I'm in shear pin purgatory! Please help

[Rara Avis]

I don't see that statement as indicating you should not use both shear pin and slip clutch but rather as a manufacturer's instructions intended to cover models that have one or the other. Some models are identical except for slip clutch vs lower priced shear pin. Clearly you need either one or the other but what is the downside of having (in theory) a primary slip clutch, well adjusted and maintained of course, and a backup shear pin for when the slip clutch rusts or is badly adusted? How could the two protection devices interfer with each other?

Why pay for two systems, when you only need one...
(Sort of like wearing a belt and suspenders)

The LandPride manuals NEVER say AND but only EITHER/OR...

If you want, contact LandPride and get back to us with their response...

 

[MikeD74T]

Driveline Protection
! CAUTION
Engage parking brake, disengage PTO, shut off tractor, and
remove key before making any of the following adjustments.
Cutter drive components are protected from shock loads
by either a two plate friction clutch or a shear bolt. Avoid
shear bolt failure by engaging the PTO slowly at low
engine rpm. See your Land Pride Dealer when replacing
shear bolts.

The above is right out of the LANDPRIDE ROTARY CUTTER OPERATOR MANUAL...
Land Pride Single Deck Rotary Cutters

Quotes can be misinterpreted. From their online operating & parts manuals, only the 15 series, the smallest Landpride rotary cutters, are availible with either a shear pin or slip clutch. The rest are all clutch. All clutch models, including the 15 series, have a splined gearbox input shaft. The 15 series is also availible with a smooth input shaft drilled for a shear pin, listed a grade 2 half inch bolt. I believe the above quote is a statement of their design criteria not an operating limitation/recommendation.

My cutter has a smooth input shaft with a shear pin which I precede with a tractor shaft mounted slip clutch. MikeD74T

 

[Rara Avis]

Quotes can be misinterpreted. From their online operating & parts manuals, only the 15 series, the smallest Landpride rotary cutters, are availible with either a shear pin or slip clutch. The rest are all clutch. All clutch models, including the 15 series, have a splined gearbox input shaft. The 15 series is also availible with a smooth input shaft drilled for a shear pin, listed a grade 2 half inch bolt. I believe the above quote is a statement of their design criteria not an operating limitation/recommendation.

My cutter has a smooth input shaft with a shear pin which I precede with a tractor shaft mounted slip clutch. MikeD74T

Well, then if the O.P. has a larger LandPride...HE DEFINITELY should NOT be using SHEAR PINS...

 

[MikeD74T]

Well, then if the O.P. has a larger LandPride...HE DEFINITELY should NOT be using SHEAR PINS...

Guess the O.P. wouldn't as there's no place on the larger Landpride drivelines to put one.
I'm just used to having a backup plan. In nuclear power it's common to have multiple levels of protection. All important motors have fuses before breakers. Breakers are convenient but fuses will always open.
I'm at work, what's your excuse for being awake at this hour? MikeD74T

 

[IslandTractor]

I'm at work, what's your excuse for being awake at this hour? MikeD74T

Jet lag.

 

[Jim_Fisher]

Yep, been reading the manual today. All 4 of those bolts are almost all the way out, there is gap between the bolt and the plate, and yet it doesn't slip.

The plates looks rusty, maybe its been on the dealers lot for a year or so?

jinjimbob,

Your description sounds like a Walterscheid slip clutch. The tension is provided by a spring steel plate inside the clutch.

To disengage the clutch, tighten all four nuts. To engage the clutch, loosen the nuts, leaving a gap. The ends of the studs are staked to prevent the nuts from falling off.

Walterscheid has an on-line technical manual in German and English http://www.walterscheid.com/artikel/download/Service/GKN-Walterscheid-technisches-Handbuch.pdf

The pdf is huge and takes several minutes to download over dsl. See page 94 for a picture of a Walterscheid slip clutch.

 

[N80]

The slipclutch on my JD mower uses a single plate-like spring called a Belleville spring.

Part 'F' is the Belleville spring. Pretty simple.

As to using a slip clutch AND a shear bolt, well, what is the downside? Granted, it may be overkill, but what's the point of arguing or quoteing owner's manuals? Expense isn't the issue. How much does a Chinese grade 2 bolt cost? And hey, the proof is in the pudding. The OP has a slip clutch and shear bolts.....and it sounds like its a darn good thing he had both!

 

[Laminarman]

Loosened her up again, reved her up, mowed a little and I think that's what it took. After scribing a line yet again and this time loosening all the bolts even more, I had "the moment". I tried to mow a small but high patch of field behind my house and all of a sudden she bogged down, BANG! and whirring, no blade turn, no broken shear bolt. All the plates moved and at that point I knew the slip clutch was slipping. An epiphany and I learned a lesson. She made some good smells as she burned off the oxidation for a few seconds, and then I tightened all things up. I appreciate all the help here.

I belong to boards or forums for astronomy, photography, Porsche's, Labrador Retrievers, hunting, fishing and wine. But this board takes the cake. I ALWAYS get answers fast, with courtesy and accuracy. I do appreciate this site so much and it is simply the most pleasurable to use, a GREAT community.

 

[Rara Avis]

Guess the O.P. wouldn't as there's no place on the larger Landpride drivelines to put one.
I'm just used to having a backup plan. In nuclear power it's common to have multiple levels of protection. All important motors have fuses before breakers. Breakers are convenient but fuses will always open.
I'm at work, what's your excuse for being awake at this hour? MikeD74T

So you work a Seabrook...

 

[jinjimbob]

jinjimbob,

Your description sounds like a Walterscheid slip clutch. The tension is provided by a spring steel plate inside the clutch.

To disengage the clutch, tighten all four nuts. To engage the clutch, loosen the nuts, leaving a gap. The ends of the studs are staked to prevent the nuts from falling off.

Walterscheid has an on-line technical manual in German and English http://www.walterscheid.com/artikel/download/Service/GKN-Walterscheid-technisches-Handbuch.pdf

The pdf is huge and takes several minutes to download over dsl. See page 94 for a picture of a Walterscheid slip clutch.

Thanks ever so much for this, your are correct. The version of tiller I have must be from before '07, looks they changed the design on the slip clutches on the newer models. It was made in Germany too.