... Part 3 ...
I can report on good authority that the
duckfoot finish blades I mounted on my Caroni 1900 do chop the grass into small bits even cutting 3 inches high. These blades do not make hay.
The fastest I have mowed is 4th gear which is about 2.8 mph with the tractor at 2500 rpm and PTO at 540 rpm. I used this speed where the grass was not as thick. In 4th gear there seems to be a bit less chopped grass behind the mower than in 3rd gear. In other words less grass was cut in 4th gear than in 3rd gear. I conclude that the duckfoot blades create a strong
vacuum that lifts the grass before cutting it. Since that vacuum effect has more time to operate running at a slower speed, that explains why there is more chopped grass behind the mower when using 3rd gear than using 4th gear.
In 3rd gear (2500 tractor rpm, 540 PTO rpm) my tractor ground speed is rated at 1.85 mph. There was no problem mowing 3 ft tall grass (3 inch cutting height) that was planted last fall and not touched since. But note that I am mowing grass and weeds, not brush and rocks.
And although it is still early days for me with this mower, my sense is that in 3rd gear (instead of 4th) the mower does a better job of lifting and cutting the grass that was pressed down by the tractor tires.
Below are some observations on using both the duckfoot blades and OEM 'Y' blades. The mowing height was set to 3 inches while parked on a concrete slab. For the Y blades I measured 3 inches to the middle of the cutting edge.
1. There does not seem to be any difference in the general size of the chopped grass bits until getting into 3 foot tall grass. In that taller grass the Y blades *might* produce a finer chop. Even if true the difference is minor.
2. If I am mowing with the duckfoot blades and lift the mower with the 3-point without first lowering the rpm then the mower throws lots of grass bits all over the back of the tractor and all the way up to the front of the tractor. This tells me the blades are creating a vacuum effect (even mowing 3 inches high) and moving a ton of air. The Y blades do the same thing but not nearly as much.
3. With the PTO spinning at 540 rpm and the mower lowered to the ground, the 2 sets of blades make a different sound. The duckfoot blades are louder and sound like what I image a
26 hp vacuum cleaner would sound like. I wear ear protection.
4. In the following pic both cuts were made with the duckfoot blades. The cut on the right was made in 3rd gear and the one on the left in first gear. All my cutting is at 540 rpm.
The following pic is a closer view of the 1st gear cut.
And here is a closer view of the 3rd gear cut.
5. I put on the Y blades and cut a strip right next to each of the duckfoot strips in the above pics. In general 1st gear and 3rd gear results look similar since there is a fairly solid layer of chopped grass on top of all 4 strips. The next day I hand raked part of both areas. I raked in the same direction I mowed. For the 1st gear strips my raking produced about the same amount of grass for the 2 sets of blades. But for the 3rd gear strips the duckfoot blades made a noticeably bigger pile of raked up grass than the strip where I used the Y blades.
6. When mowing at a 3 inch height with the duckfoot blades the grass that the tractor tires drove over was not cut as short as the grass that was not driven over. Below is a pic taken a couple of days after I mowed. The grass in this area was about a foot high. The green strips are grass that was driven on. Note that most of the area in the pic was mowed in 4th gear. I still need to experiment with a lower mowing height.
7. The different types of blades will show different results in different types of grass. We have an area in our pasture where the grass is more blade than stem. I used both sets of blades on that area and the duckfoot blades did a much better job.
8. I mowed a pasture for a neighbor using the OEM Y blades. That area included a patch of 7 foot tall reed canary grass. I went through that area in 1st gear and did OK. None of the grade 2 clevis pins failed.
And finally, here is a pic of what I have been using to mow our pasture.
Some of you will no doubt recognize the above machine as made by Bachtold Engineering formerly of Forrest, IL. Pity that company is long gone since this is one of the best pieces of small engine gear I ever bought. Actually I will still be using this self-propelled walk-behind mower for the first cutting each year. When it is time to start mowing much of the pasture area is still too soft from the Pacific Northwest monsoons to support 5,000+ pounds of tractor, FEL and mower.
Good luck with it.
