Help with shear pin info

houstonscott · May 4, 2011

New here, broke a shear pin on a Howse 6' HD mower. It's just a steal bolt type of pin. Need to know what grade it is and how long. It appears to be 1/2" stuff. Can't find it anywhere. Help. Oh didn't run over anything I think I just engaged the PTO a little over idle and it broke or I may have throttled up a bit to fast and it broke.

HS

sweettractors · May 4, 2011

I think most shearpins for brush hogs are Grade 2 and 1/2 X 3 1/2. Check your owners manual or call Howse to be sure. Ken Sweet

BATTY54 · May 4, 2011

I have run my Howse mower for years with grade 5 (3 marks) bolts as shear pins. I make sure the unthreaded shank portion of the bolt is long enough to go through the yoke.

Car Doc · May 4, 2011

I have replaced shear bolts in my rough cut also only occasionally though and grade 2 bolts are tough to find and is what I believe is spec on them.

I have a grade 5 in mine and haven't replaced it since but I am careful when driving over saplings etc.

I have seen grade 2 bolts at the farm store you have to look to find a bolt with no markings thats a grade 2.

clemsonfor · May 4, 2011

I think the rule is like grade 2 for less than 40 hp and over that use a grade 5.

houstonscott · May 4, 2011

Great info, got to love TBN. The tractor has 57hp and maybe why I broke it so easy. Looks like I should buy half a dozen when I find them. Thanks..

HS

Mistyridgefarm · May 4, 2011

With that kind of horsepower I recommend upgrading to a slip clutch. I think you have more torque from the tractor and a fair amount of centrifical force from the 6 cutter. I have a slip on the cutter but have had shear bolts on a few other implements and use grade 5 except for an old single bottom moldboard. It prefers the lower grade, although a punch is needed to get the broken softies out.

houstonscott · May 5, 2011

Found everything I need here.

Bolt Depot - Nuts and Bolts, Screws and Fasteners online

HS

Soundguy · May 5, 2011

houstonscott said:
New here, broke a shear pin on a Howse 6' HD mower. It's just a steal bolt type of pin. Need to know what grade it is and how long. It appears to be 1/2" stuff. Can't find it anywhere. Help. Oh didn't run over anything I think I just engaged the PTO a little over idle and it broke or I may have throttled up a bit to fast and it broke.

HS

check your manual.. it's in there. my howse manual lists mine.. and howse manuals are downloadable.

IMHO.. I'd go grade 2 for gearbox and pto clutch safety.

soundguy