Brush Hog Blades........Wondering??????

[Caryc]

This is something I have been wondering about. Do any of you balance the blades on your brush hog? What I mean is when you remove the blades for sharpening, do you also attempt to get them at the same weight so they will be balanced on the shaft?

I have Woods M5 brush hog and it has the access hole in the top of the deck to remove the blades from the top side. It's very easy to remove them for sharpening which I do on a grinding wheel and a 1" belt sander. Seems that it would be easy to get them both the same weight by grinding some off the edge of the heavy one.

I've never actually weighed them to see how close they are. I'm usually in a hurry when I sharpen them since I've put off my brush hogging for too long.

But, it seems to me that it would be better for the gear box if the blades both weighed the same. I know from reading instructions that you shouldn't put a knife edge on the blades. You use more of a blunt edge when you sharpen them.

I have a digital postal scale so I'll weigh them the next time I have them out.

 

[souNdguy]

if they look close and matched in length, width, and wear pattern.. I run em.

I won't run 1 new with one worn..e tc..

 

[Anonymous-0]

I do not take mine off. Block it up about 12-16" off grind and grind them on the mower,

 

[Caryc]

(quoted from post at 18:17:50 05/26/12) I do not take mine off. Block it up about 12-16" off grind and grind them on the mower,

Well, that's fine if you have a mower where they can't be removed from the top. I don't know why they aren't all built like mine. It's so much easier to just remove the blades from the top with just one bolt on each one.

 

[Ultradog MN]

That is a thought I've had more than once myself.
Weigh the blades and see how far off they are. I don't know the weight of an average rotary blade but what would you guess - 10 lbs apiece?
Probably within 4 ounces of each other would be nice. Also I've thought about the balance of the stump jumper. Maybe put a straight edge across the underside of the mower and measure from it to the stump jumper as you turn it by hand. Hopefully it would be within 1/8" to 1/4" of being true?
They do balance engines for a reason - makes them perform better, last longer and produce more horsepower. I can't see why the same wouldn't be true with a heavy mower - perform better, use less HP and last longer.

 

[souNdguy]

at some point you have sooo much rotating mass that even a bit of difference on the variable pieces.. the blades.. means less to the whole.

at work we have industrial milling and mixing machines that gring up roadbed. the teeth are tines and about 1' long.. there are 4 spindle wheels on each side of the machine.. 8 total each wheel holds 8 teeth. the teeth have about 6" that can / will wear off. ie.. 6" goes into a retainer poctet and is retained with a nail thru the square pocket that holds in a cutout nub on the tine. ina given job of milling.. we will throw teeth.. break teeth off... break pockets off.. and wear teeth normally. tooth is 5/8 to 1/2" material depending on manufaturer.. pocket holds eaither.. pocket itself must weigh 8#.. teeth, as much.. maybee 7 dunno...

at the end of the day.. you can have DOZENS of pounds of weight difference from one side of the axle to the other...

the operator never knows or feels it till the end of the day when they look under there...

axle is 8" diameter.. and the rear end that drives it looks about the same size as on our western star semi tractor... engine is either a cummins 290 or 300.

when you look at the rotational mass of the engine and driveline and that huge blade carrier.. the gears in the gearbox, etc... a few ounces out a thte end of the blade are heading towards minutia..

obviously the smaller the mower and whatnot, the more difference it makes... as that small part is a larger part of the whole..

a 15hp tractor with a 3' mower missing 3" of balde on one side, vs a 70hp machine with a 10' mower missing 3" of balde on one soide of one side.. well.. I suspect the 15hp tractor driver MAY LIKELY notice the difference. I do not suspect the 70hp driver will.. er.. at least I didn't when i broke a blade on my 10' mower.. nothing shook.. but I did notice striping on my next pass.. , as the blades were a bit worn anyway..

 

[Ultradog MN]

I broke a blade clean off a few years ago and boy oh boy did it shake then.
I don't know if the old blade was having problems prior to breaking but it did run noticeably smoother after I put the new ones on.

 

[carlntexas]

(quoted from post at 20:17:50 05/26/12) I do not take mine off. Block it up about 12-16" off grind and grind them on the mower,

hat's what I do on mine because I can't get them off.

 

[souNdguy]

i can see where an entire blade coming off would make a significant difference.

right across the hole.. that's the place that worries me the most..

 

[ericlb]

ive never actually weighed any of mine, but what ive always done is pay attention to the grinding, and do about the same amount on each of the blades, i should mention ive brush hogged for over 30 years and i figure ive done this enough to be reasonably accurate lol, new blades should be reasonably the same and since both wear the same barring any impacts, they will stay about the same after several brush hog wrecks in fields where " there is nothing in them" [except old 2 3/8ths pipe stumps] i only do fields i know personaly now for brush or sapplings, nothing beats a friend who has a skid steer with a masticater attachment lol, and he chews the stuff to within a inch or 2 of the ground for me

 

[Mad Farmer]

It's not only the total mass, but the distribution of the mass.
Heavier at the end will contribute more than heavy at the bolt.

Now we can start a NASCAR MOWER THREAD.......

 

[Jimj_WA]

I need to do some mowing today and was going to sharpen the blades without taking them off like i usually do. after seeing Ultradogs broken blade pict i think i'll take 'em off and look for cracks around the bolt holes and weigh 'em too.
........Jim

 

[Caryc]

(quoted from post at 08:02:00 05/27/12) I need to do some mowing today and was going to sharpen the blades without taking them off like i usually do. after seeing Ultradogs broken blade pict i think i'll take 'em off and look for cracks around the bolt holes and weigh 'em too.
........Jim

Please let us know what they weigh.

 

[LeoinMI]

Used to mow the Airport property I work for with 20 foot batwing mowers. You could tell if your blades were out of balance with the vibration of the pto shaft,..especially after you hit someting like a big rock. We used to weigh the blades when we removed them for sharpening and discarded anyones with big pieces missing or bent beyound fixing. The batwings had shims that acted like counterweights that went under the pin and bolt that held the blade to the mower deck and they usually balanced out for the most part.

 

[Dean]

I have never balanced lawn mower blades, much less "bush hog" blades.

Nor do I remove them for sharpening, which I do very frequently. Just raise the mower and reach under with a 4 1'2" angle grinder. Takes about ten minutes.

Dean

 

[Ken(Ark)]

.......what ive always done is pay attention to the grinding, and do about the same amount on each of the blades ......

Ditto

 

[W_B]

That's what I do, block it up and use the angle grinder to sharpen them up. I doubt I could get them off without a major struggle anyway.

 

[dbNga]

I lost 4-5 inches off the tip of one of the blade on my 4 foot bush hog and talk about dancin'...

 

[Kenster]

(quoted from post at 19:44:11 05/27/12) I have never balanced lawn mower blades, much less "bush hog" blades.

Nor do I remove them for sharpening, which I do very frequently. Just raise the mower and reach under with a 4 1'2" angle grinder. Takes about ten minutes.

Dean

That's what I do, too, but I chain the mower up and set big wooden blocks under it. I wouldn't trust even the best hydraulics while I'm under there.

 

[Caryc]

I'm guessing that you guys that say you just crawl under your brush hog to sharpen the blades do so because you can't remove them from the top.

I can't imagine anyone crawling under one of those things if you could access the blades from the top. As I said on another post I don't see why they are not all made to access the blades from the top.

 

[R Geiger]

(quoted from post at 00:59:50 06/18/12) I'm guessing that you guys that say you just crawl under your brush hog to sharpen the blades do so because you can't remove them from the top.

I can't imagine anyone crawling under one of those things if you could access the blades from the top. As I said on another post I don't see why they are not all made to access the blades from the top.

I use a come a long to raise the deck vertical. I remove the drive shaft and the top link and raise the deck into a verticle position and then chain and block as necessary to keep it there, then I can stand and sharpen the blades. I can not get them off from the top or bottom. getting old and weak i recon!

 

[Caryc]

(quoted from post at 09:44:18 06/17/12)

(quoted from post at 00:59:50 06/18/12) I'm guessing that you guys that say you just crawl under your brush hog to sharpen the blades do so because you can't remove them from the top.

I can't imagine anyone crawling under one of those things if you could access the blades from the top. As I said on another post I don't see why they are not all made to access the blades from the top.

I use a come a long to raise the deck vertical. I remove the drive shaft and the top link and raise the deck into a verticle position and then chain and block as necessary to keep it there, then I can stand and sharpen the blades. I can not get them off from the top or bottom. getting old and weak i recon!

I imagine that a lot of those access from the bottom only blades have the fasteners pretty well rusted in place. I can imagine that some of you guys have come up with some crafty ways to get at them also.

 

[Hobo,NC]

By the time folks bring in their hog for blade sharping they are worn out,,, new blades are $22 @ piece much less than I charge to fudge with a old blade...

I have been lucky most stump jumpers I have ran into fell right off,,, the hub was worn out and needed rebuilding... The pins that hold the blades were also worn out and needed to be cut off :twisted:

I remove the blades just to make sure the slot that holds the pin is not worn out and to keep the big arse nut fee enuff to come off,,, is it a over kill YES but if you have ever had to remove a stuck stump jumper to me worth the extra time...

 

[NoNewParts]

I remove the blades just to make sure the slot that holds the pin is not worn out and to keep the big arse nut fee enuff to come off,,, is it a over kill YES but if you have ever had to remove a stuck stump jumper to me worth the extra time...

wish everybody got them free once in awhile.
owner wanted me and another hand to try and save an ancient
offset orchard mower with 2 sets of blades
junk, after cobbing up the shafts and lift cylinder,
we went underneath and HOURS later got the blades freed/fixed up.
lots of work and if it wouldn't have been good old steel stuff,
we would have failed. Everything eventually came apart.

for the poster, the blades were in bad shape and obviously not
weight balanced, and it did vibrate some. But it got the orchards mowed that season.