Another foolish flail mower adaptation

[Handy Don 12,103]

Some time back @jachady posted his project with a Haban flail mower. That’s what inspired me to start my own crazy project. 
His was already belt-driven but connecting it to the WH took a bit of creativity. I recently scored a Haban 314 or 318 36” flail mower in remarkably good shape (the PO hacked the ID plate though) but it was originally made for a Bolens 1050 with a front PTO. A gearbox turned the rotation. 

I’ve stripped off the Bolens mount and drive hardware (I’ll post some of the bits for sale here and on the Bolens Forum—the gearbox looks like the one used on some sickle mowers). I am making an adaptor so that with some salvaged parts off a dead single-stage snowblower I can mount it to the front attach-a-magic. I’ll also be adding a pulley coupled to the mower drive sprocket and using the snowblower spring-loaded idler/tensioner on the drive pulley. 
Now for the kicker. The tractor is stored for the winter at a summer camp hours away so I cannot do any trial fittings for my winter project. I’m trusting the measurements I have but as I get into this I realize I missed a couple things. I’m hoping someone with a 300 or 400 close to hand can take and share some measurements for me and, even better, lives near enuf for me to drop by for some trials! I’m 35 miles north of New York City. 

Here’s what I need:

1. The diameter of the outer PTO pulley so that I can properly size the mower pulley. Clearance for this pulley “drives” repositioning the mower’s chain final drive to maintain alignment. The Bolens used a heavy and long universal jointed shaft that there isn’t room to adapt. I’ve scoured the forum and parts manuals but this pulley diameter is never mentioned!
2. The height from the ground to the center of the attachment’s support bar when it is locked in the attach-a-magic so I can align the mower height. 
3. The clearance needed between a fully left- or right-turned 8” front wheel with turf tires to an attachment directly in front of the tractor. I want the mower as close as possible but being able to make turns without scrubbing tire is useful!

I’ve attached a couple of images of the start of the project. More as I progress. 
Thank you and best regards. 
 

[Jhook 849]

I have my 315-8 am more than happy to take some measurements tomorrow 

[Ed Kennell 37,979]

Are you planning to raise and lower the mower using the snow blower push rod system?

[ebinmaine 67,151]

[SylvanLakeWH 25,454]

1 hour ago, ebinmaine said:

 

Me too...

[Pullstart 62,721]

Great idea!  Also, 

[CCW 1,291]

My 312 is in my shed and I am about two hours from you according to Google maps.

Edited September 29, 2020 by CCW

[Ed Kennell 37,979]

Are you planning to raise and lower the mower using the snow blower push rod system?

 

Here are measurements from my 417A.

Pulley dia.= 4.5"

 

Attach-a matic pin to ground = 13"

 

Attach a matic pin to front of turned wheel = 8"    It looks like 7" on the pic, but it measures 8".

 

[8ntruck 6,972]

Neat project.  

 

We've got 20 acres of woods in Ky.  Eventually, we will also have a house there.  I'm thinking that a flail mower will be a good tool to develop trials on the property.

[Handy Don 12,103]

Thank you @Ed Kennell for the exact dimensions I needed. And with images!

 

The mower spec calls for the drum turning at 2000 rpm and our engines are typically 3600 rpm full out so I need a 1.8:1 reduction. PTO at 4.5” means 8.1” on the mower. (Ok, a bit bigger than I’d hoped. Fitting that size pulley will take some extra work. Snowblower pulley is only 5½ or 6, I think.)

Lifting

My initial plan is to use the lift bar but I am concerned about force and leverage. On a blower it attaches only an inch or two from the ground; on the mower, where the cutting height is up to five inches making an attachment at the rear edge of the drum that much higher. Those inches reduce the lift bar’s leverage advantage. it’ll take a lot more effort to lift the attachment putting more force on the implement lift arm pivot and the front attach point. (I’m estimating that the two attachments are roughly the same weight— a lot!)

 

Side note: The image attached here shows one front support arm and it’s caster wheel. Spacers on the wheel’s pivot shaft go above or below the support arm to lower or raise the cutting height. 

 

I mulled the idea of a snowplow frame but that would drastically reduce the tractor’s over the ground clearance and the area I’ll be mowing is rough ground. Also a lot bigger to store. 
 

Right now working on a design that uses a coil compression spring to take part of the hoist weight and make the lift bar viable. It uses a lever to “load” the spring after mounting the mower. It’ll be anchored either low on the front attach point like a mule or else at the mid-mount, depending on the force it needs to bear. 

Testing

Kentucky might be a mite far to go for a test run 😉. Connecticut might be easier. I appreciate the offers, though. 

 

Kinda long post, sorry!  Again thanks for all the help and interest. 

[wallfish 16,963]

11 minutes ago, Handy Don said:

PTO at 4.5” means 8.1” on the mower. (Ok, a bit bigger than I’d hoped. Fitting that size pulley will take some extra work. Snowblower pulley is only 5½ or 6, I think.)

A smaller drive sprocket will help get you there without going huge on the pulley stuff. .

Cool project!

Edited September 30, 2020 by wallfish

[Handy Don 12,103]

I should add that @jachady didn’t have a lift. He kept it always on the casters. 
Also, part of my mount design lets me adjust the height of the back of the mower. 
Blowers don’t need this as their height adjustment maxes at an inch or so. 

[wallfish 16,963]

1 minute ago, Handy Don said:

I should add that @jachady didn’t have a lift. He kept it always on the casters. 

Did the same with a heavy rotary broom and worked out fine because of having the casters

[Handy Don 12,103]

Excellent point on the sprocket, @wallfish. Sadly it is a part unique to the mower and I’m reluctant to try to build a new one but I will give it some more thought. It may be net easier. When I have it apart I’ll post pictures. Right now drum and drive sprockets are 35-tooth. 

[wallfish 16,963]

2 new flange bearings and a new shaft for your new drive pulley connected to your new smaller sprocket? Killing 2 birds. LoL

Just kinda "think'n out loud" off the top of my head. I love these kind of projects

Edited September 30, 2020 by wallfish

[Handy Don 12,103]

Probably can repurpose both of the existing flange pulleys. They are ¾ shaft.
The sprocket is welded to shaft along with spacers to keep it centered.

 
I was thinking along the same lines. Keep the outboard flange bearing in place and move the inboard one to a flange I already have to add about 10 inches in from the chain side of the mower so it is near the PTO driven pulley to give good support. I have a ¾ shaft and 5 1/2 pulley from the snowblower. A new 24 tooth drive sprocket ($35 from Grainger) will get me the RPMs I need. Now to measure all to see if it lines up. Etc. etc.  

[Handy Don 12,103]

So I did some follow up on the suggestion by @wallfish to rethink the chain end as I finally got time to disassemble that part of the drive. 
With a 5.5” pulley and a 24 tooth sprocket and the existing 80 tooth #40 chain I get the right RPMs. 
As for getting the clearance for the pulley and getting it aligned with the sprocket, I think it’ll work. The mount for the flange bearing at the chain end will need a minor mod to bring the sprocket away from the mower body by about 1.25” and can use a smaller chain guard (instead of a harder mod to get 2.5” plus a bulky chain guard). Using the smaller sprocket lets me accommodate the now-longer chain line with the existing chain.

I won’t need a bearing at the inboard side of the chain housing—it’ll now move over onto the new bearing support flange near the pulley which can be slightly shorter and less beefy.  That shorter size also makes it easier to manage belt wrap and tensioning in the belt part of the drivetrain.

So thanks, @wallfish for causing me to give it another look!
Other good news was scoring a soft copy of the mower manual!  It’s a Haban 503A. I’ve attached a page here.
Parts 19-27 and 29 are the Bolens shafts and gearbox. About 35 lbs. I won’t need and this is what I’ll post in the for sale classifieds.
Part 42 is the custom sprocket jackshaft that I won’t reuse. In the attached pics you can see the clever design—strong, easy to manufacture, and economical on parts. It is a machined shaft with a keyway and throughbolt hole for the universal shaft drive end, a bearing space, a shoulder to which is welded a plain sprocket, another bearing space, and finally a threaded end hole for a bearing retainer hub bolt.
Next up are templates for the mount and bearing flange support I need for the metal fabricator. 

[wallfish 16,963]

On 10/1/2020 at 8:41 PM, Handy Don said:

So thanks, @wallfish for causing me to give it another look!

Yeah, i'm a pain in the @$$ when it comes to this kinda stuff. Always throwing it against the wall to see what sticks.

Certainly seems like you got it figured out, so looking forward to seeing the progress.

Look through this site, a 3/4" finished bore 24T sprocket is $12.70. They have lots of good things to build stuff

https://www.surpluscenter.com/Sprockets-Roller-Chain/Roller-Chain-Sprockets/Finished-Bore-Sprockets/?page_no=1&fq=ATR_Bore_Fractional:3/4\"&fq=ATR_Teeth:24&fq=ATR_PowerTransPitch:40

Edited October 3, 2020 by wallfish

[Handy Don 12,103]

Got distracted by a Craigslist ad for an ‘88 518-H with a tired but functional 42” SD for $375. We dickered and I bought it. So now I have a “reference” unit at hand—and an extra workload. The 518 needs a good tuneup, some rust abatement, a wiring check, and front tires and the deck will need some patches but I’m satisfied I got a good deal. Come spring it’ll replace the 310-8 that was the original target for the flail.  More oomph and larger tires will give me more confidence in the flail mowing use case for sure. 

 

Learned that while the outer PTO pulley is 4.5 inches across, it is a very deep “V” and its effective size is 4” (measured this via belt travel distance over a number of rotations). This, plus knowing that with a high-torque 18 hp Onan I can run a somewhat lower engine speed (say 3300 instead of 3600) to mow, I don’t need as much RPM reduction in the drivetrain.  With a smaller pulley and larger sprocket and shorter chain length the mods are even simpler. New metal fab templates today! Sometime delay works out well!
 

Lastly, was looking at the lift mechanism on a two-stage snowblower and saw that it uses a short push bar working though an L-shaped lever pivoting on an extended front attach-a-matic bar and that the blower frame itself pivots on the mid hitch. I’m going to start without a lift on the flail but it may prove useful to be able to lift it to ease maneuvering on rough ground. Thinking continues here. 

 

[Handy Don 12,103]

Hello to everyone,

Been going round and round working on designs for attaching the flail to the tractor. Just when I think I’m done and am reviewing the details, I see where it won’t work. 
Finally bit the bullet and decided that this will not be a reversible job. Do it right or don’t do it at all, my daughter counseled. Smart advice. That let me eliminate some thorny constraints. 
Other likely users made it clear they expect it’ll have a lift in the first iteration and their logic is sound. Okay. 
So we are now at the “sketched out and it looks good” stage again and I’m (hopefully) going through the details for the last time as I make the materials list. 

Meantime I’ve set to work on examining the flail closely looking for worn or broken bits that would need attention. After getting it up on a cart and turning it over so I’d have good light a wire peeking out caught my eye.

Tugged with vise grips but didn’t budge.

Long story short. Removed the drum and found this:

 

It seems a previous owner tried to mow a heavy wire fence (the plastic coated wire kind). And  by golly it mostly worked!  I imagine it made one heck of a racket. Now I know the cause of a couple missing and broken flails and the well chewed cutter bar.

Lesson: avoid mowing fences. 
Onward!

[wallfish 16,963]

He made an edger, Ingenious!

There just so happens to be an extra lift bar for a 2 stage blower in my extra parts pile. It's yours if you want it. That might save a bit of time figuring out the bends and making the pivot ends. The lift parts you have circled are fairly easy to make.

[Handy Don 12,103]

@wallfish, it was a bit beyond edging, don’t you think? And thanks for the offer. I may come look just for a chance to meet.  
Actually on my list is to estimate the tolerable range of vertical motion of the flail. It has to be able to go a couple inches below level through dips in the ground and when lifted it should get at least four inches above the highest cutting height (4.75”) so I need at least 10 inches of travel and it has to float so the lift lever doesn’t “flail” around and hurt someone.The lift mechanism’s longest push/pull throw (using the lowest hole 5” from the pivot and not recommended for any attachment I’ve read about) is 4.5+ inches. Load and range of motion say “Don, your users are not bodybuilders, you need a lift assist spring on that gadget.”  Yep. More calculations.  

Today went by in other pursuits helping friends so tomorrow back to detailed drawings checking dimensions, interferences, and clearances.  
Debate now on the flail is since its apart, do I paint it or let it be. Clearly some bits will need it due to exposing metal at the welds and the new parts, of course. Finding a close match won’t be easy. And I don’t have (or want) a spray gun and booth. It’s gotta come in a spray can!

The outer shell looks like a tool that’s been worked and shows it in a quite pleasing way. Letting’ that one simmer. 
 

[Handy Don 12,103]

@wallfish, what is the length of your 2-stage blower pushrod?  Does it expect a flag at the tractor end? Private message me anytime, if you wish. Thanks!

 

I thought I was finished with a full-scale working mockup in cardboard and dowels of the fully re-designed tractor-flail connection that included all the "user requirements"

• lift-enabled via standard lift mechanism,
• spring assist for lift,
• correct angle of attack when mowing at all heights,
• good ground clearance for travel,
• handle dips as well as rises in terrain,
• easy attach/detach via Tach-a-Matic (front + mid)

Then a new brand new requirement came in -- that it work with a swept axle 520-H chassis. I'll need to lengthen the arms a couple inches to clear the front wheels and may need a stronger spring to offset the longer moment arm.  Once the model gets updated I'll post a video and maybe even plans.  I could see this mechanism, working for a simple "wheelbarrow replacement" type front bucket that had a manual hold/dump actuator--a poor person's FEL--that didn't need a high lift.

[wallfish 16,963]

Although it doesn't appear "beefy" enough, it works well and don't ever remember hearing of someone bending one.

No flag, just pins on each end. The float action is achieved from the slot 

 

 

[Handy Don 12,103]

Thanks again, @wallfish. This length is very close to what I arrived at working backwards, but I don't have the funky bends in mine! Today I'll look again and see if it makes sense to adjust my work to incorporate this (and take you up on your offer) or just fab a new one.  

The image we shared hid the "float" slot, but now that you point it out I get it--clever engineering there.  The one thing that I'd like to see up close some day is how the blower lifts evenly with the single, off-center pushrod and lift arm.  I suspect it has to do with balancing the two lift assist springs.

Keep well.