getting the blades off

jima1 · Dec 28, 2002

My wife surprised me at Christmas with some beginner air tools /w3tcompact/icons/smile.gif, it's the <A target="_blank" HREF=http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=33567> Central Pneumatic set from Harbor Freight </A>

The first useful thing I thought to try it on is taking the blades off my KK 5' rear mower. The deck is at least 10 yrs old, I just bought it used a little over a year ago, this is my first attempt to get the blades off for sharpening. Cannot budge the bolts with 15" breaker bar, so I was hoping the impact wrench would make this job easy, even though it is low end. However, it just hammers real good, won't break loose. /w3tcompact/icons/frown.gif I'd appreciate some suggestions on what to try next.... /w3tcompact/icons/hmm.gif is this wrench too lightweight for the job?

Again, I'm a total beginner with air tools, and I've never had this mower apart either, probably there is something I'm doing wrong. My old Worthington compressor is small but it seems to hold 90 PSI ok. I did make sure the wrench was going in the reverse (loosening) direction...

Thanks,
Jim

JohnMiller3 · Dec 28, 2002

...Cannot budge the bolts with 15" breaker bar,...

I'm assuming you're using a 3/4" socket set... use a 3-4' pipe on your breaker bar as the extension... and the laws of leverage works in your favor... /w3tcompact/icons/smile.gif

On my KK... I believe they were torqued over 500 ft. lbs. on the blade bolts... short of using a super 3/4 or 1" drive air impact wrench... I've never seen anyone's 1/2" impact wrench take those nuts off... /w3tcompact/icons/blush.gif

usedcarz · Dec 28, 2002

if you have access to a torch, put a LITTLE heat on the nut and then spin it off. i had same problem on my kubota and on the king kutter mower also. i took them into my shop which compressor carries 180 psi versus mylittle unit at home. the big ole psi made the difference real quick, zipped them both right off. but the heat will work. just don't want to get hot enough to damage any seals or bearings in the hub units. even a little propane plumber's torch would get it hot enough to make a difference.

normde2001 · Dec 28, 2002

That would require a bigger impact wrench. Your is 230ft/lbs max and those bolts are probably 500-600ft/lbs or more plus corrosion. I would soak them in "PB Blaster" and find about a 3' pipe to fit over your breaker bar. An impact wrench big enough to handle that job would cost $200-$300.

jima1 · Dec 28, 2002

Thanks for the suggestions guys, I guess my new toy is not up to the task....I'll go shopping for some heat, PB blaster, and pipe, they've got to be a lot less than the big impact wrenches, I don't have enough uses to justify that.

Jim

rdbrumfield · Dec 28, 2002

Heat is the best answer, at least that has been my experience. Melt some bees wax on them if you have any, you will be amazed.

em14 · Dec 28, 2002

I have never heard of melting Bees Wax on a rusted nut and bolt to help loosen them ... what does this do? This is a new one on me ... Does the wax melt and then penetrate the rust?
Leo

Anonymous Poster · Dec 28, 2002

Please don't take this wrong..! Are they left hand threads, my woods was. George

Bird · Dec 29, 2002

Jim, that's a nice little set of wrenches for a lot of jobs, and I've owned and used quite a number of Central Pneumatic tools myself. However, compare the 230 ft./lbs of torque the cheap impact wrenches produce to the 425 ft./lbs. of an Ingersoll-Rand IR231 (quite possibly the most popular impact wrench in the country) and the Chicago Pneumatic CP734. The IR2131 even tightens to 450 and will break loose up to 600. Those are all 1/2" air impact wrenches that use 90 psi air pressure but the performance varies greatly, and of course, the price increases with the performance. I never found a mower blade that my IR231 wouldn't take off, but if I were going to do a lot of work with an impact wrench, I think I'd have to spring for an IR2131.

JimMc · Dec 29, 2002

Just as an indication of what you're up against, during production of our cutters we use a 1" drive impact for assembly of the blade bolts, and then follow that up with a torque multiplier/torque wrench. Our line pressure at the gun is regulated down to 120PSI and our tank pressure runs about 180. Of course, we don't just keep hammering with the impact gun, that would over torque the bolt, but it's still more than the average 1/2" drive gun will remove.

rdbrumfield · Dec 29, 2002

I too would have laughed if I hadn't seen it for myself. An old timer gave me the hint when I was trying to get a broken stud out of a block. I had drilled and was using an easy-out and it wouldn't budge, even after heat, he shobed that bees wax in and when it cooled it came right out.
Bees wax is what was used to make molds in the days of pyramids.

jima1 · Dec 29, 2002

George,

That's a good thought, having broken a left-handed lug on a mid-70s Plymouth /w3tcompact/icons/blush.gif you can be sure I won't take your post the wrong way!

Before I go try it, I might as well ask: any KK owners out there who could confirm left-handed threads on blade bolts?

Thanks,
Jim

jima1 · Dec 29, 2002

Bird:

Of course you are absolutely right, for any serious work I would expect to move up to something a lot more powerful like the IR2131. But outside of tractor upkeep, my needs are very modest right now. Being new to air tools, I'll use the cheap set to gain some experience and see where that leads before springing for the $200 model /w3tcompact/icons/smile.gif.

Thanks for your comments!

Jim

OkieG · Dec 29, 2002

Don't be oblivious to the adverse effects of cranking up the psi to coax more performance out of your air tool.

At a local tool warehouse, I was looking at a big (to me) IR 3/4' drive air wrench. I asked the salesman about psi and was surprised to hear that even the "big" tools are mostly rated for use at 90psi. Before becoming a salesman he used to rebuild air tools for a living. He said folks that turn up the psi on their tools is what kept him in business.

Larger air tools may have a higher torque rating, but may require higher air flow (cfm not psi) for optimum performance. A small portable compressor (like mine) generates ample pressure, but the flow is weak for larger tools. It is pitiful with my small sandblaster!

A drop or two of oil each time you use your tools will help them last longer.

Welcome to the world of air tools. Enjoy!

OkieG

jima1 · Dec 29, 2002

JimMc:

Thanks for the warning! An experienced friend offered to stop by with his 3/4" air wrench, hopefully between that and the other suggestions it will come off.

Jim

Bird · Dec 29, 2002

He said folks that turn up the psi on their tools is what kept him in business.

Yep, George, that and failure to add a little air tool oil (preferably after each use), failure to keep oil in the impact mechanism of those that use oil or grease in those that have grease in the impact mechanism, and getting dirt and moisture into the air intake./w3tcompact/icons/grin.gif

You may be new enough to the forum to not know that I was in that business for about 3 years; found it to be very interesting and a lot of fun. I don't know of a single 1/2" or 3/4" impact that isn't rated for 90 psi (not to say that such doesn't exist 'cause I ain't seen all of them yet; just most of'em), but a lot of mechanics are running 150 to 175 psi , and if you need that extra power, maybe it's worth a repair or replacement bill now and then./w3tcompact/icons/wink.gif

beenthere · Dec 29, 2002

I agree and was also amazed when I watched a mechanic prepare an engine block for steam cleaning. After experiencing removal of studs in engine blocks and getting a few that would just twist off, I made a smart remark about how he handled such a problem. He said, just you watch.

He grabbed a torch (acetylene) and heated the studs quickly to almost red, then touched them with a wax candle. He then took a pair of light weight pliers and easily turned the studs out. Truly amazing! The wax seemed to wick right into the threads as the bolt cooled (likely also cooled due to the wax). Someone might know the physics behind this trick, but I watched him do several studs and they all came out very easily.

em14 · Dec 29, 2002

Very interesting ... thanks
Leo

JimMc · Dec 29, 2002

3/4" drive should do the trick.

Just another tip - use 3/4" sockets not just for the strength factor. Every time you add a joint, whether it be for an adapter or extension or whatever, you lose effectiveness in an impact tool application. Even a loose fit in the socket reduces the imact effect.

Also, I think you'll find that KK uses traditional RH threads on their blade bolts.

One last tip. Always replace the lock washer, even if it is brand new. They are not made for re-use. If the lock washer cracks on re-installation, it has no locking action whatsoever.

OkieG · Jan 2, 2003

mechanics are running 150 to 175 psi , and if you need that extra power, maybe it's worth a repair or replacement bill now and then.

No, Bird, I didn't know you were "in the business". I find your opinion on using higher pressure interesting. I guess if you know how to fix 'em it broadens your point of view.

I went ahead and bought the 3/4" IR-261 wrench I was looking at (on e-Bay). I think I got it at a fair price, but it was still almost $300.

A lot of places sell impact wrenches, but I wouldn't know where to look to get one fixed. Does it cost much? It must be cheaper than buying a new tool. Could the average user do it himself? Where do you find rebuild kits?...from the manufacturer? How well does a reasonable quality tool hold up to 150-175 psi? I'm wearing out the question mark key, so I'll stop now. Thanks.

OkieG