Rears SPF Flail Mower

winesalot

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Jul 14, 2016
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Chelan, WA
Found a 72" Rears SPF flail mower on craigslist for $1500. Seller did not include the pto shaft in the sale. I rotated the unit and all bearings/gears felt OK so I bought it. Got it home, bought a new pto shaft, and hooked it up to the L4701, When I engaged the pto the mower shook so violently that I thought it would throw me off the seat. I quickly shut it down, unhooked the mower and rolled it into the garage on a couple of furniture dollies. The pictures below show what I found...lots of missing d-rings and blades. Maybe a bit out of balance? LOL Parts are on order and I am confident it will work well when reassembled.
 

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D2Cat

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Maybe that's why the seller did not include the PTO shaft, the buyer may want to hook it to his tractor for a demonstration.

I'm sure you can get it going the way it should, but one should not buy an implement without looking at the moving parts to be sure they are all there, and adjust the price accordingly!

An excellent source for any flail mower parts is Flail-Master at 800-251-4020
 

winesalot

Member
Jul 14, 2016
152
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Chelan, WA
Maybe that's why the seller did not include the PTO shaft, the buyer may want to hook it to his tractor for a demonstration.

I'm sure you can get it going the way it should, but one should not buy an implement without looking at the moving parts to be sure they are all there, and adjust the price accordingly!

An excellent source for any flail mower parts is Flail-Master at 800-251-4020
Could be but the two brothers selling this were taking over a business from a dad who had come down with Alzheimer's and were selling off a bunch of equipment the dad had laying around. I doubt there was manipulative malicious intent but rather they had no idea what was wrong with it. At the price I paid I was willing to repair quite a bit and felt it was a reasonable risk. I am still very happy with the purchase I was simple sharing with all of you.

Thanks for the tip on Flail-Master, I'll check them out.
 

North Idaho Wolfman

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I have been a huge flail fan from first time I ran one.
They can take care of a lot of nasty situations with the least amount of work.
And I would think in a vineyard it should work great for you.

Couple things to note:
It's going to take a few passes gradually lowering it to, one, get the landscape set for the flail (knocking off the high spots), and two, to get it set to a height that works great for you.

Be very careful if you have any rock and running it when it's too dry, these suckers can start a fire in dry material very quickly, the blades spinning act like a striker on a flint stone!
 

Dave_eng

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My experience with a MOTT flail was missing knives meant bad vibration.

Also, post photos of your pto shaft. Unlikely the problem but one that is not indexed will vibrate like crazy.

I think there was another drive shaft on the unit so post photos of it was well as something funny there is more likely than the new pto. It was a new pto right?

You cut it to the proper length with the correct overlap?

Back again. I looked at the second photo more closely. There are no knives and rings on one side of the rotating part. This is a serious imbalance.

Take all knives and rings off and I will bet your vibration is gone.

Dave
 
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winesalot

Member
Jul 14, 2016
152
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Chelan, WA
My experience with a MOTT flail was missing knives meant bad vibration.

Also, post photos of your pto shaft. Unlikely the problem but one that is not indexed will vibrate like crazy.

I think there was another drive shaft on the unit so post photos of it was well as something funny there is more likely than the new pto. It was a new pto right?

You cut it to the proper length with the correct overlap?

Back again. I looked at the second photo more closely. There are no knives and rings on one side of the rotating part. This is a serious imbalance.

Take all knives and rings off and I will bet your vibration is gone.

Dave
I'd bet a fairly large sum of money on the missing blades and d-rings being my issue. I am certain I cut the pto shaft correctly and the pto shaft connecting the gearbox to the drive pulley has good u-joints. Not much else to vibrate.
 

winesalot

Member
Jul 14, 2016
152
6
18
Chelan, WA
I have been a huge flail fan from first time I ran one.
They can take care of a lot of nasty situations with the least amount of work.
And I would think in a vineyard it should work great for you.

Couple things to note:
It's going to take a few passes gradually lowering it to, one, get the landscape set for the flail (knocking off the high spots), and two, to get it set to a height that works great for you.

Be very careful if you have any rock and running it when it's too dry, these suckers can start a fire in dry material very quickly, the blades spinning act like a striker on a flint stone!
I am looking forward to using it as well. Used them when I worked for WA DOT and like them a lot.

Definitely a plus when we plant the vineyard to have the ability to throw all the prunings in the grass between the rows and then make them disappear.

Thanks for the operating tips. I plan to take my time figuring out the height adjustment on this beast.
 

Jeremy

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Apr 3, 2024
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I know this post is 6+ years old but hopefully someone is still interested...

I have a Rears SPF that is virtually identical to the one pictured above (winesalot). I am also getting a wicked vibration when I start the PTO. The bearings all look/feel good on mine and all cutting blades are in place. The local dealer diagnosed it as a bent main shaft and wanted $5k to fix it. I've read that you could possibly pull it out and take it to a driveline shop to straighten it.

Question for everyone: How do you get it out? I can pull the bearings off but the main shaft is longer than the frame. Is there anyway to do it without cutting a notch in the non-belt side of the frame?