Flail mower/mulched head question

The Learner · Mar 28, 2018

hey guys

Been looking into flail mowers
Now here’s a left of centre question

More hammers or less?
What’s better?

More hammers to hit more frequently? Does it make smaller pieces

Less hammers to hit more material?
Make the process faster?

Does one take more horsepower than the other?

Does one work better than another as far as material capacity or end result?

Just trying to gauge why none are the same

Cheers T L

DIYDAVE · Mar 28, 2018

I got the hammers, not knives, on the woodmaxx, I just got.

Works pretty good on light branches, briers I mow.

there were no options on how many hammers you could order, just hammers or knives.

HP increases, as the diameter of the circle the hammers swing in, increases...

I looked at the drive end, the more belts the better, IMHO.

I suspect you are looking for a ssl, but to understand the basics, I would recommend you go to woodmaxx's site, and watch a few videos

Here is what I ended up with, fer a Kubota B2100(20HP), works great, no complaints:

The Learner · Mar 28, 2018

Definitely getting hammers not knives

Actually looking to go on mini excavator

Reason I ask hammer numbers
Tractors have nearly twice as many as an excavator
Why?

I’m intrigued as to required horse power if that makes sense

Tones · Mar 28, 2018

The Learner said:
Definitely getting hammers not knives

Actually looking to go on mini excavator

Reason I ask hammer numbers
Tractors have nearly twice as many as an excavator
Why?

I’m intrigued as to required horse power if that makes sense

Compare the widths, that will be the difference in the number of tools. Most manufacturers stick to their own pattern. My AHWI forestry mulcher has 30 teeth on a 5ft cut, next size up has 36 on a 6ft cut

DIYDAVE · Mar 28, 2018

The Learner said:
Definitely getting hammers not knives

Actually looking to go on mini excavator

Reason I ask hammer numbers
Tractors have nearly twice as many as an excavator
Why?

I’m intrigued as to required horse power if that makes sense

You will need to know the Flow (GPM) and pressure(PSI) that your excavator hyd system operates, to properly spec a flail mower for it. Its a little easier, on a tractor, gear driving an attachment(just need the HP of the tractor) I chose the smallest for mine, cause the tractor is 20 HP, if you look it up, though, its more like 16, for a hydro. I'd start hitting youtube, and looking at what's out there. Or go to a timber/forestry show, where you can see them in action! Good luck!

The Learner · Mar 29, 2018

Thanks for the responses guys

I’ve got a 302.5c cat
With about 21lpm at 180bar
And 35 litres at 160bar
56lpm full flow

Main reason I come into these questions an excavator flail for my machine is .7-1m
A 1m flail for an excavator has 10-11 flails (16-25hp tractor)
A 1m for a tractor has 16-18 flails

A flail built for an excavator costs $4k and up from there
A flail for a tractor starts at about $1k and up from there

Is it worth trying to build a tractor flail into an excavator one
Or is there something stopping that from working

Cheers The Learner

Hobbytime · Mar 29, 2018

I hove both types of flail mower, knives basically for grass and hammers or duck feet for brush and heavier material.. the more hammers the more HP needed as you are cutting more brush with more hammers... tractor is designed for PTO no hydraulic motor on the actual mower and excavator mower has hydraulic motor on the mower, my guess to the less hammers on the excavator one is the amount of flow and stress put on the mower frame itself, otherwise the excavator mower may end up being much heavier( more than the excavator can easily maneuver around) with more hammers to keep it in one piece...Im sure you can fabricate one from a tractor to an excavator mower but by the time you add up needed parts and fabrication it may cost you more in the long run and then you have the saftey issues for the fabricated one, if that thing lets loose you can kill someone or yourself...

The Learner · Mar 29, 2018

That’s just the thing hobby time
a tractor one 1m long is lighter than an excavator one .7m long

I’m trying to work out if more hammers make it easier to cut because each hammer would take a smaller chunk if that makes sense

All I can see having to do is remove the pto angle drive from the top of the flail and mount a hydraulic drive motor in its place

The remove the three point linkage and swap it for a head bracket

Does anyone have experience in converting a tractor attachment from pto to hydraulic aux

Tones · Mar 29, 2018

Heck Learner, a hydraulic motor and hoses will cost more than 3 grand then you'll have to put priority valving on the excavator all before the fabication starts so it's heaps more than buying a mower off the shelf.
BTW the hydraulic specs don't check out. You need to find out what the spec's are for the ancillary line

The Learner · Mar 29, 2018

From my experience with earthmoving equipment I should be able to find a suitable drive motor for around $500-$1000 bucks
Hoses are easy and cheap

My machine doesn’t need a priority valve I’ve already had the flow meter hooked up and aux has priority
Machine still operates smooth and fast enough to flail mulch
With the aux suppling a full 21l at 180bar

Those specs I listed before aren’t from a website and they aren’t for the whole machine
They are what I personally tested on my machine’s aux before I started looking into this whole flail mower idea

DIYDAVE · Mar 29, 2018

The Learner said:
That’s just the thing hobby time
a tractor one 1m long is lighter than an excavator one .7m long

I’m trying to work out if more hammers make it easier to cut because each hammer would take a smaller chunk if that makes sense

All I can see having to do is remove the pto angle drive from the top of the flail and mount a hydraulic drive motor in its place

The remove the three point linkage and swap it for a head bracket

Does anyone have experience in converting a tractor attachment from pto to hydraulic aux

I built a bush hog, snow blower, and flail mower, to fit my ASV RC30. Used 3 point hitch equipment, and put direct drive hyd motor, on the BH, Chain drove the other2. My advice is this, when you spec a motor, step the RPM up a little, PTO implements are rated for 540 RPM, but hyd motors always seem to run a little slower, than advertised, IMHO. If you are direct driving the flail head, put a shear bolt in the connection, its cheap insurance, if you hit wire, and wrap the head to the point of a stall. Most of the components I got, I got from Surpluscenter.com, in Nebraska(even if you don't use them, they have excellent tech assist pages, and Hydraulic formulae pages). You will prolly have a similar type co, in Oz. Final thought, take heavy sheet metal, and replace 3PH equipment's thin tin, I made the Bush hog outta 1/4" sheet metal, and haven't regretted it...

Tones · Mar 29, 2018

The Learner said:
Machine still operates smooth and fast enough to flail mulch
With the aux suppling a full 21l at 180bar

The pressure and flow rates don't compute to the engine power. What you have listed there requires 63kw's and the machine only has 18.5kw's according to Ritchies Spec's

The Learner · Mar 30, 2018

Thanks Dave
My plan is to keep the belt drive for a safety/ protection the belts should/will slip in that scenario and therefore protect the motor

Thanks Tone
Well what happens on paper is “projected outcome” actual figures may vary
Now I understand that there’s big difference
But if it didn’t happen I wouldn’t of said it
The machine does have a full size variable piston pump unlike most other 2.5’s with a fixed gear pump stack
So thats how it can “over compensate” (i think that’s the right word)

At 21lpm and 180bar
I could still function the machine fluently and gently without loosing any attachment power

And I have a comparison chart with the hydraulic performance of quite a few machines in various sizes and in comparison those numbers are close to correct

Thanks the learner

The Learner · Apr 6, 2018

Dave
I’d be interested to see some of your converted attachments
As far as how you have gone about making the hydraulics attach to the PTO

Tones
You seem to have a great understanding of the hydraulics on paper
Would you be able to assist with the sizing of an appropriate hydraulic motor when it comes time to purchase?

Tones · Apr 6, 2018

Happy to Learner.

DIYDAVE · Apr 6, 2018

The Learner said:
Dave
I’d be interested to see some of your converted attachments
As far as how you have gone about making the hydraulics attach to the PTO

Tones
You seem to have a great understanding of the hydraulics on paper
Would you be able to assist with the sizing of an appropriate hydraulic motor when it comes time to purchase?

Wish I could, not able to post pics...

Tones · Apr 7, 2018

The Learner, I must apologize to you over the pressure/flow calculation I posted above, it was very very incorrect. The pressure and flow you posted requires 6.3kw NOT 63kw.

The Learner · Apr 7, 2018

All good tones
Like I said on paper isn’t always correct and I tested is what I tested

You have more understanding of the paper side of it all than I do
I know the physical side of what happens at the couplers and what happens when I pull a joystick the pilot moves the valve and the pump comes on stroke but the numbers behind it all escapes me

Tones · Apr 7, 2018

I had to learn all this stuff when I purchased new was so overspeiced on paper it was not funny after it blew a pump to bits in less than 2000hrs.
www.brendsen.com.au has a lot of info on their website in the resources section.

The Learner · Apr 7, 2018

Ah knowledge from past bad experiences that is the best kind

How much it sucked to go through first time
You don’t want to see it happen again so you know the ins and outs of what to do and what not to do

I like it
Cheers The Learner

Flail mower/mulched head question

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