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What kind of impact wrench to help change mower blades?

8K views 63 replies 28 participants last post by  Steve Urquell 
#1 ·
I’m using a torque wrench to change the blades on my Cub Cadet 2146 but it’s still quite difficult. I also have a breaker bar but I’m looking for a cheap (?) impact wrench to help. (it’s a 1-1/8” nut and requires 100 ft lbs)

Can I use my small 100 PSI compressor with a small impact wrench?

Can anybody give me any recommendations?

I’m also thinking about a Makita impact wrench but they are a bit expensive for how often I would use it.
 
#2 ·
Yes, you can use an impact wrench with your air tank/compressor. A small tank just limits it's duty cycle (the compressor has to run more often to get it to full pressure than with a bigger tank), which shouldn't be a problem just doing 2 or 3 spindle bolts.

I would suggest a 1/2" harbor freight one. Don't forget to also get and use air tool lubricant for it, it's important to use regularly for it to work right.
 
#3 ·
Harbor Freight has an electric impact wrench for $60. I've used it for years.

As far as a pneumatic impact wrench, 100 psi is not the spec you need, what you need is how much cfm or cubic feet per minute your compressor puts out. Even so, a small compressor may work for you.

 
#5 ·
I just used a 1/2" impact to loosen the nuts on my blades last week, just be careful on using a impact to put the nuts/bolts back on some impacts have alot more tightening torque then others.
I was just looking at HF pneumatic impact wrenches. Found 15 ft lbs, 45 ft lbs, and 250 ft lbs.
The electric one above 230 ft lbs.
 
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#6 ·
Go with a battery operated impact. I use a DeWalt 1/2" drive model that's an 18 volt. It was a little on the high $$ side, but look around for a sale. You should be able to find something very affordable at Harbor Freight.
Duane
By the way, I forgot to mention that the battery models give you more flexibility over the air powered models. I take mine out in the yard and also down to my camp when I have "BIG" tractor repairs to do.
 
#7 ·
There still a Lot less Money then Milwaukee I Buy Dewalt for My corded power tools and Milwaukee for My Battery Operated power tools sometime I think I should have done the Opposite:)

To the OP because You want to spend the least amount the HF electric Impact should be fine for your Needs (y)
 
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#8 ·
A block of 2x4 to jam the blade so it can't turn, a box end wrench for the nut (bolt), and a 40 ounce ball pein hammer.

Turn the blade so that it is jammed by the wood, install the wrench so that it points away from you, place a foot on the wrench to keep it secure, and whack it with the hammer one, or maybe two times.

I have the pneumatic impact. I just can't be bothered stringing out 60' of air hose and lugging an impact out from the shop when a hammer and wrench are so much lighter and do the job with so much less effort. You never notice how many tools you bring out to the job until it's time to put them all away.
 
#11 ·
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#9 ·
One thing I haven't seen mentioned yet is that it's probably not a good idea to use a torque wrench to break the bolts free. The torque required to remove them may be substantially more than what is required to install, and possibly beyond your torque wrench's capacity. This could lead to ruining the torque wrench.

Agree with the suggestions above. I take mine often enough that I'm usually able to grunt 'em off with a wrench or paired wrenches. Install should be done with a single wrench or torque wrench to the proper torque specifications, no more.
 
#15 ·
Yeah, good point, I kind of glossed past that. But don't use a torque wrench to loosen things, if at all possible. That's really not what they're for, there's no benefit to be had, only possible damage to the torque wrench. Use a ratchet handle, breaker bar, or (preferably) impact tools, IMO.
 
#10 ·
I’m also thinking about a Makita impact wrench but they are a bit expensive for how often I would use it.
Are you already invested in the Makita battery ecosystem (i.e. no need to buy a charger/more batteries)? Do you do general mechanic work on your machines aside from the aforementioned blade change?

If the answer to both of those questions is "yes," then treat yourself to that wrench. Battery powered impacts are very impressive, and after the first job you do with one, you'll realize how much time during a repair is spent (aka "wasted") turning a ratchet/wrench by hand.

You'll also find a lot more uses for one than you think. Think of every time you have to use a ratchet and have to exert some force. An electric impact will do that for you in a flash.
 
#12 ·
Unless I was a commercial shop constantly removing and installing blades for a living, I wouldn't bring an impact wrench anywhere near my deck blades. My 18mm box wrench snugs up the mounting bolts just fine. There is a cupped washer that should provide some locking pressure when tightened by hand. Been cutting with decks for 45 years, and haven't had one come loose yet.
Just my opinion here, since it works for me.
 
#17 ·
Unless I was a commercial shop constantly removing and installing blades for a living, I wouldn't bring an impact wrench anywhere near my deck blades. My 18mm box wrench snugs up the mounting bolts just fine. There is a cupped washer that should provide some locking pressure when tightened by hand. Been cutting with decks for 45 years, and haven't had one come loose yet.
Just my opinion here, since it works for me.
I wouldn't use an impact to tighten things either. But you wouldn't even use one to loosen the fasteners? They seem perfect for that, to me, since you don't even need to block the blades to keep them from turning.
 
#16 ·
Thanks a bunch for the information everybody. Also, I'm using a breaker bar and not the torque wrench to remove the bolts.

How is this CENTRAL PNEUMATIC 1/2 In. Air Impact Wrench at Harbor Freight for only $27.97? It's listed as being on clearance and has 250 ft lbs of max torque. I'm not sure what the 5/8" bolt capacity means though ... (the cub cadet uses a 1-1/8" nut)

Here's another cheap one at Amazon for $25.35. It's listed a 230 ft libs.

I know these tools are most likely junk and I typically always invest in quality things that will last a while, but for this situation I really don't see myself using it outside of helping with the mower blades.
 
#18 ·
I have a bunch of air tools from my truck mechanic days but I pick up my Ryobi 1/4" cordless impact every time I can over dragging a hose out. I'll eventually buy a 1/2" but gotta wait on a deal. Not a terrible price at $139 with a battery pack and charger right now.


Those battery impact mfgs claiming "1400ft/lbs torque" are crazy. When I used to torque Cummins 855 head bolts we'd hammer them with a 1/2" impact till they stopped moving, bump them with a 3/4" impact, then click them with a 4ft long 3/4" drive torque wrench set to 305ft/lbs. We called that "torquing in sequence" (1/2" impact to 3/4" impact :D)

Below is what it really takes to hit 1400ft/lbs. 35lb CP797 tire gun. Rattled one for thousands of lug nuts with 160psi running it in truck shops. https://www.amazon.com/dp/B000NOX2T4?tag=paramatandalin-20&linkCode=ogi&th=1&psc=1


They'll probably take off the nuts if you have enough air volume and use a 3/8" hose--1/4" curly hose won't get it. . How big is your compressor? Tank size, HP, and CFM?
 
#20 ·
I use a breaker bar with a 6 point socket and use the blade removal tool to keep the blades from moving. It takes more time and getting the blade removal tool on the center blade is a pain, but no more than I change or remove them, it's not that big of deal. However, removing the blades the first time, I would have loved to have had an impact wrench nearby. Those bolts are WAY over-tightened at the factory.
 
#25 ·
100 psi is plenty of pressure. Many air impact wrenches are rated at 90 psi. Yes, I know a lot of us run higher pressure than that. We shouldn't, we are probably voiding warranty.

A skinny air hose will reduce the pressure when the air is flowing. If cases like that, short 'burps' on the air wrench will allow for maximum pressure during the 'burp'.

Later,
Jerry C
 
#30 ·
A good cordless Milwaukee M18 1/2" impact is all you need quick fast and in a hurry. No back up wrench or anything except a new set of blades. My Milwaukee M18 has 3 torque settings I use torque settings #3 to take the bolts off and torque setting #1 to torque down the new blades on my XT3GSX with 60" fab deck. If you can't spend the cash on a new one check the pawn shops I've seen them. Post #26 is a pic of mine. I also use it to rotate the tires on my truck and cars and buggies. Quick and easy.
 
#31 ·
While I still use the HF electric impact, I recently picked up the Milwaukee M12 ⅜ inch impact wrench. With the 117 ft lbs of torque, it works for just about everything from taking the nuts off the deck of the XT3 GSX to other odd jobs like sinking lag screws.
 
#32 · (Edited)
I don't have much to add, other than to reinforce a few things already mentioned.

Torque wrenches are only for tightening. Preferably for the final torquring only (not the full install).

6-POINT socket is a must, regardless of wrench/tool used to turn it.

Old school, block of wood, with a breaker bar (and cheater pipe if needed). Cheap and fairly easy.

HF electric impact wrenches are cheap and effective. I bought one to remove lug nuts on my RV (which were undoubtedly installed using an air gun at the tire shop).

Battery power is ideal if/when you can afford it. I finally broke down and started buying the Milwaukee M18 Fuel tools last year. I only have the 1/4-inch impact so far. It's struggled with a few things, but its lack of power helps keep me from destroying stuff, LOL...

Mike
 
#33 ·
I've seen a few people above advise to not use an impact to remove nuts. I don't know why that would be. My shop mechanic uses Milwaukee impacts to do everything. Including removing lug nuts on skids/trucks/loaders. Never had a problem with damaging the impacts.
 
#34 ·
I don't believe they were advising against using an impact to remove nuts, but that people shouldn't use a torque wrench (totally different) from removing nuts.

You can physically damage the measuring mechanism and/or mess up the calibration by using it to remove nuts/bolts (or by applying significantly more pressure when tightening a nut/bolt than it is set for).
 
#35 ·
Torque wrenches are made to tighten a bolt to a specific torque value. They aren't made to loosen bolts. When your torque wrench isn't in use it should be set back to 0 torque value on the wrench to preserve its accuracy and internal components.
I'm still using my Dad's torque wrench that is atleast 50 yrs old. It is a stainless steel Sear Craftsman and it is still accurate because it has been maintained and stored properly. I also have his in/lb. torque wrench in the same quality condition.
Impacts, electric, air and cordless are widely used in the professional industry on a daily bases with 6 point impact sockets in all commercial settings. Then followed with a torque wrench for settings the final torque value.
A variable setting torque wrench is recommended to be versatile for a wide range of specific jobs.
 
#41 ·
I agree with the setting a "click type" back to zero, it unloads the beam inside.
But, as for the accuracy, have you ever checked it?

I also have a old C-man click type that I bought new in the 70's. My 1st tool out of HS.
Some years later, I worked as a tech in a diesel engine development group, building and testing engines all day.
Early on, many of us used our own torque wrenches, until the shop bought a bunch for everyone to use.
Anyway, because we cared about accurate torque on fasteners, we would have our wrenches calibrated by the factory inspection department.

Based on that, I can say that,
1 - "click type" wrenches are not linear, (at least the wrenches we had, which included several common brands) meaning they don't match the setting value from zero to max, and in fact the slope is different so at one end it is above desired value and on the other it's below. (not sure which way off hand). There is only 1 point where the actual value matched the setting value.
2 - they do change with time or maybe use, (not sure which) - we would check them every 6 months or so. (I suspect, but don't know, that the tapered point on the end of the beam wears causing a shift in the "break point".)

On mine, I taped a small piece of paper that indicated the setting and actual torque values.

When your torque wrench isn't in use it should be set back to 0 torque value on the wrench to preserve its accuracy and internal components.
I'm still using my Dad's torque wrench that is at least 50 yrs old. It is a stainless steel Sear Craftsman and it is still accurate because it has been maintained and stored properly.
 
#36 ·
As to using an impact overall... ya. Some bolts are specifically recommended not to, others it doesn't matter. One way of thinking is that if it needs real heavy guns to remove it, maybe the heavy guns used to install it were... too heavy. Either that or it's been on there for a long long time, and nature has welded it.

As with lug nuts, blade nuts are often over-tightened. There is a torque spec that should be adhered to, anything more is asking for problems later on down the road.

Personally I prefer a smooth even wrench pull, without the impact induced shock which could potentially leave a busted stub to remove. I know lots of guys get away with it, sure. But for each time you overstress and stretch a bolt you increase the chances a five-minute job will turn into an all-day job.

I know everyone's mileage varies, but that's what I do. Big hammers for big Problems only.
 
#37 ·
In my experience, the battery-powered impact wrenches are useless as impact wrenches, the best they can do is drive a nut that has already been loosened.

The funniest experience was when some kind of either salesman or marketing guy came up to me at racetrack pits to show their latest and greatest lighter smaller impact wrench, showing it off by comparison with a heavier more powerful one. So OK, let's try it! And... the smaller impact wrench couldn't undo a lugnut. Try the heavy one, that was supposed to be "too much for the job", and... it couldn't undo a lugnut either!

What I generally see is that they're way overrated. Later I've owned a battery-powered impact wrench rated at 250 lb*ft that couldn't undo the nuts tightened at 100 lb*ft. Worked great at driving the lugnuts after they've been loosened though :) The other way around, it didn't tighten to 100 lb*ft either but it left just enough slack for the final tightening with a torque wrench.

The air-powered impact wrenches work much better but the rule of thumb is about the same: pick one rated at 400 lb*ft if you plan undoing 100 lb*ft nuts. Harbor Freight has a good one rated at 700 lb*ft.
 
#40 ·
I can see where the confusion comes in as a torque wrench and an impact wrench are often called the same thing. Torque wrenches have a scale to determine torque when tightening a nut. Impact wrenches have a maximum torque value. Another way to look at it is that a torque wrench is a precision tool where an impact wrench often uses brute force.
 
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