[AT] McCormick plow

Dean VP deanvp at att.net
Thu Aug 21 10:36:10 PDT 2014


Charlie,

All the forces have to come out equal. Really the static forces on the beam come out equal (tension
and compression). The dynamic forces are the tractor moving force vectors causing the soil to lift up
and roll over.  What I am unable to get clear in my mind are the side forces and how they become
linear with the pulling axis. Maybe the hitch on the tractor counteracts that a bit and the landslide
in the furrow does as well.  A fairly complex equation. I guess the hitch has to try to rotate the
plow a bit to the plowed soil side and the resistance of the rolling soil counter acts that force and
then stays straight.  I've seen a force diagram for tag plows and even three point plows somewhere in
an old JD book I think.   First I have to figure out where to look and maybe I might find 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
charlie hill
Sent: Wednesday, August 20, 2014 4:44 PM
To: Antique tractor email discussion group
Subject: Re: [AT] McCormick plow

I agree Dean.  I can see the point of the person that wrote that.
I have no clue now where I read it.

I'm trying to think back and remember my statics and dynamics course
in college.  There is a way to resolve the forces into one vector but I 
don't remember
how.  Maybe someone else does.

I guess the writer was looking at it from the point of view of the plow.  If 
you were the
plow and lets say that your nose was the plow point and the tongue was bent 
around
and shoved up your rear,  I suspect you'd think you were being pushed. 
grins

Charlie
-----Original Message----- 
From: Dean VP
Sent: Wednesday, August 20, 2014 6:35 PM
To: 'Antique tractor email discussion group'
Subject: Re: [AT] McCormick plow

Charlie,

Never quite thought of it that way before. Intelesting!  However,  I think 
something has to pull the
pushing part though!  :-)  I guess I always think of pushing is when the 
power to push is behind the
load. Another way to look at this is: The majority of the beam is pulling. 
Then as the beam turns down
it starts pushing.

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
charlie hill
Sent: Wednesday, August 20, 2014 12:06 PM
To: Antique tractor email discussion group
Subject: Re: [AT] McCormick plow

wow, that's a rig I've never seen before.  The only tractor
I know that pulls a plow up front is an Allis Chalmers G.
Didn't know anyone else ever did that.   By the way, I read
once that you push a plow instead of pulling it as I've always said.
I guess if you think about it that is correct because the tongue runs
back to the rear of it and pushes it.

Charlie

-----Original Message----- 
From: Ron Cook
Sent: Wednesday, August 20, 2014 10:38 AM
To: Antique tractor email discussion group
Subject: Re: [AT] McCormick plow

Charlie,
     No this one actually pulls from the front axle which I wouldn't
do.  For two reasons.  #1 it looks like a good way to break something
expensive and #2 I don't have that front attachment part anyway.  This
plow is probably from a straight A and I think is an A192 plow.  The
Super A uses the A193 plow that pulls from the drawbar flipped to the
forward position.  Much better idea I think, and I can make that
attachement, or find one and put it on the plow which would be much
easier.  None of it is very tough to manufacture.  Pretty simple and
crude tool.  Must work, though.  It is worn out.

Ron
On 8/20/2014 8:27 AM, charlie hill wrote:
> Ron is that plow a  single point hitch with a notch cut in the front of it
> that slides into the tractor hitch or how does it attach to the A?
> The single point (with the notch in the tongue) didn't come along until
> the mid 50's to early 60's I think.
>
> Charlie
>

_______________________________________________
AT mailing list
http://www.antique-tractor.com/mailman/listinfo/at

_______________________________________________
AT mailing list
http://www.antique-tractor.com/mailman/listinfo/at

_______________________________________________
AT mailing list
http://www.antique-tractor.com/mailman/listinfo/at 

_______________________________________________
AT mailing list
http://www.antique-tractor.com/mailman/listinfo/at




More information about the AT mailing list