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06/09/2009: "A Tough Nut To Crack"

Time is gettin' on at the farm, and the weeds and blackberries are a-growin'... I've been trying to get the rotary cutter, AKA bush hog, ready for use before the weeds have all gone to seed. Job 1 has been getting the blades on this cutter sharpened. When Grandpa Dennis was in town a couple of weeks ago we took an ineffectual run at getting the blades off - it turns out that it is not sufficient to just jack it up and crawl under there with a crescent wrench! My back up plan was to file the blades in place, but that was laughably naive - the blade edges were as round as your finger. Grandpa Dennis immediately recognized that we were in a tougher spot than I suspected, and we went home to regroup.

I called the John Deere dealer for advice, and they were kind enough to educate me on how to go about getting the blades off. First of all, it turns out that there is an access port in the top deck, through which you can get a socket on the 1 1/2" nut. This next picture is jumping ahead of the story, since one blade is clearly off in this photo, but you can see the access port near the upper edge of the picture as an oil-soaked hole. Why oil-soaked? Because on the next several trips to the farm I was dribbling Liquid Wrench onto the blade nuts and bolts like it was holy water.



So, the escalation of this process went like this:
Crescent wrench
1/2" electric impact wrench
1/2" breaker bar
1/2" breaker bar with Liquid Wrench
1/2" breaker bar with Liquid Wrench and FOUR foot pipe cheater

Still wouldn't budge! OK, so at this point I knew I was dealing with some tough nuts. Reaching way back, I recalled some of the extreme measures recommended by John Muir in the Compleat Idiot's Guide to Fixing Your VW. Next on the list was going to be heat.



Voila! Success on the first bolt... the heat, the Liquid Wrench, the four foot cheater pipe did the trick. Now for the second bolt... sprinkled the oil, tapped it for vibration, tap, tap, tap, wait a while, heated it up, scramble to get the blade under the access port, get the socket and 1/2" breaker bar on it, slip the cheater pipe over the breaker bar, push, push, harder, harder, HARDER... oops, twisted the drive shaft right off the breaker bar! Dang, that cheater pipe applies some serious torque. Done for that day.

Next trip I'm back with $96 worth of 3/4" breaker bar/extension/socket from Sears (3/4" tools are spendy). Go through the same drill... only to find out my cheater pipe is too small to slip over the 3/4" breaker bar handle. Done for the day, again.

Next trip back with a bigger pipe. Also, on the advice of a colleague at work I took the precaution of buying a MAP torch (the ones with the yellow canisters). They burn hotter, which would allow me to heat the nut faster without allowing time for the heat to propagate to the bolt - the idea is to maximize the differential.



The same mad scramble: getting the bolt heated hot, hot, but not too hot... rotating the blade into position... getting the socket and breaker on it... getting the pipe cheater on the breaker bar... push, push, PUSH. And finally it gave, the nut loosened.

Still, the drama was not over. I had to continue to use the breaker bar to unscrew the nut - it was on that tight. At some point I was clumsy in lifting the breaker bar to rotate it 90 degrees for the next push, and I knocked the socket off the extension. Clunk, I heard the heavy socket hit the ground. Peering down, I couldn't see the darn thing. I finally had to crawl under the cutter, and reach over the mound of dirt that some ground squirrel had pushed up under there so I could feel around for the socket. I couldn't find it! But the ground was a bowl on the other side of the mound, so I reached down into the squirrel's burrow hole... there it was a couple inches below the surface! If the socket had been any smaller no telling how far down the burrow it would have tumbled.

So, now I'm cleaning up the nuts and bolts at home in the garage, and filing the cutting edges of the blades. It's slow work, but I've got one blade done and the other started. Next week I'll re-install everything on the cutter and get to work out in the pasture.