Downside to disc harrow being narrower than tractor tread width?

[npalen]

Welcome to TBN

I might try the 4ft one. If there is a problem, paint it and sell it for 20% more than you paid.



What's the weight on the 4ft one? A photo would help. I've seen some so light that they just bounced over everything, unless it was already loose. Just a cultivator, not for breaking up ground.

Bruce

Weight per blade makes for a good comparison between disc harrows.

 

[npalen]

Every light Disc Harrow I have seen has scalloped pans. Scalloped pans cut/penetrate hard ground much better than smooth pans but are intrinsically weaker than smooth pans, therefore potentially subject to rock damage. Smooth pans do not penetrate well until they are 22" or more in diameter, which is much too much Disc Harrow for your L2501.



I turned about 1 acre with a box blade last year. I kicked up a lot of rocks from about 6” to 12” in size (and some even larger).

The widest pan spacing you can get on a Disc Harrow your tractor can manage is 9", measured with the gang angles flat. When the gangs are angled, as they must be for the pans to penetrate, channel between the pans may be only 5".
(( Adjustability varies moderately between Disc Harrow brands. ))


MORE: Remove rocks from soil field site:tractorbynet.com

The widest pan spacing you can get on a Disc Harrow your tractor can manage is 9", measured with the gang angles flat. When the gangs are angled, as they must be for the pans to penetrate, channel between the pans may be only 5".

Twenty degrees is a fairly steep angle for disc gangs and a 9" spacing between blades would result in about 8.5" actual cutting width.

Smooth pans do not penetrate well until they are 22" or more in diameter, which is much too much Disc Harrow for your L2501.

For a given implement weight, smaller diameter blades will penetrate better than larger diameter. Think of the blade as a wheel, a smaller wheel tends to sink where a larger wheel tends to float. It takes more weight to make the larger blades penetrate especially in firm soil.

 

[jeff9366]

MORE VIDEOS: https://www.youtube.com/results?search_query=compact+tractor+rock+stone+picker

 

[Egon]

Heavy soil, lots of rocks, 25 HP. ??
It’s gonna be hard to pull a disk that will do any good. Plow with trips or a chisel type cultivator would probably be better choices. A rock picker would surely help.

 

[jeff9366]

For a given implement weight, smaller diameter blades will penetrate better than larger diameter. Think of the blade as a wheel, a smaller wheel tends to sink where a larger wheel tends to float. It takes more weight to make the larger blades penetrate especially in firm soil.

True, in theory. But box frame disc harrows increase in weight with larger diameter pans.

The most common thickness of 18" pans is 3.0mm, though 4.0mm are not uncommon.

The most common thickness of 20" pans is 4.5mm, though 5.0 and 6mm are not uncommon.

Not only are 20" diameter pans larger, but they are usually thicker.

In my experience the heavier pan always penetrates/cuts better.

 

[npalen]

True, in theory. But box frame disc harrows increase in weight with larger diameter pans.

The most common thickness of 18" pans is 3.0mm, though 4.0mm are not uncommon.

The most common thickness of 20" pans is 4.5mm, though 5.0 and 6mm are not uncommon.

Not only are 20" diameter pans larger, but they are usually thicker.

In my experience the heavier pan always penetrates/cuts better.

We are basically saying the same thing: It takes more weight to make large diameter blades cut and, yes, more horsepower. A smaller diameter blade will cut with less weight (per blade) and less horsepower. There is a reason they don't put 24" diameter blades on a 5' disc harrow nor 18" blades on a 50 ft five section disc.
There are a number of other factors that affect disc blade penetration such as concavity, thickness and edge sharpness.

 

[oosik]

Disk is narrower than your back wheel width. Use your stabilizers to offset and cover one back wheel track. Done correctly - you can disk an entire field and only have one wheel track.