Impact Wrench or not?

[gps_jetskier]

Managed to wack myself in the head with the rachet this weekend changing the blades. :dizzy: Smart move I know. I'm fine, but it's got us to talking here at work. Do you change your blades with a impacts? I've taken them off that way, but I always read to put them on with a torque wrench. I always use a big ol rachet.

[mowerconsultant]

I have a compressor and impact and use it to remove them, I put them back on with a ratchet and torque wrench.
That is what I suggest.

Pj

[DiezNutz]

I have a compressor and impact and use it to remove them, I put them back on with a ratchet and torque wrench.
That is what I suggest.
Pj
I agree. You just cannot control the installation torque of an impact wrench with any precision unless:
(a) you have a "torque stick" made the same as the blade bolt torque
(b) you use the same impact wrench all day every day and with much experience have developed a calibrated "trigger finger" :)

This is one of the reasons I never take my vehicles in for even new tires... I'll always take the loose wheels in.

[gps_jetskier]

I see the manual says to torque them to 118. Anyone really do that or just ref on em till they're tight?

[Mower For Less]

I have been using a impact to remove and install my blades for the last 4 1/2 years without a single problem. You can get torque extension bars for your impact that limit the amount of torque it can impart to your fastener (common in automotive applications, mainly for installing wheel lug nuts) if your concerned about overtorquing.

Kevin

[gps_jetskier]

I am since I had a buddy nearly have to torch his spindle off from them being installed too tight with an impact. Maybe I'll look into the torque sticks....

[wrightg4]

After my first experience using a torque wrench (upside down) and 2 X 4's to block the blades, I started using an impact wrench to remove and install the blades on my Fastrak 44. There's no need to lock or block the blades to keep them from turning. The impact wrench loosens and tightens them quickly and easily. I've used the wrench in combination with a 120 ft/lb "torque stick" to tighten them, however getting sufficient clearance for the impact tool and 8" long "torque stick" has been a challenge. I've been backing the mower up on a set of ramps, and using a floor jack and a 4 X 4 block of wood to lift the front in order to get the combination of wrench and stick under the mower. Anybody have an easier, quicker way to gain the needed clearance?

[DiezNutz]

... You can get torque extension bars for your impact that limit the amount of torque it can impart to your fastener ...
That would be the "torque stick" I was referring to. If you could find one that was 120 ft-lbs, that'd be close enough. They're not cheap though.

I use a torque wrench. My impact will do 600 ft-lbs, I don't trust myself with it.

[KUBOTADAN]

That's all I use. I tighten on the lest selectionso not to strip a bolt. No problems.

[Mower For Less]

That would be the "torque stick" I was referring to. If you could find one that was 120 ft-lbs, that'd be close enough. They're not cheap though.

I use a torque wrench. My impact will do 600 ft-lbs, I don't trust myself with it.

Yes sorry, due to the delay between posting and when they appear due to moderator approval, I did not see your post when I made my reply. Snap on has just the "stick" you need. Here is a link to the exact item, its $35.

http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=78291&group_ID=2219&store=snapon-store&dir=catalog

Also, on a technical note, just because your impact wrench is rated for 600 lbs., that dont mean it will really put 600 lbs on it. My Ingersoll Rand impact wrench is one of the best 1/2" drive impacts you can get, and it is rated 400 lbs forward and 600 lbs reverse. However, if I run a bolt down and let it keep beating on it until it absolutely does not get any tighter, I highly doubt there will be any more than 200 ft. lbs. of ACTUAL torque on that fastener. And I have a 3/4" drive snap-on torque wrench with a dial that reads torque in both directions up to 600 ft. lbs, so I can easily check that and verify it. I can also attest to I used to work in a shop where we used 3/4" drive impact wrenches rated at 1200 ft. lbs. forward torque, and we assembled a component that needed to be torqued at 400 ft. lbs. We would beat them with the impact, and when we put the real torque wrench on them, we would always get a little more movement before it clicked, they were probably about 300-350 ft. lbs. off the impact alone. Its kind of like in the olden days when auto manufacturers used to pick their own horsepower ratings before standards were imposed.

Kevin

[DiezNutz]

Also, on a technical note, just because your impact wrench is rated for 600 lbs., that dont mean it will really put 600 lbs on it...
I basically agree w/ everything you said, I was being more figurative than literal. IIRC my impact is only about 400 lbs forward as well. Of course no impact wrench actually supplies that in actual torque, it's a torque equivalent resulting from the rotational "inertia" imparted to the fastener by the tool. Poor man's impact wrench is a box wrench (or solid breaker bar w/socket) and a hammer, and can perform wonders that alot of straining in the form of pure torque cannot. :)
I guess my point was really about how you can't really control it all that well. To borrow from your example, if you happen to know your impact is going to give you the equivalent of 200 ft-lbs pretty consistently by beating down on it, exactly how much do you beat down to get 118 ft-lbs (without benefit of a nifty dial gauge)? Or, in the process of not wanting to over-tighten it, you quit before it's actually tight enough? Takes a fair amount of practice/experience with your impact to "feel" that 75% or so yield point, and I'd hate for someone to get overzealous with some King Kong impact and gall threads, maybe even shear a bolt during the learning process (possible, if it had corrosion and/or stress fractures already), or potentially even worse have a blade come loose.
That's where the torque stick gives you the best of both worlds.

P.S.- The golden rule my gearhead buddies and I have used for years is: The correct torque for any fastener is precisely a quarter-turn before it snaps :laugh:

[gps_jetskier]

Anybody have an easier, quicker way to gain the needed clearance?

PM me. I build a jack system for the front end that works really slick. Rev two would be even better.

[puppypaws]

Managed to wack myself in the head with the rachet this weekend changing the blades. :dizzy: Smart move I know. I'm fine, but it's got us to talking here at work. Do you change your blades with a impacts? I've taken them off that way, but I always read to put them on with a torque wrench. I always use a big ol rachet.

I have used an electric impact for many years with absolutely no problems. I have a feel for the tightness, once it starts to bang I stop when tightening. I have never checked the torque, it is a feel thing you become familiar with.

People don't realize the vibration from the impact works at loosening the blade bolts so much easier than steady hard pressure.