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.

 

[john_bud]

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.

Well GOOD!

If you are up to the task of diddling around with the slip clutch you can quit buying bolts in bulk! You have shown a lot of folks that you do indeed need to keep on top of the slip clutch to keep it slipping. Now that it is free, it is easier to keep free and takes less abuse to loosen it up. But be warned, they rust up hard even in a shed!

Oh, the moderators here are very good at keeping us all on the straight and narrow, but the group is 99.9% mellow and helpful by nature anyway. Still, it's good to hear that the advice you got here was accurate, helpful and more importantly solved your problem. I'm sure the givers of advice appreciate it!

 

[Bedlam]

Just curious if anyone has had to replace the friction discs in these clutches. From normal wear or over spinning. And what the cost was to replace them Thanks.

 

[greg_g]

I've had one permanently mounted on my 6' rotary cutter for >4 years now, it's still good as new. But that's cuz I clean and readjust it no less than once a year. There are two friction plates by the way, if one's shot - the other one's probably in bad shape too.

But there's no way to even guess where to go for parts, without knowing manufacturer/make/model of your specific clutch.

//greg//

 

[em14]

The cost of the clutch fiber disc depends on the “manufacturer/reseller”of the unit ... at least that has been my experience ... many of these are interchangeable and it is worth asking around … Example: I needed 4 fiber disc for a 10 ft Howse and had to use a sub from a none Howse and ended up paying about double the price Howse charges … there are only a few manufacturers of the PTO units in the world or so I have been told … the last set of 4 disc I bought for this cutter was form Howse and was less than $20.00!
Leo

 

[Bedlam]

Thanks or the reply, I just wondered if the disc replacement cost would be not worth it as a new clutch only cost 90 some odd dollars. but 20 dollars even with shipping sounds better that the whole clutch thanks.
Al

 

[IslandTractor]

I'm kinda surprised some of you are wearing out the friction plates on these slip clutches. I'd think that they "slip" only as often as a shear pin would break and therefore they would basically never wear out (except maybe in constant commercial use). If they do wear out, isn't that an indication that they are slipping too much and therefore not properly adjusted/maintained?

 

[greg_g]

If they do wear out, isn't that an indication that they are slipping too much and therefore not properly adjusted/maintained?

Concur. I like having a well stocked spares shelf. But knowing the expected longevity of a properly maintained slipclutch, I have never bothered buying up any spares.

That said, I guess the springs could rust and weaken over time. I might buy a set of them to have on hand.

//greg//

 

[Bedlam]

This site sells the clutch and also say great to use with a shear pin also. I'm sure they say it because they want a sale.
PTO Slip Clutch Sale
So I guess its all a mater of opinion. Apparently one or the other or both it wont tear up the drive train.
personally id like to know if the slip clutch failed, that the shear bolt would had some protection also.Judging by the tendency for the slip to become not to slipping due to care.

 

[gemini5362]

One of the recurring topics in this post is the clutch rusting and having to be freed up so that it will work. It seems to me if that is a possibility of happening you could be in a situation where you hit something immovable. If your clutch is frozen together your gear box is going to take all of the shock from the impact. I would think that the shear pin would be a good idea just as a backup in case that happens. I also dont see what is wrong with having the shear pin. They are a lot cheaper than gear boxes and definetly easier to replace.

 

[greg_g]

This site sells the clutch and also say great to use with a shear pin also.

I don't read it that way. When I see "[FONT=Arial, Helvetica, sans-serif]Ideal for adding a slip clutch to machines that have shear pin protection", I think "ideal replacement for shear pin drivelines". Shear pin protection is used when smooth bore fittings are mated. So when the implementtransmission input shaft is smooth - a smoothbore slip clutch must be used.

In my experience, factory slip clutch protected PTO drivelines mate to splined implement transmission input shafts. Spline to spline connections render any discussion of shear bolt moot. All that's required is a fastener bolt.

Your point doesn become valid however - for the owner who wants to upgrade his smoothbore shear bolt protection to slip clutch but DOESN'T believe in preventative maintenance

//greg//
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