[TheForge] Speaking of hammers

[Jerry Frost]

----- Original Message -----
From: <schade@acegroup.cc>
To: <theforge@mailman.qth.net>
Sent: Saturday, April 17, 2004 8:06 AM
Subject: Re: [TheForge] Speaking of hammers


>
> On Apr 16, 2004, at 6:37 PM, Jerry Frost wrote:
>
> > I agree, Mark did the work and deserves to get paid for his plans.
> > Frosty
> > ------------------------
> >
>
> Calling Mark Krauses booklet "plans" is quite a leap. He has drawings
> showing the plumbing of the Nazel system and shows how he adapted the
> Nazel system to a home built hammer. Nothing wrong with that but if
> anyone thinks they are getting a set of "plans" as in measured drawings
> they will be disappointed.
>
> This is not meant to discredit Mark in any way. He is a very clever guy
> and
> was very generous with his time in helping me to understand the
> circuit. If
> you are interested in a self contained hammer this booklet helps to
> visualize
> the Nazel circuit.
>
> It's just not plans.
>
> Bob
>


I've heard this about Mark's booklet and his willingness to help. Still, in
many cases a clear illustration of operating principle is better than a
specific "plan". For me anyway, considering my resources. Much of what I
have to work with is scrounged or improvised, so I end up playing it by ear
a lot.

After past self contained hammer threads where Mark's adaptations were
discussed and a sketch or two posted I did some patent server research. I
frankly find the Nazel valving pretty incomprenensible but I didn't spend a
lot of time trying to decipher it. Even the far simpler Massey valving
scheme had me slapping my head trying to adapt it to a piston or spool
valve, the closest I came was a flat slider. There's also a lot of extra
plumbing to make them work and the less airway volume involved the more
power the ram(s) have available to hit things.

Anyway, I'm not too interested in Mark's adaptation as I can make the Massey
scheme work for $20 with a single1/4 turn ball valve if I decide I don't
want the ram up at idle. I'm pretty sure  I DO want the ram up at idle
though and using the Massey scheme I can modify a plumbing valve by adding a
check valve to it. IF that's all I want it to do.

Where it gets a more complicated is making the valve for the clamp/dead blow
function. For simple cycling and idling a ball valve and check will work
fine but to make it clamp the circuit has to SMOOTHLY transition from
holding the ram up to holding it down.

The Massey drawings are clear about how to do this, the valve is wedge
shaped. At idle the check valve lets air pass to the bottom of the tup
ram(s) and stops it from passing to their top and the ram stays up. Doing
work, the wide part of the valve progressively blocks the bypass airway and
the ram cycles as hard and far as the treadle tells it to. The dead blow is
the same as clamping except for speed, the dead blow slams into the anvil
and just stops.

With a simple change to the linkage, the valve rotates the opposite
direction and the narrow side of the valve is brought into play. Like a
knife blade the narrow side of the valve bisects the bypass airway instead
of blocking it. One side of the "blade" is the UP side of the check valve
and the other is the DOWN side. With a little practice you can bring the ram
down as slowly as you'd like, "hoover" it or put down some serious clamp
pressure.

Okay, a plumbing ball valve is literally a ball with a hole through it so
both sides are wide. While adding a check valve to one would give you a
clamp/dead blow function the wide valve between the up/idle and down/clamp
position would block the bypass airway and the ram would go to full cycle.
This would be . . . BAD. <grin>

One last thing: Single blows are a function of an escapement and fast return
springs on the linkage and isn't part of the valve. Basically you press the
treadle, the valve sends the ram at the anvil and a toggle or other
mechanism interacting with the crank, conecting rod or other reciprocating
part of the compressor disengages the valve from the linkage before a second
blow occurs. When you let the treadle up, the escapement resets.

Frosty
------------------------
If it ain't forged
it ain't real.
Wrought iron is.
The FrostWorks

Meadow Lakes, AK.