Rebirth of a 6 Foot Flail Mower

[awemawson]

I've been looking for a slightly wider flail mower for grass cutting for quite some time - the current one that I use (A Buchner) is a 5 foot cut and was was originally 'front mounted' on a Buchner four wheel drive 'bank mower'. I converted it to mount on a tractor 'three point linkage' years back. It works very well and will gobble up almost anything you drive it over, but as it was originally intended to go on the front of a vehicle, the flail spins the wrong way and throws all the cuttings over your back as you use it 

Now new ones are an astronomical price, apart from some very cheap imports made from old bean cans and good for perhaps two seasons  So I've been keeping an eye on them on eBay. Well used but working examples have been fetching £1K5 and are usually miles away making transport expensive and difficult.

This one popped up only 50 miles away as 'spares or repairs', which as you probably are aware is more my sort of thing  Close examination of pictures and interogation of the seller revealed a very well made (and UK made) 'Turner Turbomower' that in recent years has been driven into the ground.

Stoutly constructed from 10 mm plate these things are in essence extremely simple. A PTO shaft from the tractor, spinning at 540 rpm drives a 90 degree gear box, that in turn, via belts, drives the flail shaft. On the shaft are the individual flail elements that swing on pivots to do the actual cutting. At the rear is a 6" diameter roller that runs on the ground setting the cutting height.

To the front are sturdy steel flaps that hang down on pivots to stop anything being thrown forwards, and a rubber skirt to the rear for the same purpose.

As declared by the seller the bearings are shot, both on the roller and the flail shaft. In addition the pto shaft is wonky, the roller has a big dent in it, and the steel flaps and their support bar are bent all over the place.

In all a bit of a basket case, but so long as the 90 degree gear box has survived all eminently re-buildable and mainly needing time rather than money. Talking of which, against stiff competition from 13 other bidders it was mine for £371 - a price I was very happy to pay.

So I set off early Saturday morning to collect it with the big 17 foot Ifor Williams trailer - journey was going spiffingly until some poor chap rolled his lorry a little in front of me and I ended up going down totally unexplored local narrow lanes through villages where the Normans were still pillaging, eventually emerging onto wider roads 2 hours later 

Never mind - she's now home, and will sit on the trailer until a bit of floor space is cleared up in the workshop - this will probably be a winter project so don't expect updates very soon.

First pictures from the eBay advert:

[awemawson]

And then some I've taken now it's back here:

[wgw]

Nice one, I did not realise they were so valuable. I used to design those things in an other life. Worth checking the gear box mounting to the main body , sometimes cracking starts , esp. at welds.

[Spurry]

Looks like an interesting project. It amazes me that some people could actually use a machine in that sort of condition.
Do you not find that the tractor wheels flatten the grass/weeds whatever, before the mower gets there?
My green machine can fit a flail at the front, and it worked well as it was wider than the wheel track. ( Hired one to try - some of the weeds were above cab height.)
The twin rotor one I normally use is hindered by being narrower than the wheels so those weeds do not get chopped down very well.
I now know I should have bought a triple rotor.
Pete

[awemawson]

It's being used to keep a field in fettle rather than break new ground  I have to say my current flail leaves a much better finish than your picture.

Generally I'll mow when I move the sheep off a field, as for some reason their appetite doesn't seem whetted by rushes and thistles and they leave them sticking out of the ground !

When the grass is growing rampantly I'll also cut it to about a 4" staple, as much longer than that they won't eat. 

Obviously yes you are running on the grass that you are about to mow, and unless you have a front mounted three point mount and pto drive you have little choice.

[awemawson]

Well amazingly eBay has provided the correct 'operators manual' for this flail - amazing because Turners were taken over by Bomfords many years ago and not a lot of documentation seems to have survived the sale. It's by no means essential as it's a pretty simple device, but nice to have if only as it gives exploded diagrams of the workings:

[awemawson]

So having lugged the Traub lathe out of the workshop I now have room to bring the flail in for a bit of titivation.

Grabbed it with the Forklift and it conveniently came to rest with the mangled flappy plates upwards and easy to get at for removal.

[awemawson]

But first I removed the PTO shaft before it got bent. Initial inspection suggests it's ok apart from needing a replacement safety cover, but it might be as cheap to buy a new entire unit - time will tell 

Then I set too removing the flaps. They pivot on a 1/2" shaft that runs through several suitably placed brackets on the body of the flail. It wasn't coming easily but eventually gave in to brute force - it was far from straight. But out it came depositing all the flaps on the floor 

[awemawson]

Now I can't get too involved today as I have to play 'mine host' to visitors in the cottages shortly, however I thought I'd try flattening one of the flappy plates under the Epco 60 ton press.

I had expected that although it would flatten, there'd be a fair amount of 'spring back' and in the end would need to fire up the forge and hammer them flat when red hot on the anvil. In practice this one came out rather surprisingly well 

[awemawson]

Having the flail tilted up as it is gave me an opportunity to see how much play there is in the main flail shaft. Sure enough it is major - the bearings must have collapsed like those on the roller as I can lever the shaft up and down a significant distance. No doubt they will be fun to remove - if the bit of the shaft that the inner race seats on is badly worn (as is the case with the roller) then ingenuity is going to be heavily taxed to find a solution as I can't swing it in the lathe (too big).

In the case of the roller I have a fall back plan of cutting the ends off on the band saw, re-machining the ends as they will now fit in the lathe, then welding them back. However I don't think I can use this approach on the flail shaft - any eccentricity and it'll vibrate the whole thing to bits. 

[awemawson]

I grabbed a few minutes before lunch and squashed the rest of the flappy plates. Had to wack them with a sledge hammer to get them roughly flat to go in the press. They must be very much tougher than mild steel as they are hard as anything. Pleasing result though 

[awemawson]

So hanging around waiting for cottage guests to arrive, I may as well undo the 'skid pivot' bolts - these are M20 HT bolts that the skid & roller assembly pivots on to set the height of cut - skids need to come off to remove the rear roller and as the pivot bolts are uppermost at the moment they may as well come off. Gloves on so as to be ready for handshakes when people arrive.

Well no, not quite so easy  These bolts have been soaking with 'Plus Gas' for a couple of weeks but really didn't want to come off - eventually the left hand one unbolted with a long tube on a breaker bar, but even with heat the right hand one resisted my not inconsiderable mass on said bar.

Time to bring out the big guns - nice big hydraulic nut splitter (these nuts are 30 mm a/f) - nut cracked with a satisfying 'ping' and then unscrewed leaving a nice clean thread on the bolt - except where the skid has been pivoting and worn a big land. So will need replacing anyway.

I've no doubt if I'd wheeled in the oxy-acetylene and got it glowing it would have come off, but it's a heavy old big bottle rig 

So when time permits I can bring the fork lift in and re-position the flail to unbolt the adjustment end of the skids (skid has a single bolt and 10 mm thick side of flail has multiple places the bolt can go - again M20.

[awemawson]

A bit more dismantling this morning. First I needed to roll her over to get at the roller and the skid mounts.

Now this is the first time I've got it in a position where i can turn the roller for inspection - as expected the one dent visible as she was sitting is not the only one, and probably if I can source a suitable bit of heavy wall tube (135 mm o/d by 2 metres x at least 3 mm wall) I'll make a new one.

One 'good thing' is that oil has leaked from the gear box as it's been sitting in the wrong attitude, so at least it means there WAS oil in the box so it stands a chance of having survived 

[awemawson]

So first thing to do is unbolt the skids to release the roller and it's bearings - again 20 mm bolts unbelievably tight. Again I got out the nut splitter, but this time the nut won and the thread on the hydraulic nut splitter stripped  - another thing to mend.

This meant I had to bring out the oxy-acetylene - so rather than move the full size cylinders I transferred the cutting torch to the Portapak which made short work of loosening the nuts.

[awemawson]

So with the skids off and the knackered bearing assemblies off, the roller was free to remove - oh boy are the shafts worn 

This confirms me in my belief I'll make a new roller.

The bearings are a standard RHP item but seem to have had a grease seal of some sort mounted on the 'inner' face of the skid - the shafts are so worn it's difficult to see what was there originally.

... so it's one step forwards and one back - but that's always the way with a refurbishment 

[awemawson]

So no point in procrastinating - may as well find out what other horrors are lurking waiting to trip me up 

We have covers hiding both ends of the flail shaft with bearing housings and belts, and a cover concealing the jack shaft that drives the 90 degree gear box - lets have 'em off and have a look-see 

[awemawson]

Now although the main flail shaft bearings have collapsed and lost their ball bearings, the inner race at both ends seems intact, so hopefully the actual shaft will be ok to accept another bearing - lucky as I have no idea how I'd machine a 7 foot long shaft with floppy bits sticking out 

Again they seem to be a standard RHP item albeit rather expensive at a first investigation.

A close look at the actual flail shows that someone has had a lucky escape - obviously ran over some barbed wire and it just wrapped round the flail rather than tearing the driver to shreds 

The Jackshaft bearing and U/J's actually don't seem too bad on a brief examination.

[awemawson]

So the shopping list so far:

2 metres 135 mm o/d heavy wall (3 mm minimum) tube (5-6 inch would do) - roller
2 off SFT5-MSFT2 bearings (Roller supports)
2 off SF10/65 bearings (main flail shaft)
4 off SPB1600-5V630 drive belts (may need to be a matched set)
2 metres x 300 mm x 5 mm canvass re-inforced rubber conveyor belt (Chaff guard)

Numerous nuts and bolts

Big tin of Yellow paint
Big Tin of Primer

[awemawson]

A bit more 'progress' (is that the word when pulling things apart  ) today. First I pulled it out of the work shop and ran over it with the steam cleaner, especially around the bearing housings and gear box where it was hard to see what was supposed to be there and what was congealed accretions  It didn't all come off, but at least the nuts and bolts were now visible.

Brought it back inside (it's a dodgy thing to 'rig' - it swings all over the place) and removed the right hand bearing housing. The outer race was vaguely intact but cracked. and the inner race is still on the shaft and no doubt will entertain me getting it off. I could possibly get away re-using the housing with a new 'insert', but they seem to be 2/3rds of the price of the whole thing so not sure it's worth spoiling the ship for a h'pence of tar. (OK not a h'pence in this case - £120 each plus VAT - well they are 2.5" bore self aligning  )

Then I set too slackening the belt tensioner spring arrangement to allow me to remove the four drive belts. This will let me pull the Taperlock pulleys off and get at the left hand bearing assembly.

Now the belts are off I can assess the 90 degree gear box. Negligible back lash, but the output shaft bearings are noisy. Probably worth replacing all four bearings and two oil seals while I'm in there.

[awemawson]

The steel for the roller arrived today - 139.7 mm diam by 5 mm wall thickness - or in the proper units it was made in 5 1/2"  o/d - good stuff this metrication 

Now to buy the (just under) 2 metres that I needed as a cut length was the same price as buying the entire 7.5 metre length, so no point in not doing but for convenience I got them to cut the 2 metres off before delivery.

...so now I have a 5.5 metre 'offcut'  No doubt uses will crop up over the years to come.

The full length was 124.5 kG's of steel so great fun to manoeuvre single handed.

[Jo]

...so now I have a 5.5 metre 'offcut'  No doubt uses will crop up over the years to come.

Maybe you should have got them to cut it into two 2m lengths, so you had a spare  .


5 1/2" with 3/16" wall thickness..... could make a few model engine flywheel rims out of that 


Jo

[awemawson]

If you need any I can slice it off on my horizontal band saw

[PekkaNF]

Wonder how those bearings were protected from grass and grit - inside of the rotating thingy...We have that sort of stuf and unless it has pretty big "deflector" or shiels bearings et.al will be filled with debris in no time.

Pekka

[awemawson]

They are shielded bearings, the main flail shaft has a housing that surrounds the bearing on the inner side, and the roller has a secondary seal on the inner side of the skids but it's exact form is not obvious due to gross manglement 

Today I was hoping to remove the Jackshaft to allow me to get the 90 degree gear box out. However the splined output shaft of the gearbox is thoroughly stuck onto the yoke of the first universal joint. It should just slide - those holes that you see in the yoke go all the way down to the bottom of the shaft spines. Application of heat from the oxy-acetylene torch and pressure from a 'hydraulic wedge so far haven't got it to move one iota 

Got me a bit stumped - it's soaking in PlusGas at the moment but I don't hold out much hope - and it will make a nasty flaming mess next time I take the torch to it, which I surely will have to.

[RobWilson]

Andrew whats that bunker looking building in the background of the "on trailer " photos ? 

Rob

PS    if you used photobucket I would not have to click on every photo to make them large enough to see