removed a harley crankshaft primary sprocket with an impact, which is also the alternator on the bike. The impact shattered one of the magnet while doing so.

To be fair, the manual specifically warns you not to use an impact on that.

 

[Firebrick43]

What on a Harley doesn't break? You can hate the Jap bikes all you want but they're just built better and last a lot longer.

Its actually been the cheapest and easiest bike to maintain that I have ever owned. I would of agreed with you years ago from all the UJM's that I have owned before this bike but a sportster is a pretty good standard bike. I have 40,000 miles on it and have not done anything other than one set of tires, a battery, a pair of spark plugs and oil filters.

The primary sprocket magnets were not broke from use, I was changing it and the primary chain out to lower the gear ratio.

 

[Firebrick43]

To be fair, the manual specifically warns you not to use an impact on that.

That is why I am pointing it out, passing along some wisdom learned from hard knocks, I am sure it does on most alternators and stators. I was pointing it out so someone didn't take post 55 seriously.

 

[rockettauto]

That is why I am pointing it out, passing along some wisdom learned from hard knocks, I am sure it does on most alternators and stators. I was pointing it out so someone didn't take post 55 seriously.

Oh idk, I just meant on that particular spot on Harleys. I've risked it several times myself though, but I've been lucky.

 

[ching0n]

Using several impacts on low often beats the breaker bar which will sometimes snap sh!t up.

 

[RichWolfson]

Damn I need to replace my friend’s water heater later this year. I have an m12 fuel 1/2” drive. Is that enough for this job or do I need m18?

Try. Some are easier than others. And some require a Thunder Gun!

 

[RichWolfson]

An 8 foot cheater bar and your entire body is like 900-1600 ft-lbs depending how big you are.

Yes. But the water heater moves. Hence the necessity of the impact gun. ///Rich

 

[Meursault74]

It’s called a strap wrench.

for bike sprockets they have a specific one called a chain whip
I have 2 of them. One I bought and one I made from a used chain and a piece of metal I had lying around.

I've also seen pliers that have pieces of chain attached to grab the gears as well.

 

[jonesg]

#1 thing to NOT ever do with an impact would be starting fasteners as you described. That's a real good way to crossthread the bolts/strip threads.

definitely, never try to catch threads with a powered tool, especially into the engine block. (water pump etc).

 

[f121]

I dont own any zero offset box end wrenches. I’ve been eyeing up Protos zero offset combination ratcheting wrenches, non-reversible.

Do you think that could serve the same purpose or do you think the zero offset box end needs to be fixed and non-ratcheting?

I’ve got a cheap set of non ratcheting and the snap on ones with ratcheting at one end and fixed at the other. The non ratcheting ones never get used now I have the ones that do both.

I use them most for suspension jobs, where something is tight but I can’t get an impact in, and fasteners on rusty vehicles where I don’t care if a bolt snaps or comes undone, I just want it off as quick as possible. If it comes undone the ratchet end is invaluable for dragging stuff with a rusty thread through a nut.

 

[Citation]

I find them handy when you can't reasonably apply counter torque. For example, breaking a nut off a ball joint. With just a bit of lateral pressure on the ball joint it won't spin while the impact takes the nut off. The nut on the top of a shock shaft is another example. When pulling the old shocks I can just grab the sock shaft with a set of pliers then zip the top nut off with the impact.

 

[bwringer]

I work on lawnmowers quite often, I use an impact for the flywheel nut and cutting blade(s).

Overall, I don't think risk mitigation is optional.

In this case, and many others, the impact is actually much safer than trying to lock the blade or shaft and applying hand force. In that case, you're avoiding the danger of a moving blade.

Similarly, you can use an impact to avoid many kinds of danger from the machine moving while you're applying monster torque with a breaker bar. For example, sure, I've broken free many CV axle nuts by hand, but even with good precautions the car can move, and now that I have access to impact tools, this is a risk I avoid.

Same for stuff like work on suspensions while the car is on a lift or jack stands; applying a lot of force with a breaker bar can move the car, so it's a risk best avoided.

Another type of injury you should use an impact to avoid if possible is the sudden release; the bloodshed and carnage that can result when a fastener breaks free. Busted knuckles aren't funny, and injuries can be far worse.

Several have mentioned this above, but I'd also argue impacts and power tools are indispensable, and even required, for avoiding RSI (repetitive stress injuries).

For example, my damaged wrists have a pretty low limit for how much twisting of an old-fashioned screwdriver they'll tolerate. I will go to quite a lot of trouble to use power tools to save wear and tear on my hands and wrists.

On some motorcycles unless you have a special holder tool, an impact is the only way to disassemble and reassemble front forks.

Agreed. That said, it's best to have or make a holder tool for reassembly, and I have several sizes and configurations. (Although, in a pinch, and with a deft and delicate touch, sure, you can use the impact for reassembly.)

The problem is that for many motorcycles, the information is treated as a state secret for some reason. It's often hard or impossible to figure out what sort of holder you need until the damn thing is apart and the damper rod is in your hand. The manuals never contain the actual info you need -- "hey, a 19mm or 3/4" nut fits the top of the damper rod." would be mighty useful, but it's never mentioned. And even the "helpful" posts of forums or even videos often skip the actual damn number you need.

Who's old-enough to recall when the Japanese used fish oil in their forks?

I work on old Japanese bikes fairly often and have encountered this stuff several times. I don't know whether it's actually fish oil or what, but damn it sure smells like low tide... amazing how many people never once think to change the fork oil in 40 years.

 

[a390st]

I absolutely appreciate impact as a time saver, and for times where something would try to spin without unthreading. Let's remember that slugging wrenches have been around for a while and don't require power or air. They certainly aren't as easy to use and require clearance to swing a hammer, but they do break fastenets free (or just break them).

 

[firebirdparts]

I am an "impact skeptic" like OP. It should be obvious that the impact doesn't require a counterhold, and so is convenient when no counter hold is possible. There are lots of situations like that.

Much as I hate to admit it, there are lots of applications where you simply cannot get the required torque using anything manual. I don't see those at home, ever. I do see them at work.

I am unsure, personally, about the effects of hammering being good or bad for your chances of success on a stuck fastener. I think sometimes it can be bad, but it's hard to be sure.

I would never start any fastener with one. Never have and never will.

 

[American Locomotive]

As many mentioned, it's not a good idea to use an impact to start bolts - especially at an angle. It's a good way to cross-thread and destroy things unless you are very careful.

I don't think there are any tasks that are necessarily "impossible" to do without an impact, but there are many tasks that are extremely difficult to do without them. Basically any task that you cannot reliably prevent the workpiece from moving, an impact makes a whole lot easier. Examples include crankshaft bolts, water heater anodes, ball-joint/tie-rod nuts, lug-nuts (with car in the air), and so on.

Why would you ever use a ratchet on a high torque application? You’re just asking for trouble. If they were ment to then why are there breaker bars? Hence the name BREAKER. You must like destroying expensive tools from abuse

I have never broken a ratchet from high-torque. Modern ratchets (even the Taiwanese ones) are so strong that you will shear the anvil off before the ratchet mechanism itself fails. I have had multiple breaker bars fail catastrophically on me (including brand-name ones), while I've never had a ratchet just straight up break while being abused. I've broken a breaker bar trying to remove a bolt, that a ratchet + a cheater pipe removed successfully immediately after. Breaker bars are a waste of time for most applications, IMO.

 

[BombShelter]

I use a breaker bar as a last resort, maybe I've just had bad luck but I've broken too many studs and bolts over the years. I don't use air impact, the cordless work great most of the time and I have a corded DeWalt that works on big truck tires. I've got different cordless drivers so I can move up in torque if needed.

While most of college was a haze I do remember talking about interstitial molecules and the bonding action of the nut and bolt at the atomic level. The professor claimed banging on the nut a few times would help loosen this bond and I've felt the the banging action of impact drivers did this easier than a hammer.

I work on my vintage tools/audio/cars all the time, the time savings alone is worth it but your arms and wrist also take a beating from doing it manually. I never worry about stripping threads, breaking nuts or rounding edges anymore. Plus there's the few times (like mowers) where you don't need to figure out how to hold a rotating part. I just had one a few weeks ago, maybe a pump impellor?

 

[Jtels85]

Yamaha Drive 2 golf carts. We install rear seat kits and getting the bolt to bite when mounting the rear roof bars back to the new aftermarket seat-back bars is a ***** by hand/ratchet. We found that using a c-clamp to squeeze the bars together since they don't align properly, and the speed of an impact usually gets them to bite on the first try. Doing this by hand just doesn't work, ever.

 

[Oh_Snap]

I used to think impacts were only time saving tools. That you could do everything with a ratchet by hand, albeit slower. I did some car work at a buddy’s house this weekend and I came across a couple situations where I literally wouldn’t have been able to do the job by hand.

They were awkward angles where I needed to line up the fastener and get it started in the thread while using my other hand to push hoses and stuff aside for clearance. I tried to do it by hand but was not able to catch the threads with the fastener given the 10 degrees of movement I had. But with the impact, since it could get 360 degrees of movement on the fastener, I was able to catch the threads.

Makes me wonder what jobs/tasks are just otherwise impossible without an impact. I’m not talking about flat rate pro work or time saving. I mean, just literally can’t do it without an impact.

What jobs are those and how often do you come across them? Where impact is more than mere convenience but it’s a true necessity?

I just disassembled my 5th Snap-on YA700 jack for rebuild.

There are two 28mm nuts on the rear caster wheels that spin regardless of the size of the ratchet. That's a job for a 3/8" impact gun.

There is a 46mm nut on the front of the hydraulic cylinder. That's a job for a 1/2" impact gun.