Buying used flail mower (JD or Ford)

def38 · Jul 14, 2020

Well, you hit the flail mower lottery. Nice going. Your tractor will handle even denser growth and grass. Wait until you get into brush and sticks...you'll be amazed at how those mowers mulch up most anything in their path...even Buick hubcaps. As for the oil, I would add some Rislone to the gearcase and run it for several hours to clean up any sludge. Then drain the oil and refill with 75W-140 GL-5 synthetic gear oil. Then forget about the gearcase lube for years. I use this oil in all my gearcases and have never had a failure. As for the knives, I would run them for a while then maybe remove them at the end of the season for sharpening. You'll be further amazed at how a new sharp edge on flails can help. Finally, are you going to clean that JD up and make it presentable? If so, more photos requested. Nice work.

Now, what are you going to do with the rotary cutter you also bought? Maybe that's another thread?

pripyat · Jul 15, 2020

The guy I bought it from has a full-time job at a pharmaceutical plant but does "junk" as a hobby. He's got over 150 vehicles in his yard, he is waiting for steel prices to go up. He is playing the steel price stock market? He had a massive batwing, 4 different brush hogs, a couple finish mowers, a couple tractor/loaders. Funny, it is obvious from the road that he has a junk yard but has signs all down the driveway, "KEEP OUT", "NOTHING FOR SALE", "PRIVATE PROPERTY". I was praying I hadn't pulled into the wrong driveway. :laughing:

A lot of his stuff had lot tags on it from auctions. He said he knew that he could sell the mowers for more but didn't list them because he doesn't like dealing with the "Crackheads". I found this guy through a friend. Apparently he just sells to people he knows or friends of friends.

Would my dad's 1526 pull the smaller Ford flail? Dad does a lot of lot cleanup for friends, if his tractor with loaded tires can wield the smaller Ford, I believe we are going to go pick it up as well. Dad was equally impressed with the work done by my new JD. Plus, if he gets the Ford, he will have gotten something out of letting me borrow his truck/trailer and the dent I put in his trailer fender.

As for the rotary cutter, honestly, if the flail can't cut it, I'll just use the chainsaw. I'm going to finish my 20 acres before I consider getting rid of it just to be sure. I do want to get a wheel on it and play with it a little. I confirmed this morning that the diameter of the shaft for the wheel mount does not match my older broken rotary cutter. Looks to be 1-7/8 or 2", I didn't have my caliper with me.

What blades would be best in the future for replacing these? I may start keeping an eye on ebay for auction-style listings for new blades. They are pricey! I'll be sure to inspect the blades CLOSELY next time I purchase a flail.

[edit] For clarity, the blades would be for future. I agree that they have a good bit of life left in them. If they continue to cut the way they do now, I don't even see a need to sharpen them.

pripyat · Jul 15, 2020

One last thing - What would I need to do or buy to get the clutch for the bush hog back to operational? Or is this supposed to be a shear plate?

Skagit · Jul 15, 2020

pripyat said:
One last thing - What would I need to do or buy to get the clutch for the bush hog back to operational? Or is this supposed to be a shear plate?

View attachment 663350

That's a shear bolt, you're good to go.

TheFarmerInAdell · Jul 15, 2020

Those knives are reversible. When one side gets dull, just flip them over. And you can sharpen them if you don't wear them out too much. The ones that were on my Alamo that came from the Illinois Tollway had a nice radius at the corner. Those were beyond sharpening. You have some very heavy duty knives on there. Just be sure you don't overheat them when sharpening them. They shouldn't be too hot to touch when sharpening otherwise you risk changing the temper if they have been heat treated.

Here is a clip from the Flailmaster catalog for your mower.

It appears you have the heavy duty version. I think the only difference is the knives. You can likely switch to the smooth cut knives if you'd like. Flailmaster is still fielding phone calls and selling parts, but from what I understand they're not making any right now. Give them a call to see if they have parts for your unit left.

pripyat · Jul 16, 2020

Here is what the blades look like. Should I consider flipping them, sharpening them, or leaving them?

TheFarmerInAdell · Jul 16, 2020

pripyat said:
Here is what the blades look like. Should I consider flipping them, sharpening them, or leaving them?

View attachment 663470

View attachment 663469

View attachment 663468

I would sharpen the non-radius edge and make sure that edge is the one cutting the grass. I'm not sure which way your rotor spins, but I'm guessing the edge with the radius is the edge currently doing the cutting. The blades don't need to be razor sharp, just not beat up and dull.

leonz · Jul 16, 2020

Invest in a slow speed wet grinder to sharpen your side slicer knives and you will not lose your cutting edge from heat damage.
you can purchase the wet grinders from micro mark and the angle setters from the mastercraft folks.

Industrial Toys · Jul 16, 2020

I started to sharpen the (regular) knives on my old Ford 917. For off lawn cutting and with the many stones around here, I just gave up on that. Then, mostly just made sure to replace missing and damaged knives.

Hay Dude · Jul 16, 2020

JD390s are very well built and usually a lot more expensive than what you paid
Mine was $2200.
Excellent mowers.

pripyat · Jul 16, 2020

I ran the mower a bit and then sucked the oil out the gearbox. It look pretty bad. I put some cheap gear oil back in it since I'm going to swap it again in another couple hours.

I'm noticing that there are no grease fittings for the rotor that has the cutters attached. Is there any reason to lubricate this or is this even possible?

Industrial Toys · Jul 16, 2020

There certainly should be. I can't see it being a sealed bearing. Did the zerks get broken off?

pripyat · Jul 17, 2020

I don't see anything and it isn't mentioned here:
OMP70756

kthompson · Jul 17, 2020

The one thing I was going to recommend for you was be sure you keep cutter rotor grease well for those rotors are turning some very high rpms. Think about the tip speed needed for good cutting. Now on a rough cut single spindle mower their spindle has the blade tip out there say two feet. The flail mower has it blade tip out there say...8 inches? The flail mower rotor is really got to turn much higher rpms and if there is no grease fittings for it would surprise me greatly. Look very carefully for on the flail mowers I have had and have now the grease fitting is often protected or maybe hidden by braces and even rubber plugs to protect them. You need to be sure you are using grease recommended for again a flail mower rotor is flying compared to a rotary mower. This is also reason you need to replace worn flails all at one time.

Congratulations on the mower, for brush cutting I think a rotary mower will cut faster but a flail mower will mulch it where the rotary mower will not and if you are not aware a flail mower will not throw objects like a rotary mower will, much safer. One reason they are used for road cutting in some areas. Flail mower is not as likely to leave sharp stubble either as a rotary mower. The one area where a flail is not a good is using on a lawn and making tight turns if rear roller is on the ground.

Industrial Toys · Jul 17, 2020

Rather then just looking for zerks on a machine, it's easier if you know how the machine works and then will often know where there should be zerks. Sometimes idlers have sealed bearings but usually the bearings doing the work will have zerks.

def38 · Jul 17, 2020

BTW, the flail rotor is not a high speed application. Most turn at about 5X PTO RPM. Typical bearing sizes used in the rotor are rated at 10,000RPM. Also load specs are more than adequate for this application. But, they do need grease from time to time. Don't over grease or you may force out the bearing shields if so equipped. Use a Lithium soaped grease of NLGI II grade. Avoid Calcium soaped greases inasmuch as they will wash out more easily when in contact with water. Marine grease while more costly is a good choice.

CADplans · Jul 17, 2020

def38 said:
BTW, the flail rotor is not a high speed application.
But, they do need grease from time to time.

I have owned my 390 since it was new sitting on the dealers lot,,
There never has been a grease fitting on the rotor bearings,,

There is a grease fitting on the roller bearings,, I think that has grease fittings, because bearings HATE to turn super slow,,

You can see the roller bearing grease fitting in this pic,,

Hay Dude · Jul 17, 2020

Mine is in the yellow circle

Industrial Toys · Jul 17, 2020

Nice tractor/mower combo.

I think that a poor choice of Deere not to put greasable bearings on the Rotor.

pripyat · Jul 17, 2020

I just did some digging, it is true that the rotor bearings are not greasable.

The bearing is part number JD9275 which cross references to TIMKEN 1106KRRB5. Cross Reference Chart

Here is a PDF on the design of the bearings. It is recommended to not grease them.

https://www.paramountindustrialproducts.com/pdf/1/101.pdf

In other news I mentioned previously that I suctioned the old gearbox oil out and replaced it with new. It was pretty nasty.