Should I sharpen my brush hog blades?

[James D]

I have a Woods 42 inch brush hog That I use with my Kubota B1750. The blades are so worn down that the front edge and the back look nearly the same. The dealer said that I would do better to replace them than to sharpen them. He gets $115 for the pair. The mower was well used when I got it, so I don't know how much mowing it took to wear them this much. I cut mostly grass with lots of brush, vines, small limbs and other junk mixed in. I never owned this kind of mower before so I don't know what is best. What would you experienced guys do?
Thanks.

 

[lugbolt]

they can be sharpened-and they do cut better, however sharpening shredder blades is an excercise of patience. Takes a while if they're "that" dull.

 

[85Hokie]

Now a brush hog and a finish mower have two different thoughts when cutting:

A hog will cut damn near anything in it's path - rocks, roots, grass, that old bucket that you lost ....etc

A finish mower should only cut grass.

The hog has an edge that you could run your finger down and not worry about being cut, the finish mower should cut you good fashion if you did that!

 

[StephenR]

I sharpen my bush hog blades when I use it a lot. After a few cuttings I will prop it up and do an inspection.
My lawn mowers get sharpened at least once or maybe twice a year. Depends on how much mowing we do through the year,

 

[SDT]

I have a Woods 42 inch brush hog That I use with my Kubota B1750. The blades are so worn down that the front edge and the back look nearly the same. The dealer said that I would do better to replace them than to sharpen them. He gets $115 for the pair. The mower was well used when I got it, so I don't know how much mowing it took to wear them this much. I cut mostly grass with lots of brush, vines, small limbs and other junk mixed in. I never owned this kind of mower before so I don't know what is best. What would you experienced guys do?
Thanks.

I use all of my rough-cut mowers as HD finish mowers and keep the blades sharp. Sharp blades cut considerable better and require a bit less power and fuel. Yes, I go through blades much more quickly than do others because I dress them after nearly each use.

Do not sharpen blades if you routinely hit rocks or other debris, clear land, or cut saplings. Saplings cut with sharp blades are much more likely to puncture tires.

If your blades are as dull as you describe, I would replace them rather than trying to sharpen them.

 

[Jim L.]

If the blades are sharpened, can they be balanced?

Recommended to change the bolts for the blades because of the torque when tightening them.

 

[GreensvilleJay]

Buy a second set, sharpen the 1st, then swap every month or so depending on how many hours you cut 'grass'.
Yes, they can be balanced, simply weigh them, then grind some off the heavy one.
A balanced machine will last longer, less 'wear and tear' due to vibrations.

 

[chim]

I'm no expert. Had a five footer years ago. I have seen some posts here and elsewhere that made some sense. One suggested that if the hog was used for whacking saplings and such that it was best NOT to make the really sharp. Thought was the blades would make punji sticks that would cause flats.

 

[Russell King]

Here is my experience with the blades on shredder that was purchased used.

The property is flat with mostly tall grass and weeds. There are a few small saplings that get cut but less than one inch diameter. There were quite a few limbs on the ground from deadfall. I mow about 3.5 acre. I mow maybe 2-3 times a year.

The first time I mowed I used the blades on the mower as they were (pretty dull and banged up). I mowed high (10 inches) the first time and then lowered it the next time to about 5 inches. There was a lot of clean up done and the blades took some damage hitting the limbs. I then bought new blades and purchased two sets (off the internet) and replaced the blades on the mower.

I compared the new blades with the original blades and saw that there was some wear and nicking on the old blades and the tips were worn down a bit. The leading edge of the new blades were about an eighth inch thick (not really sharp).

Using those new blades did not make a huge impact on the quality of the cut. If you cut the grass tall it will tend to knock the grass down instead of cutting it off.

Over summers and winter I will trim limbs down and then drive the shredder over them to somewhat chip them and reduce their bulk. I have done that after one icy winter that produced a LOT of downed limbs and I also put the shredder as low as possible to clean up the limbs and also clean the grass up and reduce any debris to chips.

I then took the original blades and a grinder and sharpened them to a fairly sharp edge (not as sharp as a new lawn mower blade but maybe a dull mowers blade).

I then purchased new bolts and nuts for the blades and installed the sharper blades. The grass and wildflowers were tall and thick. I mowed part of the property tall and it seemed to cut much better instead of knocking it down. There was less clumping and windrows of the grass. I then set it as low as possible without dragging and mowed a little of the property. It was able to cut and mulch the grass also.

In short the sharper blades gave a better cut quality of the grass in both tall cuts and shorter cuts. There was less grass cuttings that are visible on the grass.

I would NOT use blades sharpened like this if I was still trying to cut saplings or downed limbs. I think that the cut saplings could be sharp and damage your tires. I don’t think they would last long if they were cutting saplings and downed limbs. I also don’t think they would be able to reduce the debris well enough.

So sharpen them to be similar to a new shredder blade if you are using it like a shredder. But if you are cutting only grass and weeds I would recommend sharpening them closer to a dull lawn mower blade (I think they are too thick to get as sharp as a new lawn mower blade).

I recommend getting new bolts and hardware to make sure they are not worn out (but the old ones on mine were fine)

 

[The Evil Twin]

Brush blades cut by velocity. Not a honed edge. Watch some metube videos and heed the advice of the Hokie.

 

[James D]

Thanks to all of you. It's clear to me that you guys know a lot more than I do. "Based on your comments, I think that what I should do is to get a new set of blades to use for cutting mostly grass and really light stuff. I can then sharpen the old ones, not real sharp, just enough to reduce the load on the engine a bit. I'll probably replace the bolts too.
Thanks for your help, I really appreciate you guys taking the time to help me out.

 

[chim]

Thinking about balancing the blades. First impression is that if the blades weigh the same, the mower will automatically be balanced. But would it? What if two blades weighed exactly the same, but the weight wasn't distributed the same? For example the sharp end of one blade being heavier than the sharp end of its mate although the total weight of each blade matches.

 

[Russell King]

Thinking about balancing the blades. First impression is that if the blades weigh the same, the mower will automatically be balanced. But would it? What if two blades weighed exactly the same, but the weight wasn't distributed the same? For example the sharp end of one blade being heavier than the sharp end of its mate although the total weight of each blade matches.

The weight distribution of the blades will make a difference in the balance of the mower.
Making them the same weight is better than leaving them different weights but does not eliminate the unbalanced condition.

If you have a perfectly balanced rotating disk (think stump jumper) and put one heavy bolt in and one lighter bolt in the opposite side (both at the same radius) it would be unbalanced. If you moved the lighter bolt away from the center point you could get it to balance the heavy bolt (staying at same point).

The weight and distance from center point is creating the forces that create the unbalanced (or balanced) condition.

 

[Botamon]

Something to keep in mind if you are mowing mostly grass is the shape of the blades. At least on my 6' rotary mower the blades look like the blades on a lawn mower - that is, they have an upward bend at the rear edge of the blade that, when the blades are spinning, creates a lifting action (upward suction) that picks up the grass that was pushed down by the front of the mower and the tractor tires. That lifting action makes for a much nicer, closer cut. The old blades on my mower were so worn that they no longer provided any "lifting" action; there was a noticeable difference in the quality of the cut once I installed new blades.

 

[mikester]

I have a Woods 42 inch brush hog That I use with my Kubota B1750. The blades are so worn down that the front edge and the back look nearly the same. The dealer said that I would do better to replace them than to sharpen them. He gets $115 for the pair. The mower was well used when I got it, so I don't know how much mowing it took to wear them this much. I cut mostly grass with lots of brush, vines, small limbs and other junk mixed in. I never owned this kind of mower before so I don't know what is best. What would you experienced guys do?
Thanks.

Listen to the dealer.

If you don't like what he says sell everything and buy a condo in town.

 

[Motion]

I'd consider purchasing new blades and fasteners and wait until the off season to change them, at that time I'd also remove the stump jumper and reinstall using anti- seize, so when the time comes to change the output shaft seal, the job will be easier. Also, if it's a used piece of equipment either you have a shear pin or a slip clutch, if a pin, I'd install a new one to ensure its correct, if a slip clutch ensure its adjusted correctly. Check your driveline components.

 

[GeoHorn]

Check out two videos on this link: How to Sharpen Brush Cutter Blades… and… When to replace brush cutter blades.

Tractor Attachments Videos-Educational and Entertaining - Ask Tractor Mike

Tractor attachments videos from Ask Tractor Mike offer educational and entertaining information all about tractor implements and their uses.

asktractormike.com

 

[ChiefWebb]

My father in law always had his brush cutter blades sharpened by his local blacksmith shop. They would reshape them back to new looking without removing any metal. He had three pair and would take in two pair for sharpening at a time. I was amazed at the quality of the blacksmith's work. He told me the cost of having them sharpened was very reasonable. The blades lasted and were never replaced, until the deck on his cutter finally rusted away and he replaced it.

 

[James D]

Check out two videos on this link: How to Sharpen Brush Cutter Blades… and… When to replace brush cutter blades.

Tractor Attachments Videos-Educational and Entertaining - Ask Tractor Mike

Tractor attachments videos from Ask Tractor Mike offer educational and entertaining information all about tractor implements and their uses.

asktractormike.com

Check out two videos on this link: How to Sharpen Brush Cutter Blades… and… When to replace brush cutter blades.

Tractor Attachments Videos-Educational and Entertaining - Ask Tractor Mike

Tractor attachments videos from Ask Tractor Mike offer educational and entertaining information all about tractor implements and their uses.

asktractormike.com

 

[GeoHorn]

My father in law always had his brush cutter blades sharpened by his local blacksmith shop. They would reshape them back to new looking without removing any metal. He had three pair and would take in two pair for sharpening at a time. I was amazed at the quality of the blacksmith's work. He told me the cost of having them sharpened was very reasonable. The blades lasted and were never replaced, until the deck on his cutter finally rusted away and he replaced it.

Yep. Old-School guys would prefer a blacksmith to heat, hammer back to condition, and re-temper their blades instead of grinding-way old material which eventually and materially reduces the blade construction. (Grinding the edges to sharpen them also removes the temper…the new edge becoming soft and more quickly worn and damaged.)

The actual edge shape should not cut the skin if you run your hand down the edge. A Fresh/New blade actually has a FLAT leading edge…for strength…and to “break” the stem of plants. Specific instructions on blade maintenance from Rhino describe the leading edge to have a 1/16” flat leading edge.

But the videos I posted …for those who didn’t view them…. points out that a rotary cutter is Not a Finish Mower…. it is intended to ”shred“ small woody brush and weeds.…and the condition of the blades “sharp” edge is almost unimportant…. dull blades whack the brush just as effectively as “sharp” edges do on that type implement.