Rotary Cutter Rotary Mower - Plan B - Adjusting FRONT DECK HEIGHT with LIMIT CHAINS

jeff9366 · Jun 10, 2012

In an earlier post "Rotary Mower - Adjusting Rear Deck Height With CHAINS" I reviewed my successful attempt to use LIMIT CHAINS to prevent the REAR of my rotary mower from sinking until both mower skids contacted the ground. The limit chains maintained a 5" cut perfectly but blade height could not be adjusted. During my first mowing session at 5" it hit me: EUREKA!! in order to cut lower I would have to limit sink at the FRONT of the cutter, rather than the rear.

You may wish to read Plan A first, for background.

http://www.tractorbynet.com/forums/attachments/247814-rotary-mower-adjusting-rear-deck.html

Hence the title of this post: "Rotary Mower - Plan B - Adjusting FRONT DECK HEIGHT with LIMIT CHAINS."

Photo #1 is an overall view. Limit chains are attached to the front of mower 7/8" lift pins via 1-1/2" steel rings, to 5/16" Quick Links to 48" lengths of 3/16" (Grade 30) chain running up to 5/16" grab hooks attached via 5/8" pins through the fold bracket for the ROPS. Got it? Note Bungee cords to pull chains away from PTO shaft in remote chance chains should jar out of the grab hooks when cutter raised and chains are slack.

See Photo #2: The weak point is the Tractor Supply Co. 1-1/2" steel ring; just a 200 pound working load. Tomorrow I will order heavier gauge 5/16" X 1-1/2" stainless steel rings with working load of 750 pounds from Bosun Supplies in Maryland. There is not much "pull" on the chains. They are LIMIT chains not LIFTING chains. The 3-Point lift arms bear most of the weight. Heaving on the attached individual chains I guesstimate the cutter weight on each chain at about 50 pounds, in static condition, WITH MY EQUIPMENT.

See Photo #3: Several reply posts to my earlier thread warned against using the ROPS for securing the limit chains at the top. But the ROPS on my Kubota B3300 is massive and attaches directly to the tractor frame and it is only supporting additional chain pull of about 50 pounds on each side. I realize the stress may double or triple when mowing but that is still no big deal relative to the massive ROPS, in my opinion. (The chains are actually supported by the ROPS fold bracket, which is bolted through the ROPS.) If I become concerned I will replace 3/16" Grade 30 chain with 1/4" Grade 70 chain. Unhappily the grab hooks and pins have to be removed to raise or lower the ROPS.

In Photo #3 you will see a 5/8" locking collar securing the pin. A little Bee's wax on a CLEAN Allen Screw inhibits Allen set screw from backing out. The collar tightens the installation up and is a backup to the lynch pin.

The green cable tie marks the link which gives me ground clearance of 2-1/2" at front end on both sides and 3-1/2" ground clearance at the discharge (rear) end, on both sides. Nirvanna for short. Coarse adjustment is available by moving chain in the grab hooks. If I need fine adjustment I will add a turnbuckle in the middle of each chain.

Photo #4 is a discarded idea. I considered using this slider/glider and grab link rather than the grab hooks but the slider/glider is too wide, it would have to be cut or ground off to 1-1/2" width in order to fit within the ROPS bracket which has 1-5/8" clearance. I am staying with grab hooks for now, honoring the KISS principle.

Sheldon Hill Forestry Supplies Inc.: CHOKE GLIDER

Photo #5 is another discarded idea. I would have liked to attach the limit chains via grab hooks around the lower top lift pin but the chains would rub on the metal PTO guard cage and possibly bend it.

I hope this post helps someone.....'n Happy Hogging.

pacerron · Jun 10, 2012

jeff9366 said:
In an earlier post "Rotary Mower - Adjusting Rear Deck Height With CHAINS" I reviewed my successful attempt to use LIMIT CHAINS to prevent the REAR of my rotary mower from sinking until both mower skids contacted the ground. The limit chains maintained a 5" cut perfectly but cut could not be adjusted lower. During my first mowing session at 5" it hit me: EUREKA!! in order to cut lower I would have to limit sink at the FRONT of the cutter, rather than the rear.

You may wish to read Plan A first, for background.

http://www.tractorbynet.com/forums/attachments/247814-rotary-mower-adjusting-rear-deck.html

Hence the title of this post: "Rotary Mower - Plan B - Adjusting FRONT DECK HEIGHT with LIMIT CHAINS."

Photo #1 is an overall view. Limit chains are attached to the front of mower 7/8" lift pins with 1-1/2" steel rings, to 5/16" Quick Links to 48" lengths of 3/16" (Grade 30) chain running up to 5/16" grab links attached via 5/8" pins through the fold bracket for the ROPS. Got it? Note Bungee cords to pull chains away from PTO shaft in remote chance chains should jar out of the grab hooks.

See Photo #2: The weak point is the 1-1/2" steel ring; just a 200 pound working load. I will add a second ring, same size, on each side tomorrow. Then search for heavier rings or install 3/8" forged Eye Bolts to replace the weak rings. You could use 1-1/4" steel rings and still have room to attach the 5/16" Quick Links but the working load for the smaller rings is only 150 pounds. There is not much "pull" on the chains. They are LIMIT chains not support chains. The 3-Point lift arms are bearing most of the weight. Heaving on the attached individual chains I guesstimate the cutter weight on each chain at about 50 pounds, in static condition, WITH MY EQUIPMENT.

See Photo #3: Several reply posts to my earlier thread warned against using the ROPS for securing the limit chains at the top. But the ROPS on my Kubota B3300 is massive and attaches directly to the tractor frame and it is only supporting chain pull of about 50 pounds on each side. I realize the stress may double or triple when mowing but that is still no big deal relative to the massive ROPS, in my opinion. (The chains are actually supported by the ROPS fold bracket, which is bolted through the ROPS.) If I become concerned I will install a stiff spring as a shock absorber in the middle of each chain. Unhappily the grab hooks and pins have to be removed to raise or lower the ROPS.

In Photo #3 you will see a 5/8" locking collar securing the pin. A little Bee's wax on a CLEAN Allen Screw inhibits Allen set screw from backing out. The collar tightens the installation up and is a backup to the lynch pin.

The green cable tie marks the link which gives me a front deck height of 2-1/2" on both sides and 3-1/2" deck height at the discharge (rear) end, on both sides. Nirvanna for short. Coarse adjustment is available by moving chain in the grab hooks. If I want fine adjustment I will add a turnbuckle in the middle of each chain.

Photo #4 is a discarded idea. I considered using this slider and grab link rather than the grab hooks but the collar/slider is too wide, it would have to be cut or ground off to 1-1/2" width in order to fit within the ROPS bracket which has 1-5/8" clearance. I am staying with grab hooks for now, honoring the KISS principle.

Sheldon Hill Forestry Supplies Inc.: CHOKE GLIDER

Photo #5 is another discard idea. I would have liked to attach the limit chains at the lower top lift pin but the chains would rub on the metal PTO guard bracket and probably bend the guard.

I hope this post helps someone.....'n Happy Hogging.

A link back to your first try which you suggest folks read http://www.tractorbynet.com/forums/attachments/247814-rotary-mower-adjusting-rear-deck.html

I still think you are making a serious mistake attaching the chains from the ROPS to the mower. You have spent a lot of money on hooks, links, chain, etc. and have come up with a rig that will take a lot of time to hook up and unhook. Have you tried it in the field yet?
All you are really trying to do is keep your lower links from dropping.
2 of the little red chain slot hangers through the spare hole in your top link
bracket on the tractor with a long bolt. It doesn't have to be as large a dia bolt as the holes in your upper link bracket.
Run 2 chains from the front mower bracket or your lower lift links to the
chain slot hooks and your done. Take the other stuff back for a refund or use it someday for something else. As you said. KISS

pacerron · Jun 10, 2012

In regard to your statement "Photo #5 is another discard idea. I would have liked to attach the limit chains at the lower top lift pin but the chains would rub on the metal PTO guard bracket and probably bend the guard."

If you recall the yellow Woods chain hooks in the picture I sent you were bent on the end that attached to the outside of the upper link bracket. That keeps the chains from contacting the PTO cage. You could add a little piece of metal with a 20-45 degree angle bent in it to the bolt end of your red chain brackets and have a hole in the other end for the bolt or link pin to go through your center link bracket on the tractor, if using them straight causes any rubbing action.

jeff9366 · Jun 10, 2012

Glider will not fit where you suggest. The PTO metal cage, visible in photo #5, is directly in the way.

Not long to take off:
1. Remove lynch pin and collar then pull grab hook pin from ROPS bracket.
2. Pull attachment ring from lifting pin on mower when lift arm is off pin.

greg_g · Jun 11, 2012

Sorry to say, another bad idea. Every time you traverse a gulley or ridge, the front of the mower will dip/rise proportionate to the attack angle. I don't doubt the mower skids will be gouging the sod as your tractor rises out of a gulley. And the blades will likely end up cutting air as you start the downslope after crossing a ridge.

You seem to have a love affair with chain hooks. And assuming you're using adequately tempered steel for safety, it's not exactly cheap. Assuming same, you've almost certainly already spent enough on chain and hooks - not to mention time invested - to already have purchased proper limiter chains; the keyhole slot type I showed you in your other thread. Thirty bucks complete!

//greg//

pacerron · Jun 11, 2012

Jeff
We are not picking on your ideas it is just that you have not considered
the dynamic, unequal, weight shifting of an implement mounted behind a tractor versus your thoughts on static weight distribution.

A rotary mower with a single caster rear support is one of the worst to exert
continuous uneven weight change and pressure on the front mounts. Too deep a subject to get into here.

Your pictures appear that you don't even have any anti-sway locking devices
on your tractor lower link arms?
We hope, for you and your family's sake that experience will be a good teacher and not a crippler.
Ron

jeff9366 · Jun 11, 2012

My one year old Kubota has the factory, beefy, steel turnbuckles called CHECK CHAINS even though they are not chains. Mower sway is perhaps 1-1/2", which I set with the turnbuckles.

It is entirely FLAT in this part of Florida. I mow a lot of groundcover wild Muscadine grapes at 3" trying to kill them.

If I going into the woods to mow brush I set the cutting height up to 3-4" depending on conditions.

THE LIMIT CHAINS ADDRESS THE SLOW SINK ISSUE WITH THE PTO. LIMIT CHAINS SOLVE THE SINK PROBLEM AND RETURN MOWER TO EXACT MOWING HEIGHT AFTER LIFTING FOR A TURN.

Setting up every tractor with every implement is a case in itself. There is no REVEALED TRUTH.

I am happy with the setup; works fine, lasts a long time.

(Lordy!)

pacerron · Jun 11, 2012

In addition, the end of your PTO shaft that attaches to the mower has no guard tube over it or the U-joint. If one of your chains comes loose and gets caught up in the spinning shaft or u-joint, it will be "game over" for a lot of expensive equipment.
Always think safety and protect your back side/head from potential damage.

BlacknTan · Jun 11, 2012

greg_g said:
Sorry to say, another bad idea. Every time you traverse a gulley or ridge, the front of the mower will dip/rise proportionate to the attack angle. I don't doubt the mower skids will be gouging the sod as your tractor rises out of a gulley. And the blades will likely end up cutting air as you start the downslope after crossing a ridge.

You seem to have a love affair with chain hooks. And assuming you're using adequately tempered steel for safety, it's not exactly cheap. Assuming same, you've almost certainly already spent enough on chain and hooks - not to mention time invested - to already have purchased proper limiter chains; the keyhole slot type I showed you in your other thread. Thirty bucks complete!

//greg//

All constructive criticism from everyone, but I won't add any. I must say that I agree with the quoted post though. For $30 that setup is the way to go. My only regret is that I wish I had found those before I bought the setup from Woods... Which cost ALOT more, and designed for CAT 3 is waaaay overkill for my application.!

boggen · Jun 11, 2012

you can normally adjust the "tail wheel" of most rotatory cutters, buy undo pin or even a bolt. and adding washers. below or above the bearing that allows the rear tail wheel to spin. this increasing or decreasing the rear height of the deck.

picture from.... Double HH Quality Products - Don't Compromise... Demand Double HH

the limiting chains others are talking about. are much like the "stay straps" in above diagram. but instead of a bar it is a chain.

allowing you to still raise the rotatory cutter. and able to lower the rotatory cutter right back to were you want it.

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you also do not have any sort of "adjustable stabilizer arm bar/chains" and/or check clevis chains. to keep rotatory cutter from swing out and into your rear tires.

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looking back at picture and talk of the "metal guard" surrounding the PTO shaft. there should be adequate clearance for limit chains or stay strap bars/chains. that hole is there for a reason just below the top link connection on rear of tractor.

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you do not need to have rotatory cutter all the way up during transport, keep it a little bit off the ground all that is really needed. and if you need extra height during transporting rotatory while attached to tractor. adjust the "top link" on 3pt hitch.