[AT] Adventures with shear pins

Mon Jul 28 12:33:46 PDT 2014

I don't have much of a shear pin story to tell.  I've got a Ford 1520,
which is a 23-HP machine from the early 1990's, Japanese built (Shibaura).
 I don't own a brush cutter but I have two I can borrow from neighbors.
 One is a Bush Hog Squealer, the other is a Woods.  They are both 6' and
both rated for well over 23HP.  They both have slip clutches that I've
never seen come in to play.  What tends to happen when I start mowing rocks
or like yesterday, a big old hunk of carpet, is that my tractor just
stalls.  It is pretty benign.

SO

On Sun, Jul 27, 2014 at 9:40 PM, Dean VP <deanvp at att.net> wrote:

> I know about hitting things I wish I hadn't.  I have about a 3 acre pasture
> intended for horses.  After purcasing the place I wanted to get the pasture
> grass and weeds down to where it was manageable.  I walked the whole
> acreage
> policing for whatever.  Didn't find much other than some rocks that were
> larger than I thought appropriate. But nothing I thought would damage the
> pristine but used JD brush cutter.  So the field is now safe!  Of course my
> first pass was the three board fence line.  I didn't make 100' and there
> was
> a terrible racket under the brush cutter and a ungodly crease all 360
> degrees around the top of the deck. Man I was PO instantly.  My like new
> brysh cutter was spoiled.  I had failed to police right next to the fence.
> The PO had built the three board fence with 4x4 treated fence posts. Then
> installed the boards following the terrain and then cut off the 4x4 post
> tops that were not even with the top board with a chain saw at an angle to
> shed the rain and left the cutoffs where ever they fell.  The short pieces
> of 4x4 wedged between the blades and the deck and made an unmitigated mess.
> I was more than a little upset with my self for not doing a better policing
> job.  The damage was done and no way to undo it.  So I went from a pristine
> brush cutter to a damaged one in just a few seconds.  Stuff happens! But I
> didn't shear a pin. In fact I don't even know where it is.
> Connected by DROID on Verizon Wireless
>
> -----Original message-----
> From: Dean Vinson <dean at vinsonfarm.net>
> To: 'Antique tractor email discussion group' <at at lists.antique-tractor.com
> >
> Sent: Mon, Jul 28, 2014 00:53:12 GMT+00:00
> Subject: Re: [AT] Adventures with shear pins
>
> Hi Dean.   No, this rotary cutter doesn't have a slip clutch--just the
> shear
> bolt, which according to the operator's manual has to be grade 2 (since
> there's no slip clutch, I presume).   The assembly instructions at the back
> of the manual show both the shear bolt driveline (i.e., standard
> square-tube
> telescoping driveline with U joints, all encased in a free-rotating plastic
> safety shield, with a shear bolt connection at the input shaft to the
> gearbox on the mower deck) or the slip clutch driveline (slip clutch at the
> final U joint, just in front of the input shaft to the gearbox).   I assume
> the original owner bought it that way.  It's a pretty lightweight mower,
> and
> yes, the 620 is a little too much tractor for it.    I'd like a heavier and
> somewhat wider mower (this one is only a six foot cut, not quite enough to
> cleanly pick up the wheel tracks), so that's on the shopping list for
> someday.   For now, it works well enough and the only times I've broken the
> shear pin were when I hit something I wouldn't have wanted to hit if I'd
> known it was there.
>
> Dean Vinson
> Saint Paris, Ohio
>
>
> -----Original Message-----
> From: at-bounces at lists.antique-tractor.com
> [mailto:at-bounces at lists.antique-tractor.com] On Behalf Of Dean VP
> Sent: Thursday, July 24, 2014 11:06 PM
> To: 'Antique tractor email discussion group'
> Subject: Re: [AT] Adventures with shear pins
>
> Dean,
>
> But I'm not powering the brush cutter with a JD 620 with nearly 50HP
> either.
> My little JD 750 at best puts out 20HP to the PTO.  The JD 620 might be a
> little more tractor than what the brush cutter was designed to handle.
>
> Dean VP
> Snohomish, WA
>
> They say necessity is the mother of invention.
> Don't know who the father is, probably remorse.
> Red Green
>
> -----Original Message-----
> From: at-bounces at lists.antique-tractor.com
> [mailto:at-bounces at lists.antique-tractor.com] On Behalf Of Dean VP
> Sent: Thursday, July 24, 2014 7:43 PM
> To: 'Antique tractor email discussion group'
> Subject: Re: [AT] Adventures with shear pins
>
> Dean,
>
> Doesn't the brush hog have a slip clutch?  If it does it isn't doing its
> job. May be frozen due to age and the elements.  A shear pin isn't
> necessarily just a grade 5 bolt.  May require something harder.
> Check the Owner's Manual of the Brush Hog for the right pin. You probably
> have already done that.
> Don't want the wrong pin in there and then not do the job it is supposed
> to.
> I've owned a Brush cutter for over 10 years and have never sheared a pin
> and
> I've gotten into some really nasty stuff
> with it.   But I won't mention the name of manufacturer of it!  :-)
>
> Dean VP
> Snohomish, WA
>
> They say necessity is the mother of invention.
> Don't know who the father is, probably remorse.
> Red Green
>
> -----Original Message-----
> From: at-bounces at lists.antique-tractor.com
> [mailto:at-bounces at lists.antique-tractor.com] On Behalf Of Dean Vinson
> Sent: Thursday, July 24, 2014 7:20 PM
> To: 'Antique tractor email discussion group'
> Subject: [AT] Adventures with shear pins
>
> I've given up brush hogging the scruffier areas of my new place until the
> summer growth dies down and I can do more effective walk-throughs.   Lots
> of
> hard old osage orange branches laying low in the grass, along with
> occasional bits of nasty junk like cinder blocks and old rusty tangles of
> woven-wire fence sections.   I've replaced the shear bolt on the mower
> quite
> a few times, and had to have somebody out to fix a flat rear tire on the
> 620
> after a heavy piece of wire--possibly from that mass of old fence
> wire--punctured it.   Time to stop beating up the equipment and wait until
> I
> can really clear all the obstructions out.
>
> But the weather was spectacularly nice this evening, so after finishing up
> another chore I hooked the 620 back up to the mower and went out to the
> meadow by the orchard.   It had all been mowed last fall when I first
> visited this place and I walked around it several times back then, all very
> nice and trimmed, almost yard-like, so I was confident I wouldn't hit
> anything.    Spun up the brush hog, eased the clutch forward, and off I
> went...and then not two minutes later heard the mower suddenly hit
> something, followed by the "pop" of the shear bolt breaking and the sound
> of
> the mower coasting down, no longer being driven by the PTO.   #*^@! it,
> what
> the heck was down there?
>
> Turned out to be about 150 feet of very nice rubber garden hose, loosely
> coiled up in big easy ovals and spread over an area about four feet wide
> and
> eight feet long.   Still had water in it, or at least it did before that
> mower chopped it into about 20 pieces.   I hope the previous owner doesn't
> want it back...
>
> Dean Vinson
> Saint Paris, Ohio
>
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