Hi troops,
I started to change the blades on my Scag Tiger Cub 48" deck today and ran into a problem. even with a 400FTLB impact wrench and the air compressor at max pressure, I couldn't remove the nut on the R/H blade bolt. I had to drill small holes progressively on opposite sides of the nut and took a chisel and hammer to split the nut to remove it. The blade on this spindle was in worse condition than the other two and I think that from striking rocks, roots, or other not easily moved objects, the bolt tightened excessively. I damaged the bolt in the process of drilling the nut to split it so I had to replace both. I have the nuts here in my parts stash but not the bolt, Scag dealer stocks them and told me that they are a common replacement part. I put a thin aircraft type washer under this nut in hopse that it will prevent what happened, time will tell!!!
I have to raise up this machine considerably in order to get the blade bolts to clear the bottom of the spindles and fall out. My hydraulic floor jack just makes it high enough as long as I add a piese of 2 by on the lift plate. Not crazy about that combination so I put my adjustable jack stands under the machine before I crawl under it.
Mad Mackie in CT:biggrin::laughing:
I had this on one of the blade spindle nuts on my 61" Tiger Cat SS. Ended up taking my mower to a local truck repair shop and they used a 1" drive air wrench. Spun that nut right off.
I replaced all three nuts and put a bit of lube on them. Only tightened them by hand this time. Seems to work now...I can remove them.
Worked at a repair shop several years ago and had a Ferris come in that the blades bolts went all the way through the spindle with a nut on top. You put the nuts on finger tight and took an inch impact to remove them. 900 ft/lb 3/4 impact wouldn't touch them.
I have never run into to this. I have always been able to use either a breaker bar and in more recent years a 1/2 inch impact wrench. I also have a 3/4-inch impact and hope I never have to use it for this application. I always assemble with anti-sieze, so far so go.
For everyone out there. It is a good idea to use anti sieze on all nuts and bolts that are exposed to dirt, grass, and moisture. Our procedure is to do it on all blade nuts and bolts, plus anything that gets removed for normal maintainence. Really makes it easier down the road, or cheap insurance as we call it.
Anti-seize is good stuff but if using it on thru bolted blades I wouldn't tighten the nuts to 75 FT LBS. The use of anti-seize makes it a wet torque and overtorquing the nut will happen.
Tomorrow I need to do a 50 HR service on my Tiger Cub and I'm going to replace the blades, hopefully the blade nuts will loosen with my 400 FT LB impact wrench. I also need to replace the blades in my wood chipper as I unknowingly put some stones thru it. I use anti-seize on the flush allen bolts on these blades. I periodically need to remind myself that it is a wood chipper and not a rock crusher!!!:frown:
Mad Mackie in CT:biggrin::laughing:
I'm going to reduce the torque to 50 FT LBS also, but tomorrow I'll see, these blades have been on since last falls cleanup and I don't usually leave them on that long, getting lazy!!!! Gotta do something with the L/H brake band also!!!
Mad Mackie in CT:biggrin::laughing:
#9
Coyote Machine
Just did the three blades on my Wildcat. Prior Pro owner had grey anti-seize on the spindle bolts but they would not budge without a 1.5' breaker bar and a pipe 'cheater'. Thought the breaker bar might break, but it didn't - fortunately. Called my dealer to make sure, before using the cheater pipe, that the blades weren't reverse, (left hand) thread. Evidently they aren't! The shop owner, a Scag dealer, told me he often has to use a Dremil tool to cut off the top nut to change/sharpen blades.
So I wire wheeled the spindle bolts threads and applied a light coat of COPPER anti-seize, and torqued to 75 ft lbs.
I have found that the copper anti-seize works best- I usually use Wurth brand, from when I had my foreign auto shop. It is a German manufacturer of high-end parts for the automotive trade, and their products are excellent, though pricey.
I do agree about wet torque and its adverse effect of possibly skewing the actual torque amount- but we'll see what the outcome is when I next attempt to remove the blades.
I may like some have mentioned consider lowering to 50-60 'lbs in future if I find the nutz too tight again. I'd rather have them somewhat over-tight than loose. Any further discussion of the 54'lb torque appreciated.:thumbsup:
At my last blade change not long ago I decided to not use antiseize but I did install a thin 5/8" aircraft type flat washer under the nuts and torqued them to 75 FTLBS.
I have had to drill off several of the blade nuts in the past. I drill two rows of holes in a radius pattern 180 degrees from each other and split the nut with a cold chisel. I use an air drill and cobalt drill bits.
I would torque the bolts/nuts to no more than 50 FTLBS if using antiseize and possilby as low as 40 FTLBS.
I usually change blades 3-4 times a season so I don't run into the corrosion problem that can set into the threads. It has been the R/H blade nut that I've had to drill off and that blade is always the most worn when I inspect them and usually past the point of being resharpened. I buy aftermarket blades in bulk on line very reasonably and my blade sharpener doesn't get used very much any more. I keep at least one new blade bolt and three nuts in my parts stash.
My dealer gave me a "blade Buddy". I studied the directions for it & found it useless. The bolt & nut need to be held & or turned. The blade holder in my opinion is useless. I use a breaker bar & a air driven impact.
if it helps anybody I use a 1/2 impact wrench to remove the nut on top and then a rubber mallet to give the bolt a couple of soft blows to make sure it drops to the floor
Yikes, When you guys with all the experience and multiple examples speak the rest of us should listen. Sounds like the torque tables and lubricant guidelines in this forum somehow don't apply in this case. Wonder why none of the bolts do not work harden and just snap? Seems like the bolts would show some "twisted" grain visible near the head.:confused2:
Edit: For you machinist types. Do you suppose Scag is using too tight a thread "class." That is a thread when engaging feels really snug as it threads into the mating part? Good lubricants would ignore this close fit and work anyway? Just say'n...
#14
reynoldston
Got to say I never come across one I couldn't get off? I work on customers mowers and think some of them the blades have never been off. I do some times have to use my 36 in breaker bar and some heat.
I've only had one Scag blade bolt to be unremovable. After that, I started using anti-seize on the bolts and taps and I've never had a problem since. I've never even had to use a breaker bar when using anti-seize.
As far as torqueing the blade bolts, I've never worried about that. The first bit of heavy grass that you mow is going to run the torque way past 100 foot-pounds anyway.
Also Mackie, there's an Agri-Supply store near me that sells those blade bolts much cheaper than the Scag Dealer. They are simply a Grade 8 bolt of the correct length and diameter. I've forgotten the exact length.
