Shear pin misery... only thing left is adding a slip clutch?

[airbiscuit]

Before you do anything, maybe you should see if your problem goes away simply by engaging the PTO at idle.

If not, you could drill a second shear pin hole that might be just enough to hold and still offer overload protection.

 

[CCWKen]

Better that the OP gets a slip clutch. He's engaging under power. Bigger shear pins will just move the shear point--To the tractor parts most likely.

If I were him, I'd keep PTO drive parts in stock.

 

[airbiscuit]

Better that the OP gets a slip clutch. He's engaging under power. Bigger shear pins will just move the shear point--To the tractor parts most likely.

If I were him, I'd keep PTO drive parts in stock.

Are you suggesting that he engage the PTO at full PTO RPMs? As I said, he may not keep breaking shear pins if he does more of a soft start (at idle).

If he goes to a slip clutch, he will also have to replace the PTO Shaft with one that doesn't have a shear pin.

 

[N80]

Are you suggesting that he engage the PTO at full PTO RPMs? As I said, he may not keep breaking shear pins if he does more of a soft start (at idle).

If he goes to a slip clutch, he will also have to replace the PTO Shaft with one that doesn't have a shear pin.

I think he is just saying that the OP is engaging the PTO at higher RPMs and has quoted his manual indicating that he should do so.

The bottom line is that the FIRST thing the OP needs to do is to engage the PTO at idle RPM and see what happens for a while as this is probably the entire problem.

Some say a slip clutch is not necessary on a belt driven device which makes sense so going to larger bolts or a slip clutch before learning to engage the implement properly is....inadvisable.

 

[airbiscuit]

The bottom line is that the FIRST thing the OP needs to do is to engage the PTO at idle RPM and see what happens for a while as this is probably the entire problem.

Some say a slip clutch is not necessary on a belt driven device which makes sense so going to larger bolts or a slip clutch before learning to engage the implement properly is....inadvisable.

I agree. Hopefully, engage PTO at idle and problem solved. No use chasing a solution in search of a problem.

 

[IslandTractor]

I do not bring it up from idle. That is not a feasible situation in my real world. I cannot idle down every time I want to begin mowing.

Why can't you idle down before engaging the mower? That's what all the rest of us with flail mowers do. You don't need to disengage the flail once you start it. Just raise it a bit if you want to stop cutting momentarily. Not sure what the Chinese flail manual says but it is simply nuts to engage any implement from a start while the engine is running at full PTO. Even a slip clutch isn't designed for that sort of abuse.

 

[Dadnatron]

Guys guys... I can engage at a lower RPM. I see your point. All I am saying is that according to the JD manual that comes with the machine, it says to throttle to PTO speed, then engage. I have an electric PTO clutch, and as soon as I engage it, the RPMs drop down. I don't think it is simply overcoming inertia via brute force (but I could be wrong). I think the tractor immediately throttles back then builds up. It happens when I have nothing on the shaft as well. I've just been doing what I grew up with and have always done and the manual corroborated my actions.

I did a very slow PTO engagement, and it worked, but it felt like I was going to break that pin the entire time. I just didn't have confidence that it would hold. After it began spinning, there wasn't an issue, but still in my head, I knew the shaft is undersized.

But... I am having a VERY hard time finding a long enough shaft to work. I did find one with a CV jnt and slip clutch... for $1070 + shipping. Probably $1200 to my door.... That's more than 50% of what I paid for the whole thing shipped to Cincinnati.

 

[TheMan419]

.

But... I am having a VERY hard time finding a long enough shaft to work. I did find one with a CV jnt and slip clutch... for $1070 + shipping. Probably $1200 to my door.... That's more than 50% of what I paid for the whole thing shipped to Cincinnati.

This is the cheap one you had shipped from China right? Part of the reason it was so cheap was that it shipped with a cheap PTO shaft.....

 

[IslandTractor]

Guys guys... I can engage at a lower RPM. I see your point. All I am saying is that according to the JD manual that comes with the machine, it says to throttle to PTO speed, then engage. I have an electric PTO clutch, and as soon as I engage it, the RPMs drop down. I don't think it is simply overcoming inertia via brute force (but I could be wrong). I think the tractor immediately throttles back then builds up. It happens when I have nothing on the shaft as well. I've just been doing what I grew up with and have always done and the manual corroborated my actions.

I did a very slow PTO engagement, and it worked, but it felt like I was going to break that pin the entire time. I just didn't have confidence that it would hold. After it began spinning, there wasn't an issue, but still in my head, I knew the shaft is undersized.

But... I am having a VERY hard time finding a long enough shaft to work. I did find one with a CV jnt and slip clutch... for $1070 + shipping. Probably $1200 to my door.... That's more than 50% of what I paid for the whole thing shipped to Cincinnati.

I also have electric PTO clutch on my Kioti DK40SE. I raise the rpm just a few hundred above idle when engaging the flail or any other implement. There is a jerk and engine speed drops a bit then comes right up again.

 

[ruffdog]

Years back when I was running equipment with a big flywheel, like a baler, you always be gentle and bring the rpm's up slow. Breaking the equipment on the one good day to get the hay in is not the way to make hay.