[TheForge] Cylinder Size

Tue Jul 15 23:47:00 2003

Hi Chuck;
Somewhere in the this contraption there is a knob or bolt or something that
trips the pilot valve, lets say it is right on top of the hammer head, and
the pilot valve is  1" below  the top of the stroke. so when the hammer
moves down 1" the air reverses and and starts building press. to raise the
hammer, gravity and enertia carry the hammer down to the work after this. If
the pilot valve is 2" inches Below the top of stroke, the hammer must move
down 2" before the air reverses so press is applied to the top of the
cylinder twice as long (ignoring acceloration)and it is twice as long before
press starts building to raise  the hammer so the hammer will hit harder but
slower, by moving the pilot valve further down it would be possible to drive
the hammer clear to the bottom under press in which case it should hit very
hard but would dwell for an instant on the work further down yet and the air
will not reverse and the hammer would clamp the work.
So I figured after opening the throttle valve  wide so the hammer is beating
at max some sort of linkage between  the treadle and the pilot valve would
enable you to vary the position of the valve by depressing the treadle
further. Mind you I've never had anything to do w/ one of these hammers so
this just might not be a good idea.
Randy Mundt
----- Original Message -----
From: "Chuck Robinson" <[email protected]>
To: <[email protected]>
Sent: Tuesday, July 15, 2003 6:51 AM
Subject: Re: [TheForge] Cylinder Size


> Hey Randy,
> I'm pretty familiar with how single and double pilot valves work, but your
> comment "would control where the valve was tripped with the treadle, just
an
> idea for
> more control of the hammer", sound intriguing but leaves me confused as to
> how it would work.
> Sort of like telling me how to remove a car engine: 1. lift hood 2. Remove
> engine.
> Can you elaborate.
> Chuck
>
> ----- Original Message -----
> From: "R.C.Mundt" <[email protected]>
> To: <[email protected]>
> Sent: Monday, July 14, 2003 10:36 PM
> Subject: Re: [TheForge] Cylinder Size
>
>
> > Hi Chuck;
> > If the lower pilot valve( the one that tells the hammer to go up) is
> tripped
> > near the top of the stroke or if you're using a valve setup w/ one pilot
> > valve and spring return, a short burst of air sends the hammer down then
> the
> > bottom side of the cylinder starts filling to raise the hammer, so the
> > hammer beats fast and light.  If the lower pilot valve is triped at the
> > bottom of the stroke air pres. drives the hammer clear to the bottom
then
> > the air reverses and raises the hammer , it beats slow and hard. I
thought
> I
> > would control where the valve was tripped with the treadle, just an idea
> for
> > more control of the hammer.
> > Randy Mundt
> > ----- Original Message -----
> > From: "Chuck Robinson" <[email protected]>
> > To: <[email protected]>
> > Sent: Monday, July 14, 2003 11:05 AM
> > Subject: Re: [TheForge] Cylinder Size
> >
> >
> > > Hey Randy,
> > > I'm confused. Could you elaborate and more clearly state your idea so
I
> > can
> > > understand it?
> > > Chuck
> > > ----- Original Message -----
> > > From: "R.C.Mundt" <[email protected]>
> > > To: <[email protected]>
> > > Sent: Sunday, July 13, 2003 11:24 PM
> > > Subject: Re: [TheForge] Cylinder Size
> > >
> > >
> > > > Just a thought I had if I ever got around to building an air hammer.
I
> > > > thought I would control the position of the lower pilot valve w/ the
> > > > treadle, after the throttle valve was wide open further depressing
the
> > > > treadle would move the pilot valve downward.
> > > > Randy Mundt
> > > > ----- Original Message -----
> > > > From: "Chuck Robinson" <[email protected]>
> > > > To: <[email protected]>
> > > > Sent: Sunday, July 13, 2003 4:20 PM
> > > > Subject: Re: [TheForge] Cylinder Size
> > > >
> > > >
> > > > > Hey Shannell,
> > > > > I'm slowly building a 200 lb air hammer.
> > > > > I don't like the cantilevered hammer slide on the kinyon hammer,
so
> I
> > > > > designed the head to reciprocate inside a vertical square tube
> shell.
> > > The
> > > > > rectangular head has 2 guide grooves milled on opposite sides and
> they
> > > > slide
> > > > > on adjustable steel rails attached to the corresponding inner
faces
> of
> > > the
> > > > > tube. The top adjusting bolts of the guide rails will have a small
> > hole
> > > > > drilled thru the long axis of the bolt to provide lubrication to
the
> > > > sliding
> > > > > surfaces of the hammer head. Since there is no side loading on the
> > head
> > > > wear
> > > > > will be minimal.
> > > > > The only problem I fore see with this design, is where to mount
the
> > > > > adjustable bottom pilot valve, hence the desirability of using a
> > > pneumatic
> > > > > stroke completion sensor.
> > > > > ----- Original Message -----
> > > > > From: "Shannell Sugrue" <[email protected]>
> > > > > To: <[email protected]>
> > > > > Sent: Saturday, July 12, 2003 9:13 AM
> > > > > Subject: Re: [TheForge] Cylinder Size
> > > > >
> > > > >
> > > > > > I use the dual pilot setup and its great, hits hard, fast and is
> > > easily
> > > > > > adjustable on the fly. I think any type of "stroke completion
> > sensor"
> > > > > might
> > > > > > be overkill, I often slide my roller valves when working or when
> > > putting
> > > > a
> > > > > > piece under the hammer.
> > > > > >
> > > > > > ----- Original Message -----
> > > > > > From: "Chuck Robinson" <[email protected]>
> > > > > > To: <[email protected]>
> > > > > > Sent: 12 July, 2003 9:13 AM
> > > > > > Subject: Re: [TheForge] Cylinder Size
> > > > > >
> > > > > >
> > > > > > > One of the problems I've noticed is the relatively soft hit if
> the
> > > > > Kinyon
> > > > > > > style hammers.
> > > > > > >  I suspect the automatic reversing switch in the single pilot
> > > control
> > > > is
> > > > > > > valve is the culprit, since the piston switches direction
before
> > the
> > > > > > hammer
> > > > > > > hits the billet. This also reduces dwell time of the hammer on
> the
> > > > > billet.
> > > > > > > A double pilot control valve will eliminate this problem but
the
> > > > bottom
> > > > > > > pilot valve must be adjusted for the billet thickness.
> > > > > > > Is there any brave soul out there who has played around with
> > stroke
> > > > > > > completion sensors to maximize hammer dwell time and
> automatically
> > > > > adjust
> > > > > > > for stock thickness?
> > > > > > > Chuck
> > > > > > > ----- Original Message -----
> > > > > > > From: <[email protected]>
> > > > > > > To: <[email protected]>
> > > > > > > Sent: Friday, July 11, 2003 2:13 PM
> > > > > > > Subject: Re: [TheForge] Cylinder Size
> > > > > > >
> > > > > > >
> > > > > > > > If you go with a larger bore on the cylinder you would need
to
> > > also
> > > > > have
> > > > > > > the ports on the cylinder and and the valve be as large as
> > > > possible.The
> > > > > > > trick is the amount of air flow you can get through the system
> as
> > > fast
> > > > > as
> > > > > > > you can get.You can have a large bore cylinder with big ports
> but
> > if
> > > > the
> > > > > > > valve ports are small and have a low cv rating then it will
not
> > > cycle
> > > > > that
> > > > > > > fast.I have a 2" bore cylinder on my 25lbr with 3/8" ports on
> both
> > > the
> > > > > > > valve(which also has a high cv rate)and cylinder.it will do
240
> > > beats
> > > > > > > /minute before that I had the same style valve with 1/4" ports
> and
> > a
> > > > > lower
> > > > > > > cv and could only get 180 beats/minute
> > > > > > > >
> > > > > > > > --
> > > > > > > > Bob
> > > > > > > > HotAnvil Forge
> > > > > > > > http://members.tripod.com/hotanvil_forge
> > > > > > > >
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