Newbie shear pin question

[viceprincipal]

My first run with my new Landpride tiller last all of 20 feet, before it found a big chunk of wood and broke my shear pin. Are shear pins an item you go to the dealer for or do you just buy the right size bolt in a specific grade (my TBN search found a thread where grade 8.8 was mentioned?) Thanks in advance!
Geoff

 

[greg_g]

You didn't specify which tiller, so - based upon your tractor and no slip clutch - I'll assume the RTR series. The maintenance section of that owners manual says:
Shear Bolt and Lock Nut Part Numbers
Part No. Part Description
RTR05
165.000.509 BOLT & NUT M6X40 CL 8.8
(Torque nut to 8 ft. lbs.)
Note: If M6 bolt shears excessively, a 1/4”-20 GR5 bolt & nut
may be used. A 1/4” -20 GR8 bolt is not recommended as it may
cause damage to profiles, tiller frame and/or components

//greg//

 

[Combustix]

Geoff I would look into getting a slip clutch. Have one on my Ortolan and it has saved me a couple times.

 

[Soundguy]

keep in mind that 8.8 # is not meaning grade 8.

most shear pins are gr2 ( no hash marks ).. it looks liek the manual is oking UP TO a gr5 ( 3 hash marks ) if a gr2 shears often.

and yes.. unless a specialized pual diameter pin or headless pin.. a gr2 bolt is the usual shear protection of choice..

soundguy

 

[viceprincipal]

Thanks for all the info! I just needed to know if I had to hit the dealership or the hardware store on the way home...

This site is great.. I had never even really ridden a tractor before buying my BX2660 this summer after getting an acreage. The amount of information I've gotten from this site has been staggering. The only complaint is my wish list keeps growing after seeing everything here!!

Geoff

 

[Soundguy]

it's a disease.. and pretty much gets worse.. you start with a single tractor and maybee an implement or two.. then it takes hold.. and eventually you are left with something like this ( and this anit near all of them either. i got 2 more sheds full...) :

 

[Baby Grand]

it's a disease.. and pretty much gets worse.. you start with a single tractor and maybee an implement or two.. then it takes hold.. and eventually you are left with something like this ( and this anit near all of them either. i got 2 more sheds full...) :

I've had the bug for 4 years and it's only getting worse/better.

Geoff - I highly recommend the slip clutch, too. You have to diddle with it periodically to keep it adjusted, but you get to choose when you diddle. With the shear pin, odds are you will find yourself in a half tilled plot diddling with a shear pin and maybe remembering that that's what you forgot to buy more of the last time you went into town.

If you continue with the shear bolt, make sure that you get a bolt with a smooth shank through the holes in the shaft to be protected and just a little thread on the end to secure the bolt with a nut. You don't want to rely on the threaded section for shear protection. Something like these:

-Jim

 

[oldnslo]

keep in mind that 8.8 # is not meaning grade 8.

most shear pins are gr2 ( no hash marks ).. it looks liek the manual is oking UP TO a gr5 ( 3 hash marks ) if a gr2 shears often.

and yes.. unless a specialized pual diameter pin or headless pin.. a gr2 bolt is the usual shear protection of choice..

soundguy

Metric grade of 8.8 is the equivalent of american grade 5.

10.9 is the equivalent of grade 8.

Roy

 

[JoeL4330]

If you continue with the shear bolt, make sure that you get a bolt with a smooth shank through the holes in the shaft to be protected and just a little thread on the end to secure the bolt with a nut. You don't want to rely on the threaded section for shear protection. Something like these:
View attachment 232414
-Jim

Agree that the spec involves the smooth shank portion and not the threaded part (which is variably weaker); but, the manual quoted referred to a torque spec so the smooth shaft segment wants to be the right length...but I wouldn't worry about it and note that the (slightly) higher-strength 1/4-20 would probably be fully threaded (and easier and cheaper to find). All that said, slip clutch seems best (and, still requires the shear pin in place, no?)

 

[DennisFolsom]

it's a disease.. and pretty much gets worse.. you start with a single tractor and maybee an implement or two.. then it takes hold.. and eventually you are left with something like this ( and this anit near all of them either. i got 2 more sheds full...) :

Nice tractor collection!:thumbsup: