Difference between heavy duty and medium duty rotary cutter

[dirtyj]

I am about to get a cutter and would rather have something that won't be stressed too much, so I'm opting for heavy duty vs medium duty (JD 709 vs MX7). I am mounting this on a JD 5205 that has 50 hp PTO rating.

Can someone please explain 2 things to me?

1: why does the 709 have a lower PTO hp rating (45 vs 50) than the MX7?

2: does the higher gearcase hp rating on the 709 answer my question?

I just want to be sure that I am not running into any issues and that the literture is correct.

Thanks for any help!

 

[rbargeron]

The gearbox rated horsepower is the power level that can be transmitted through the gearbox continuously. The stronger and heavier the design, the higher the hp it can handle without excessive wear or heat buildup.

The mower's PTO hp is the amount of power it needs to do the job. There shouldn't be much difference in required power for mowers of the same size cut. The lower power requirement for the heavier mower might be due to higher efficiency of its gearbox. But 10% is a big difference. Maybe just a mistake.

 

[sweettractors]

The MX series is showing some signs of giving problems. We sell the 7 ft Hawkline/International for $1995, This is a true HD cutter at a $1500 savings. I am not trying to sell you one, I can't ship it. Just showing you what a range of cutters are available. Ken Sweet

 

[MarkV]

The MX series is showing some signs of giving problems. We sell the 7 ft Hawkline/International for $1995, This is a true HD cutter at a $1500 savings. I am not trying to sell you one, I can't ship it. Just showing you what a range of cutters are available. Ken Sweet

Ken I was curious what the HP rating on the Hawkline gear box was. I thought most truly heavy duty rotary mowers ran gear boxes with 90 hp ratings.

MarkV

 

[peter_vii]

I am about to get a cutter and would rather have something that won't be stressed too much, so I'm opting for heavy duty vs medium duty (JD 709 vs MX7). I am mounting this on a JD 5205 that has 50 hp PTO rating.

Can someone please explain 2 things to me?

1: why does the 709 have a lower PTO hp rating (45 vs 50) than the MX7?

2: does the higher gearcase hp rating on the 709 answer my question?

I just want to be sure that I am not running into any issues and that the literture is correct.

Thanks for any help!

1. I think 709 has a more efficient geardrive to deliver the same cutting power with less input from the tractor. Another thing, MX7 spins blades a bit faster which might require a bit more input power.

2. 709 has a HD gearcase, 100 HP cont., 150 HP peak

I would buy 709 over MX7. I've run some Hawkline HD 7 footers, I was breaking bolts every time I used it. The one I used did not have chains so I almost broke a window on my shed, 100ft from where I was cutting ...

Get safety chains.

Peter

 

[dirtyj]

Thanks for the response guys.

I also found out the MX7 requires 40 hp input, not 50 - misprint from JD.

I should have the order in on the 709 today.

Thanks again.

 

[aczlan]

The MX series is showing some signs of giving problems. We sell the 7 ft Hawkline/International for $1995, This is a true HD cutter at a $1500 savings. I am not trying to sell you one, I can't ship it. Just showing you what a range of cutters are available. Ken Sweet

No shield on the slip clutch? That could hurt.

Aaron Z

 

[Gary Fowler]

In some instances I dont think the light, med or heavy duty rating can be assumed to mean higher rating for gear boxes. I have what I consider a light duty with 12 gauge metal deck 6 foot Howse 600 shredder and it has a 65 HP gear box (or 75 HP or 100 HP) depending on who you believe as listed on Tractorhouse. I have never really checked it to see what it specs out to but it handles all my 50 HP Yanmar will deliver.
From what I see, the heavy duty seems to just increase the deck metal thickness and add in more stiffeners which increases the price. The HP rating does not seem to change enough to be significant with duty rating. Size matters- which seems to be the significant factor in HP rating- the wider the higher gearbox rating you have to have, however the gearbox rating seems to be all over the spectrum with different manufacturers. So just beware of what the salesman tells you. I think I was told that mine was 65 HP but I see the same model advertised from 65-100.

 

[Gary Fowler]

From what I see in rotary cutter specs, it looks like light duty is 12 ga or about 1/8" for the deck metal thickness, jumps to approximately 3/16" for medium duty and 1/4" for heavy duty. Some have additional cross bracing for stiffeners in addition to the heavier sheet metal while other designs seem to have no additional stiffeners (at least on top)

 

[sweettractors]

In some instances I dont think the light, med or heavy duty rating can be assumed to mean higher rating for gear boxes. I have what I consider a light duty with 12 gauge metal deck 6 foot Howse 600 shredder and it has a 65 HP gear box (or 75 HP or 100 HP) depending on who you believe as listed on Tractorhouse. I have never really checked it to see what it specs out to but it handles all my 50 HP Yanmar will deliver.
From what I see, the heavy duty seems to just increase the deck metal thickness and add in more stiffeners which increases the price. The HP rating does not seem to change enough to be significant with duty rating. Size matters- which seems to be the significant factor in HP rating- the wider the higher gearbox rating you have to have, however the gearbox rating seems to be all over the spectrum with different manufacturers. So just beware of what the salesman tells you. I think I was told that mine was 65 HP but I see the same model advertised from 65-100.

You hit the nail, pretty much right on the head. If anyone needs to verify what hp box you have,A 40 HP box will have a 12 spline output shaft and a 60-75 box will have a 15 spline output shaft and a "diamond" bolt mount pattern. A diamond mount pattern means there is a bolt hole in the mount directly under the input shaft. Ken Sweet