Hybrid Rotary Cutter Proof of Concept

[dadohead]

Every deck seems to require a different type of blade. I worked for a blade manufacturer. There were a couple of tests we did that simulated running across a stake, like a surveyor stake, or a fence post in the case of a forage harvester, yet the blades afterward needed to still function, and without breaking.

Yes, the 'stake test'. Part of the ANSI battery of tests. A solid (1"?) steel stake is fired up into each blade at a specified location. To pass, NOTHING can fall on the floor... including ANY deck part. Sometimes, adjacent blade(s) will unscrew themselves and fall on the ground: fail! Redesign blade joint! Big decks can cut the stake right off! The Euro version of the test fires a hollow tube. Some say a tougher test because the 'stake' bends over and contacts the blade continuously. Other ANSI mowers tests are: stop time, imbalance, and thrown objects (200 ball bearings, each launched into a chamber, fired out hitting a target, if ONE goes high: fail) Typically, stake test is done last because the deck is toast after that!

I was going to say welding on them sounds like a quick r&d thing to get it done, but then you went out and had some made.

Exactly.

 

[dadohead]

Would you recommend adding the baffle first or increasing the blade fin/wing?

Oh yeah: if deck cant shift... shift the LH rear tractor tire inward. See if the stripe disappears/improves.

 

[dieselscout80]

Oh yeah: if deck cant shift... shift the LH rear tractor tire inward. See if the stripe disappears/improves.

My tires are not adjustable per the ownership’s manual, so the baffle first?

 

[dadohead]

I'd shift the mower... if mower tongue is fixed, could you prepare a crossbar and bolt it to the tractor hitch? Hook up the mower shifted left? It will be the most impactful thing to do.

 

[350c]

I would think tow-behind mowers would be much harder on the U-joints than three point mounted models. For that reason alone, I would stick with the three point model, unless I really needed tow-behind because of the size.

Hey Runner, I would think just the opposite--the u-joints would stay more in a straight position instead of having to flex up and down when the 3-point is raised/lowered. There are definite advantages with being able to raise the 3-point, but I was able to raise the trail type I had with hydraulics to clear rocks, stumps, etc. There was a lot more vibration transferred to the tractor with the lift models; that can't be good on bearings, bushings, etc., and over time has to take its toll.

 

[350c]

Cost. Pull-type mowers require at least 2 rear wheels and external hydraulics to operate the lift. Since their driveshafts operate in 3d space, expensive CV joints must replace the cheaper cardan joints found in 3pt mounted mower driveshafts.

Thanks for the reply. From my perspective, the additional strains on the much more expensive tractor, especially lighter SCUT and CUT tractors, would eventually lead to greater costs than one additional wheel and better CV joints for the mower. But I'm not privy to info that I'm sure you are. Just from personal experience, when I was actually 'farming' with larger equipment (and it was a mountainside farm, not nice smooth fields), I always felt the trail type transferred a lot less vibration onto the tractor itself, thereby reducing the stress on the tractor and its' many parts. I currently have a 3-point but would trade it for a trail type in a heartbeat; "brush hogs" are made to withstand beating and banging, tractors not so much...
On a side note, the areas I've seen flail mowers used on here look more like the material had been knocked down more than cut but, then again, this isn't on nice smooth fields.

 

[Runner]

Hey Runner, I would think just the opposite--the u-joints would stay more in a straight position instead of having to flex up and down when the 3-point is raised/lowered. There are definite advantages with being able to raise the 3-point, but I was able to raise the trail type I had with hydraulics to clear rocks, stumps, etc. There was a lot more vibration transferred to the tractor with the lift models; that can't be good on bearings, bushings, etc., and over time has to take its toll.

Maybe depends on the property being mowed. When I mow my pasture, I set the height once and don't touch the rockshaft lever again until I'm done mowing.

 

[dieselscout80]

I'd shift the mower... if mower tongue is fixed, could you prepare a crossbar and bolt it to the tractor hitch? Hook up the mower shifted left? It will be the most impactful thing to do.

I was thinking about that very thing making a temporary extension to shift the hitch position to the left.

The term you used is back sweeping which I think means the blade is moving forward (ex., as the tractor is mowing) which is the same direction that the tires push the grass down.

Which leads me to this question is clock wise rotation is it as viewed from the top of the deck or when looking up from underneath the deck?

I think it would be best to just hook up and the mower with it raised up and observe the blade rotation.

 

[dadohead]

I was thinking about that very thing making a temporary extension to shift the hitch position to the left.

The term you used is back sweeping which I think means the blade is moving forward (ex., as the tractor is mowing) which is the same direction that the tires push the grass down.

Which leads me to this question is clock wise rotation is it as viewed from the top of the deck or when looking up from underneath the deck?

I think it would be best to just hook up and the mower with it raised up and observe the blade rotation.

"Back-sweep" is the portion of the blade going backward as the deck moves forward. This is typically the best cutting region on each blade. The deck (and tractor) is pushing the material forward as the deck moves through it. Easy for the blade to then "go against the grain" and cut cleanly. Blade pass frequency on my new cutter is 1.1"/cut @ 3mph... so each grass tuff gets appr 3 wacks. That's it.

Forward sweep is the weakest part of the cut! Grass bent forward, mower blade also going forward = grass NOT lifted. Note: most zero-turn mowers out there have one (at least) caster wheel out front that is repositioned farther to the side. Why? They are moving a tire track OUT of the forward-sweep region and into the back-sweep.

When a tire track aligns with forward sweep... the result is almost always "striping". It appears that is what your mower is doing (you didnt reply to my question about the tractor tire aligning to the stripe). I looked up your C114-1 and it detailed CW turning blades. From the images I saw on YouTube, their tractor tire was at the 11:00 position to the LH blade.... that's the forward sweep region. ITs GOING TO STRIPE! I dont think baffles or blades will fix it. I'd put my energies toward shifting the mower (or overlapping the passes to re-mow the stripes). Hope this helps! Randy

 

[dieselscout80]

"Back-sweep" is the portion of the blade going backward as the deck moves forward. This is typically the best cutting region on each blade. The deck (and tractor) is pushing the material forward as the deck moves through it. Easy for the blade to then "go against the grain" and cut cleanly. Blade pass frequency on my new cutter is 1.1"/cut @ 3mph... so each grass tuff gets appr 3 wacks. That's it.

Forward sweep is the weakest part of the cut! Grass bent forward, mower blade also going forward = grass NOT lifted. Note: most zero-turn mowers out there have one (at least) caster wheel out front that is repositioned farther to the side. Why? They are moving a tire track OUT of the forward-sweep region and into the back-sweep.

View attachment 3774346

When a tire track aligns with forward sweep... the result is almost always "striping". It appears that is what your mower is doing (you didnt reply to my question about the tractor tire aligning to the stripe). I looked up your C114-1 and it detailed CW turning blades. From the images I saw on YouTube, their tractor tire was at the 11:00 position to the LH blade.... that's the forward sweep region. It’s GOING TO STRIPE! I dont think baffles or blades will fix it. I'd put my energies toward shifting the mower (or overlapping the passes to re-mow the stripes). Hope this helps! Randy

Sorry hadn’t had time to hook it back up and measure it.

It is a 114” wide mower 57” to center. On my TC45DA the left tire measured from the center of the drawbar is 18” to inside and 34” roughly to the outside edge.

The streak seems be from almost the outside edge of the left tire to say 30” to most of the way to the outside edge of the cut, but not the whole way.

Next week I will hook it up again and see the actual measurement of the streak.