Plow Shear Bolts are shearing on new tractor

[AmericanTractorDriver]

Hello,

Last year we used a 25-hp gas tractor with water-filled tires to plow virgin ground for our garden. Using a 1-bottom Leinbach Line plow, we didn't snap a single shear bolt.

This year, we're using a 40-hp diesel John Deere 2040, also with water-filled tires, to plow the same ground that's been plowed and tilled during 2014.

This year, I seem to break a 7/16 grade 2 shear bolt on every row through the garden. I know there's a lot of drag on the plow because I hardly have enough traction, even with the differential lock on and aggressive field tires.

Could I be getting the plow too deep with the 2040? seems like as long as it's not buried below the top of the mold-board, deeper would be better.

What am I missing?

Thanks!

 

[DJ54]

Plowing depth should be 1/2 the width of the plow share, as a general rule..

 

[AmericanTractorDriver]

In other words if the cutting knife on the bottom is 12", plow depth should be around 6"?

 

[Big Barn]

Depending on your soil type it may not be beneficial to be plowing too deep. ie: bringing up clay or virgin peat. Our M F 3x16" bottom reversible plow used 5/16 grade 5 shear bolts. You could try upgrading to a grade 5 bolt. Terry
The 'cutting knife' on the bottom is the plow share and is not representative of your width of cut.

 

[mkreitler]

Like DJ54 said in his reply you need to only go half of what your plow shear is as far as depth say the shear is 12"long go 6" deep if it is 14"long go 7. I myself shoot for 6 to 8 in. As for shear bolts go with a GRADE 5. It sounds to me that you are going to deep, as for H.P.the 2040 with 40 should have no problem pulling one plow.I pulled 3- 14" with a 3600 FORD that is about the same size as the 2040 in corn ground at 8"deep all day long in 3rd gear.Also make sure you have everything set correctly as for as the plow goes it DOES MAKE A DIFFERANCE as to how hard it may pull....

 

[jeff9366]

Seems like as long as the plows is not buried below the top of the mold-board, deeper would be better.

Nah, moldboard plows are pretty inflexible.

12" plow will turn soil properly only in range of 5" to 7".

14" plow will turn soil properly only in range of 6" to 8" etc.


A moldboard plow should turn soil out of the furrow so weed roots from the furrow soil are up in the air to dry, die and decompose.

If deep is your objective, get a subsoiler.


(Same plow both years?)

 

[jeff9366]

In other words if the cutting knife on the bottom is 12", plow depth should be around 6"?

The cutting knife is called the SHARE.

Look at the shape of the moldboard. As the plow goes deeper, soil resistance (called DRAFT FORCE) increases very rapidly, not proportionally.

 

[jeff9366]

Depending on your soil type it may not be beneficial to be plowing too deep. ie: bringing up clay or virgin peat. Our M F 3x16" bottom reversible plow used 5/16 grade 5 shear bolts. You could try upgrading to a grade 5 bolt.

Careful with higher tensile shear bolts. Most small tractors do not have Draft Control. Without Draft Control, should the plow hit an immovable object in the soil, there is the potential for the tractor to go VERTICAL, pivoting around the rear axle, in 1/2 second.

 

[Agvg]

Is this a real tractor? JD 2040 seems to be a std agricultural tractor so it should have draft control, or are there a newer series with same number?

 

[pmsmechanic]

Careful with higher tensile shear bolts. Most small tractors do not have Draft Control. Without Draft Control, should the plow hit an immovable object in the soil, there is the potential for the tractor to go VERTICAL, pivoting around the rear axle, in 1/2 second.

Ok so this is true if you are pulling a semi mount plow. If the plow is mounted on the three point hitch it will go no higher that the three point will allow it to.