How sharp do you guys sharpen them? I think it’s time to reduce dullness a bit.

And another thing. My first shredder (Howse, I think) had blades that dulled quickly. I sharpened them a lot. This shredder (Bush Hog) must have tougher steel blades, because after years and heavy use, they aren’t real dull. Is tougher shredder blade steel a thing? I’m not knowledgeable in this area.

I never sharpen them. Sharp shredder blades tend to make clean cuts on the little sapling stumps and then punch a hole on a tire on UTV's and ATV's. A duller blade will leave them feathered rather than sharp. That's what works best for me anyway. I'm sure others sharpen them frequently.

If I felt the need to do it though, I would pick it up with a chain and my bucket and then use an angle grinder.

Hmmm...following this thread as I was thinking the same as 603...but after seeing Trappers post, maybe I don't need to sharpen?

I use an 80 grit flapper wheel on my mower blades. I would imagine it would work on a shredder as well.

I dress mine up occasionally keeping about a 1/16 edge using an angle grinder. A little bit goes a long way and you DO NOT want to kill the heat treat on the blades by being over aggressive gtinding.
When mowing pasture grass i keep the shredder box almost level. and when shredding I do the same to avoid or mitigate jagged edges.

If I sharpened it I’m sure it would cut the grasses better but it does it to my satisfaction. I just don’t want the sharp little ash and elm stobs. My Service Rhino SE5 is 20 years old and has never been sharpened.

I went ahead and did some sharpening on the blades. Hard to find words to say how sharp, but it’s no longer as dull as it was. No way you could cut yourself on the new edge, but it should go through dry grass better.

I used to have to crawl under the lifted shredder to sharpen, but now I have a hydraulic upper link and can sharpen standing up. Such a big improvement.

Depends on what you want to cut/shred.

If mostly grass, weeds, vines and very small saplings....then I like to keep the blades close to what the factory (new) profile was.

IF you are wanting to knock down hardwood saplings 1.5" to 2.5" then a bit duller blade will 'shred' the left over stump/stob more and make it less likely they will try to repopulate.

I've never had a sapling 'cut' so well that it posed a threat to tire punctures....but I run heavy ply tires on everything I own anyway (because of Honey Locust Thorns).

I looked under mine out of curiosity a couple of years ago and I parked the tractor on my pond dam with the deck hanging off and I thought about how easy it was be to sharpen blades with it just hanging off into space like that,

I use 40 grit Diablo discs and keep them sharp, it’s a lot easier on the equipment when they cut better but I’m OCD with all my iron so some guys might find my methods excessive.

Some shredder blades are made out of better steel, if their tough to grind that’s a good thing and probably made out of something like AR400 where the easy to grind blades are made out of junky mild steel. Never replace the blades with the cheap junky ones either, you get what you pay for with these.

I do a lot of shredding, I never sharpen blades. I do replace them about every 6-8 years.

Mine are due for a touch up. Like said above, don't get them completely "sharp". You want to leave a 1/16"-1/8" blunt face on the edge. A sharp edge will roll over when it hits something substantial, then it's worse than it was before you went thru the effort.

I have two shredders, a Modern Ag 10ft and a Woods brand 6ft "Bull" with a 4" capacity cut. I will sharpen the blades on the 10ft one with a 4 1/2 grinder , because I use it for mowing and it will leave strips of uncut grass when it gets real dull( I think it bends the grass over). The 6ft shredder, I had to replace the gear box in it a few years ago and I put new blades and a stump jumper on it, but I have never sharpened the blades since.

I do change the oil in the gearboxes ever couple years and keep them all greased up real good. I keep an eye on the gearbox shafts underneath and make sure no wire gets balled up around them, I ruined the gearbox in my shredder because it sucked up a strand of wire and pulled the seal out.

We shred some thick, tall grass every year and the difference between old, cut up, well rounded blades and new ones is significant. We can cut at a faster ground speed and less rpm (think, less wear on the machine) with new blades. We replace ours every 2-3 years. Hit them with an electric grinder before each season..

I’m using a Diablo flapper disk (40 grit I think), and it is not worn out, but that steel was tough. I guess it’s the good steel, which is lucky for me, and I guess that’s why the edge held up so long. I didn’t take off much metal.

When we bought the place, and I had never shredded it, I ran over all sorts of blade notching stuff. Now though, there are rarely any surprises, other than the grass and weeds being real thick and tall. The first time I shred each year, the grass/weeds are as tall as the tractor in places. The bigger tractor and more HP comes in handy.

Or hay string/netting hidden in the grass. It will ride up on the shaft and ruin a seal also.



Took me about 1/2 hour with a razor knife to remove this mess!

I quit fighting with gearbox seals on shredders long ago. I use red high temp axle grease in my gearboxes. I see others recommending cornhead grease.

This was discussed some time back, when I found the shredder gearbox empty of gear fluid. I replaced it, and that leaked out quickly. It was suggested here to use grease instead of the gear fluid. I did that with John Deere Corn Head grease, which also leaked out. Then I used a some more of that and some Mystic red sticky grease. I guess it was about a 50/50 mix. Not losing any grease now.

I tried it with some high temp grease but the bearings done swelled up and spun the races. New gear box was 600.00.

Instead of grinding to sharpen take your blades to a blacksmith and let him beat the edge back with hammer or some have a trip hammer.They also know how to heat treat for a longer lasting edge.

I keep 2 sets of blades. When I think it's time I'll pull them off, replace with the other set, and reshape the leading edge of set #1 in a vice with a hand file. Rinse and repeat. Hand filing a shredder blade is amazingly therapeutical.

I use cornhead grease.

How much grease do you put in the gearbox?

I have the mixed grease level up to the gear box weep hole. I check the level by removing the top plug and using a plastic stick as a dipstick. It seems that the mix of Corn Head grease and the mystic Sticky Red grease keeps the leakage down. I guess my leak is a bit too much to get by with just the Corn Head grease. And probably just the red Mystic grease would work fine by itself, but I wanted at least some of the less viscous Corn Head grease in there to thin the mixture up a bit. No science here, just guesswork.

Corn Head grease liquefies some as it heats up. So it will also seep past seals that are worn or a shaft that has a 'groove' in it. Not as bad as gear lube...but it doesn't stay the same viscosity as you see it in the tube.