Flail Mower Flail Hammer Sharpening...

[bjcsc]

Tomorrow I begin running through a used Bomford B457 flail mower that I just bought. The flail hammers all look to be in good shape, but I am not sure how sharp they should be, or how much of their original length should be there (when is too worn?). I would assume sharpened similarly to my bushhog blade, but don't know for sure. I also don't know if I should check them (or the pattern of how to check them) for weight regarding the rotor shaft being balanced. Any advise from the flail users? The flails are the type pictured below (#1) and about as sharp.

Lastly, this is a twin pump unit. I am considering re-plumbing the hydraulics so I can control the three cylinder from my 3 rear SCVs instead of using the cable setup/valve. Bad idea?

 

[MtnViewRanch]

This is just my opinion, but I would not take the time to sharpen the cutters. A fresh edge is sharp, but it doesn't stay that way for long. Unless you plan on sharpening them each time that you use it, it's just a waste of time. If you are using it to mow lawns, then you have the wrong style of cutters. I have the same style of cutters that you have shown, and I just run mine.

Just my opinion and it is not worth all that much.
Good luck

 

[bjcsc]

I pretty much feel the same way. I won't be mowing lawns, I'll be cutting ditches, ponds, the sides of my 1/2milelong ever encroaching driveway, etc...

Do you balance yours? or check it?

 

[sandman2234]

I just happen to have one sitting on my desk that is new so I shot a quick picture of it. It appears to be about a 40 degree angle but I would have guessed 35 if I hadn't of measured it. Mine came with some pretty worn out blades, but after pricing them, I decided to give the old ones a sharpen to see how they would do. They were pretty dull, with a rounded 1/4" flat face doing the cutting instead of a knife bladed edge. It would still cut trees, so that must be atributed to the weight and speed of the cutters, more than the cutting edge. The new set that came with my mower, although incomplete, is a lot of money and I would seriously run those for as long as possible. I turned my mower on it's end, and sharpened each blade with a 4.5" right angle grinder. I learned on the first one that if the grinder slips, it will remove a good portion of thumbnail and flesh before stopping. Nothing serious, but it did hurt like it was. I decided that holding each blade with a pair of vice grips would be a better idea, and suggest that highly. Also a good full face shield to prevent flying debris from entering your eyes. Although a lot of trouble sitting on a stool while working, it is probably hands down better than trying to remove them and reinstalling them. Most of the bolts and nuts will be damaged during removal, so sharpening on the machine will probably work out better.
David from jax
http://img.photobucket.com/albums/v177/sandman2234/tractors/Turnerflailblade.jpg

 

[J_J]

Tomorrow I begin running through a used Bomford B457 flail mower that I just bought. The flail hammers all look to be in good shape, but I am not sure how sharp they should be, or how much of their original length should be there (when is too worn?). I would assume sharpened similarly to my bushhog blade, but don't know for sure. I also don't know if I should check them (or the pattern of how to check them) for weight regarding the rotor shaft being balanced. Any advise from the flail users? The flails are the type pictured below (#1) and about as sharp.

Lastly, this is a twin pump unit. I am considering re-plumbing the hydraulics so I can control the three cylinder from my 3 rear SCVs instead of using the cable setup/valve. Bad idea?

Your picture is showing two different type blades. The hammer type is used for rough cutting. The twin blades are used for finish cutting. Some of the blades are designed to be reversed for a new cutting edge. It would be very hard to balance your drum roller with all the blades attached. You are slinging around a lot metal. If you experience a lot of vibration, look for a missing hammer cutter. The twin finish cutters are cheaper. If you do a lot of grinding on those hammer cutters, you could really unbalance the whole thing.

 

[sandman2234]

I didn't do any sort of balancing on mine, except trying to grind somewhere near the same angle and amount on each one. No problems noted.
If you decide to replace the cutters on yours, send me the old ones as I have figured out they are worth somewhere between gold and platinum.
David from jax

 

[atgreene]

I never have sharpened mine on my Kuhn Flail mower. Blades are an expendable item, I'm in business to make money and if I spend more time to sharpen something than I can buy it for, I'm falling behind.

BTW, there is another type blade. When I bought my mower it had the double knife style but with no shackle to connect to the drum. It bolted direct and was longer. The style that bolts direct do not do well around rocks at all.

 

[bjcsc]

Thanks for the pic David. I'm with you on the grinder (BTDT with the finger, too. Best part is it doesn't bleed, but sure hurts the next day). If I decide to sharpen them, I would definitely do it in place. I can raise it completely vertical and to whatever height (up to 15') once I go through the hydraulics. I'll get some pics of the hammers and post them here tomorrow so you guys can see what I see...

 

[MtnViewRanch]

I pretty much feel the same way. I won't be mowing lawns, I'll be cutting ditches, ponds, the sides of my 1/2milelong ever encroaching driveway, etc...

Do you balance yours? or check it?

I have done nothing to mine but use it, grease it and wash it off. So far so good.

 

[tallyho8]

The hammer you show as #1 in your photo is for rough cutting and probably should never be sharpened. The blades in #9 are for smooth cutting and when one side gets dull and worn down you just turn it around and use the other side. By the time I wear both sides down there is usually nothing left to sharpen.

 

[bjcsc]

Here are a couple of pictures of the hammers. They seem to be edged the opposite of the one in David's pic, i.e. the bevel is on the bottom vs. the top. Based on what you guys have said so far, and my limited knowledge, they seem to be OK as is. Any discord?

 

[sandman2234]

That apparent edge that looks like it is opposite mine is from wear. As they go round and round, the bottom edge is hitting more stuff, and it wears faster. The one I took the picture of is a brand new one, straight from Bomford. I agree that sharpening them is a job, but depending on what you are doing, if it makes a difference or not. I know mine was beating stuff into pulp rather than cutting it, which may or may not be ok depending on what your doing. I went ahead and sharpened them, because I didn't like the way it was shredding limbs along the paths I was trying to trim. It may have something to do with the difference in how flail mowers are used. Most are 3 point mounts and mow either behind or alongside the path of a tractor. Mine is unique in that it mows anywhere behind or beside the tractor, but also up to twenty five feet above it, since it is mounted on a boom mower. I took the bare minimum amount off the blades when sharpening them. Bomford showed me something when they sharpened their blades at 40 degrees rather than the typical 35 degree angle used with a lot of cutting devices. It showed that a more blount cut would still do the job, while allowing for a longer wear factor. It is obvious to me that your blades are a long way from where mine were when I received it, so you can run it for quite a while before sharpening them. As I stated before, the flat edge that should have been the point of the sharpened end was about a quarter of an inch, whereas yours appear to be about half of that amount. With the price of the blades being what they are, if they are cutting a satisfactory appearing cut, I would leave them alone for now and wait till the blunt edge gets a little wider. That is just my thoughts, and based on my flail mower experience which is limited in longevity. Part of that is also based on my limited personal use, and not as a commercial end user. I don't have a paying use for my mower and expenses are covered by my regular income. The company I purchased the tractor and boom mower from did not sharpen the blades either, they simply replaced them when they became worn. They are a fortune five hundred company and paying someone to sharpen them, versus ordering new blades is not the way they do business. They throw away more blades than I will ever use.
David from jax

 

[sandman2234]

I just noticed your signature contained the fact that yours is also a boom mower, so that answers the question about what your doing with it. It probably isn't doing open fields like my JD flail mower does, or even the shoulder of the road, as a finish mower would do that quicker. It is probably made to handle pretty much anything that grows in ditches and roadsides, and rated up to 1.5" in diameter. I know if you want to remove a tree that is in the way, and it is 4" in diameter, starting at the top and taking it out is probably what happens. I love the way mine pretty much takes out anything in it's path that I want removed. Dead trees are also removed safer than any other way I know of, because you don't have to get too close to them in order to push them over. (thinking dead pine trees here)
I am not quite sure what you have in mind about the hydraulic question, could you elaborate it a little in terms of what you have in mind and why?
I noticed that all the mowers on Bomford-Turners website show the mower extended to the max or close and only on single rear wheel tractors. My Ford 7710 4fwa tractor is massive, and yet I can easily raise the front wheels off the ground by extending the boom rearward. This tells me that sideways is also a problem with weight which is why the previous operator told me not to consider removing the dual rear wheels. Your tractor is smaller than mine, by about half the weight but your mower appears to be about 10 feet shorter in reach so that would help with the weight problem that mine tends to exhibit.
David from jax

 

[Grrrr]

I would also say there is a lot of life left in those blades yet if you are only going to be doing rough cutting. They will chomp through anything you can place them on.

We use them on hedges ( they are known as hedgecutters in the UK) and once you get used to operating them you can leave a really nice finish with very little debris as they mulch it up so small and tend to blow it back in to the ground.

 

[J_J]

David, Is your boom mower designed to cut up from the bottom? Is there any good logic for cutting up vice cutting down? It seems like cutting down would be taking little bites as you move forward, and if you cut up, you would be cutting the whole stalk, and slinging the stalk around the shaft. Do you ever wind up vines and tall weeds on the shaft?

When I bought the hydraulic flail mower, it was used, and someone had converted all the blades to slicer blades. They look like edger blades cut just behind the mounting hole. I am guessing that they used this arrangement to dethatch sod. I bought all new finish blades, hangers and bolts. and installed them. While installing them, I found a lot of broken or worn bolts and hangers .

 

[sandman2234]

Now this will be interesting to discribe...
My mower will mower either side of the tractor, but the deck is supposed to turn around on the end to do that. The switch at the end of one of the controls that makes it rotate isn't working so if I cut on the opposite side (passenger side) the roller is in the front and the blades are turning the wrong way. It still cuts fine, but it is supposed to cut in a manner to where it throws the stuff back in front of it, or cut as it goes forward and up. It is supposed to cut like my JD fail mower, which if you stand on the left side (drivers side) the blades are turning clockwise. (make sense?) This puts the roller at the rear, as a height guage and allows the open area to bring in the material to be cut.
As far as I can tell, the only reason to cut from the bottom up, versus the other, is the way it cuts the stalk. Coming at it from the top down, your going to be cutting down through the stalk whereas from the bottom up, it will just cut across the stalk and by the time the blade starts upward, the stalk is already cut and it just throws it out of the way.This is due to the forward motion of the tractor as the blades come around. I haven't ever wrapped any vines or things up with it, except for barbwire fence. Found some of that but luckily I was quick on the clutch, disengaging the pto. I got plenty of warning, as the blades like to make a lot of noise when disturbed out of their normal rotation. I just raised the boom, backed a tire on the stuff laying on the barbwire and slowly extended the boom with it turned off. It just unrolled the wire right off the center shaft. Talk about lucky!
Hopefully this makes sense.
David from jax

 

[bjcsc]

OK. So I'm good on the hammers for my intended use. Thanks everyone.

I am not quite sure what you have in mind about the hydraulic question, could you elaborate it a little in terms of what you have in mind and why?

These mowers come one of two ways: Single Pump and Twin Pump. Mine is a twin pump. One pump drives the rotor shaft and the other supplies a valve body and eventually the three boom cylinders. That valve body has cables that operate the spools. 6' away, at the end of the bundle of cables, are the controls. They are designed to be bolted to something (fender, post, whatever). I do not want to mount these controls to my tractor. It would be easier for me, esp. with three rear SCVs (remotes), to re-plumb, lose the cable valve, and run the cylinders off of my tractor's hydraulics. The rotor would still be running off of the mower's pump/hydraulics.

I am a bit concerned about the weight, too. The reservoir is offset to the left, but I will be interested to see how stable it is. I intend to explore this very carefully! There are places I could bolt to, so I could fab up some brackets for some counterweight if need be. We'll see...

I was cleaning it up today, straightening out the bent feet, learning the parts, degreasing, etc., and i found another interesting thing. The mower hooks to the three point, but the lower links have an extra bracket. A piece of chain goes from the bracket, to a fitting in an alternate hole on the tractor toplink bracket and to the other lower link. The instructions say to raise it up, attach the chains equally, and lower it until the chains are tight. (see below) Essentially, this takes the load off of the lower arms and transfers it to the toplink bracket on the tractor. Is this how most of them attach? What is the theory?

 

[sandman2234]

I can't help you with the mounting questions, because mine doesn't mount to the 3pt hitch. That actually is one of my problems. Since it didn't mount to the 3pt hitch, the arms were just in the way, so they were removed and discarded. Now in order to remove the boom mower and replace it with a 3pt implement, I have to locate a set of lower lift arms, plus the adjusters that go up to the short arms which actually raise them. I could just order a set used for $750, but until I become gainfully employed, I really need to pass on them for now. My tank is centered and has two arms that come out from under it that mount to the bottom of each axle, in case you are wondering how mine mounts. It does have a 3 pt top link hookup which is the third point.
Mine must be the one pump version. One pump engages and activates the blades in the cutting head. The cylinders for the side to side, up/down, boom up/ down, boom extend/retract etc are all run off the tractor's hydraulic system. It also has the controls that are the way you describe them mounted on a bracket that is bolted to the ROPS. I also have a piece of Lexan bolted to that side since it is the side that most cutting is done from. It keeps the mower from throwing things into your face as your watching it work. That Lexan also stabilizes the arm that the levers are mounted to to keep them from becoming a problem.
I understand not wanting to permenantly mount the controls on your tractor, especially if you use it for several other uses. Mine came with the boom mower and was a dedicated machine to the previous owner. I only bought the tractor because of it's FWA (4x4) because I was getting tired of getting stuck. The boom mower was just an additional bonus.
I think a bolt on bracket from your ROPS to handle your valve controls might be easier than changing out the hydraulic input, but that is just me thinking. It should be able to be done without drilling any holes if you think about it carefully.
David from jax

 

[Grrrr]

I also think you would be better keeping the controls separate.

I think you will get much faster reaction times the way it is now and I don't know if your tractor would have enough oil to fill all the cylinders on the boom and still have any in the tank.

I also think it might turn into a bit of a spaghetti junction on your tractors backend with all those different connections and attatchments. I would keep it simple