Shear pin on a Bush Hog..

[kide]

OK all you grew up in the country types..
I'm using the neighbors JD 2355 to bushhog their fields (they've retired, sold off the herd and the fields are starting to get a little brushy around the edges). We hooked up the JD Woods (or Woods type) Bushhog today and even before I started, I sheared the drive pin on the PTO input. I had been told that this was just a grade three bolt (5/16ths), but when I went down to my shop, all the cheesy grade three bolts had too big a shoulder to fit through. I dug around and came up with some of the grade 5 bolts from TSC that are a dark green/olive color, with a shoulder the same OD as the threads, which worked fine - except - I sheared another two of these before learning to eaaaase the clutch out (Hmmmm - sounds like another thread about PTO clutches...). I wasn't dumping the clutch (two stage on a 2355, PTO engages from bottom to middle of range, transmission engages from middle to all the way out), and it could be grabby, but here's the question - what is the normal bolt/pin to be used for the shear pin - grade 5 or ?? I really hesitated to put a grade 8 in, that just puts the stress elsewhere, like on the PTO shaft on the 2355.....
Note - my range of experience on farm tractors has been limited to this one and a bunch of 2N, 9N and 8Ns when I was a kid......(and I've only lived next to these kind folks for about 35 years, so I want to make a good impression on 'em)

 

[lbuttke]

Kendell

From what my local hardware man told me the other day when I went to get a shear bolt for my hay bailer is a soft #3 bolt will not shear as cleanly as a regular shear bolt.
Has something to do with the #3 being soft and the metal streches during the shearing process instead of shearing quickly and clean.
My father used to just use #3 5/16 bolts as shear bolts and we always had to use a punch to clear the hole of the sheared bolt.

I would have to guess that there is something binding in the bushhog to cause the bolts to shear.
Could be a bad bearing, worn worm gear, a number of different things other than letting the clutch out to fast.

If you have not already done so, check to make suer everything is turning freely befor hooking the PTO shaft back up to the tractor.

 

[dross]

Kendell, We used grade 3. I googled a 2355 just for kicks and what I found said it had 56 hp. You didn't say how big the bushhog was but if it's only 5 or 6 ft. rated for 30-40 hp it just makes the shear pin problem worse. Did you check the gear box grease? Woods might have gotten fancy at some point and built a "woods only" shear pin. Sounds like you got it under control, slow and steady.

 

[kide]

The deck turns freely, but there is a ton of inertia in that big blade (6 foot deck). Lonny - what you say about the shearing rings true - all three of the grade 5 bolts sheared clean with no smearing - I'll go buy a few more for them. Part of the issue here is that they've never used it too much, so they've got as many questions as answers. Once running, I never sheared a bolt yesterday, even when I dropped the deck all the way down.... it was always when engaging the clutch. Off to do another 20 acres !!!

 

[bbowman]

Kendell;

Lot of us redneck,country-boy,wannabees use them thar' grade 5's!
Bobby B.

 

[kide]

Bobby:
Now would that be rednecks from <u>Down</u> South?? ("Up South" just hurts my ears...)You did notice I called it the proper "Bush" Hog, not a "Brush" Hog, didn't cha???

BTW - 7 hours of seat time on the 2355 today, never sheared a pin - obviously the problem was operator error....

 

[bbowman]

Kendell;

Y'all got the spellin' down fair to middlin',but'cha work on yer nunciation.
Ya' gotta' drag out that there "haawg"! LOL!
Bobby B.

 

[dfrisk]

KENDELL - Dad had a Brillion 6 ft rotary cutter that followed Me around a LOT when He was farming. Mostly used it on the Super H which worked fine, I'd shear the pair of 5/16" bolts occasionally but only when You'd expect due to hitting something. We used grd 2 & 3, but never 5. Last year Dad farmed I was doing something for the neighbor and Dad put the 4010 on the cutter, round numbers THREE times the HP. Even at idle the PTO would shear those bolts if You weren't careful. Anyhow, somehow some grd 8 bolts ended up in the cutter. Dad's going along in about 5th gear, 6 mph in weeds/grass about hood high and the tractor isn't even pulling even a little bit. He looks back and sees that all He's doing is knocking the weeds down for the last 40-50 feet. He stops, backs up, gets off and picks the whole cutter blade assembly up and tosses it on the top of the cutter, the shaft had sheared off flush with the grease seal on the bottom of the gear case.

That's the problem when You try to do anything with a jd...spend most of your time wrenching on it or the implement!

 

[kide]

Dennis:
Well, after the initial pin shearing episode, I spent around 14 hours "bushawwwwging" and never sheared another one. This uses a single pin and it shears as clean as anything I've ever seen. I'm still bummed about the shoulder issue on the grade three bolts - I buy hardware in bulk from TSC and while it's not unusual to see random thickness on washers, it usually works for my projects. In this case, the shoulder is an interference fit on the hole in the shear pin flange on the PTO shaft. My original post on this was when I got to wondering if JD used a special OD pin.... and the mower has all SAE bolts on it, unlike the tractor.

One more complaint about JDs while we're at it (besides the mixture of metric and SAE on the tractor) and that's the design of the PTO engagement and its placement - it's a short lever down by your left foot, my old back complains every time I have to use that lever.. (according to tractordata.com this was built in Wesbaden, Germany - explains the metric..)

 

[bbowman]

Kendell;

Now you got it! We'll make a redneck out of you yet!
Bobby B.

!