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Why hydraulics?


#1

I’ve been looking to get a press for punching parts and pressing
some pendants. I’m wondering why everyone is using hydraulic presses
now. Looking at the presses available and costs I’m inclined towards
a screw press. I understand these were widely used in the industry
some years ago, now all I see are hydraulics. Can anyone fill me in
on why the change?

Ben Brauchler


#2

Hi Ben,

Couple of reasons why the hydraulics won out for small studio work.

(A) at least in the states, screw (fly) presses are hard to find
outside the north-east corridor. (Much easier in the UK, I’m given
to understand.) (B) screw presses are heavy and a pain in the tail to
move. Equivalent tonnage hydraulic presses are about 1/5th the
weight.

(Trust me on this, I used to own a giant fly press. It broke the
driveway when I brought it home.) (PS. > I wish to publicly …) ©
manual hydraulics don’t hit with the same effective force, but they
do have the major advantage that if you get a finger caught
somewhere, it’s very easy to STOP PUMPING. A screw press would
just smash your finger.

(D) once you get into more advanced things like deep draw kits,
punches and bending/breaking dies, you can do those with your hands
in the press (see point C) so that you can guide/examine the work as
it happens, where you simply couldn’t do that with a faster acting
press. (E) thanks to the efforts of Lee Marshall and Phil Porier of
Bonny Doon Presses, there’s a wide range of easily available tooling
for the hydraulics, so that you don’t have to spend half your time
machining up the tools to make the work before you even get started.
(disclosure: I work with Lee, and Phil’s a friend, so I’m hardly
impartial.)

Screw presses do have the advantage that they dump a lot of energy
into the work piece in a very short time, which lets them move it
much further, much faster than the slow ‘squeeeeeeeeze’ of a
hydraulic can, but for most people, with most work, that advantage
doesn’t make it worth the effort to scrounge one up, or tool it up
once they’ve found it. (I sold mine, and I do have the gear to tool
it up, if that tells you anything.) (If you want to see pictures of
the biggest screw press I’ve ever seen, and the fun and joy I had
dragging its frozen carcass out of a half demolished warehouse in
Detroit, the whole sordid saga is laid out here:
http://www.ganoksin.com/gnkurl/ep81i6

Hope that was of some use.

Regards,
Brian


#3

Mr. Braughler,

You are correct - you could effectively use a screw type or
mechanical press and have it work very well. The explanation of why
hydraulics rather thanmechanics follows:

In the United States, hydraulics in general began replacing many
mechanicalsystems shortly after the Morrill Act of 1876. Presses are
just one of many areas where hydraulics dominated the field. In
general industry, hydraulics tend to be a better choice over other
means of producing force and motionwhen the task at hand requires 40
or more horsepower. Most of the basic specifics for choosing
hydraulics instead of mechanics are :

1 - Size and Force - Hydraulics produce the highest power / force to
size /weight ratio;

2 - Speed - Hydraulic presses over approximately 40 horsepower are
capable of many more cost efficient speed variations than most
mechanical presses;

3 - Flexibility - Hydraulic units can be installed in a variety of
locations that would be a significant challenge for mechanics;

4 - When higher horsepower is required, hydraulics can be
incorporated withmuch more cost efficient and sophisticated control
systems than the mechanical equivalent;

This info doesn’t even begin to scratch a good explanation’s basics,
however, if you would like additional explanation, please feel free
to e-mail me on or off line.

Best Regards,
Bob A. DeMarcki


#4

Speaking for my own jewelry uses, I can tell you I use my Bonny Doon
because of the power it has and the wonderful array of specialized
tooling available. I have a screw press that came with the old RT
blanking system (which I never mastered). And yes, a screw press can
do certain tasks like a hydraulic press. cutting shapes with
blanking dies, forming with silhouette dies and embossing. But I
love the other accessories that BD offers for more specific tasks
that a screw press can’t perform, especially all the bracelet
options. My first press was a manual then I upgraded to an electric.
Now I only need the strength of my index finger to get to maximum
pressure when needed. Love it!


#5

Gee. why not continue to drag a sled rather than a wagon with
wheels? Sorry, I couldn’t resist.

The advantages of using hydraulics is the exquisite precise pressure
control available with hydraulics. To achieve that same level of
control with a sledge hammer method is much more difficult, and can
take years of experience to develop.

Using a screw press for stamping out parts is a time honored method
of making parts, and can be quite effective if you get a large one.
I have a fly press in the shop, and we use it daily for stamping the
patent on the knew concepts saws. The lead filled brass
covered balls are 4" in diameter, and swing in a 26" diameter
circle. The total weight is about 400 pounds and is bolted to a
significant bench that doesn’t move when the press is used.

Think carefully about all of the ancillary needs of the system that
you choose. It is not a slam dunk easy peasy decision. Subsequent
moving issues need to be thought about before you pull the trigger.

Lee (the saw guy)


#6

Hi Brian,

Interesting to read your experience with the screw press, and sorry
that you and it were not to have a happy relationship.

Im of the opposite view and have embraced these presses and all the
other machines available to simplify and speed up the making process
of my products.

So to all you other metal workers, if you come across machines like
this, consider them carefully. Tools and machines open the door to
new products that a bench jeweller cannot make economically.

It has of course to start in your head.

What do you want to do with your life?

You need ideas to turn into products, somewhere to make them with
the tools to do so and finally a market for them that reflects what
you make.

For example, take a simple thing like a button. you can spend all
day making one by repousse on your pitch block, or you have a die
made in tool steel, along with a punch and die for the blanking of
the disk.

Then with a press like you Brian had, stamp out at least one a
minuite, or say 100 an hour. Theres just no comparison. your press
costs and die costs will be repaid within a few months.

Furthermore your hydraulic press, despite the same tonnage, will not
match that production rate. Time is of the essence in this trade;.

We all have fixed costs whatever we make, so anything that reduces
our variable costs is just more profit, or more dollars per hour for
our time. Makes sense really.

So what else do people wear? in addition to rings, bracelets,
necklaces? well, there are cuff links, buttons, buckles and tie
pins.

I like making buckles. Its as follows.

The buckle is in 2 parts. the back, which is standard for this
shape. The front. that is also a standard shape. a 3in by 2 in oval.

Both are blanked out on a 10 ton power press, dont saw them by
hand!! However this front is of a no of different designs. For
example one series is the “great age of steam” comprising 5 designs.
The one best known is Stevenson’s rocket.

This is made with a tool steel die and can be minted in brass,
copper or s/silver. then these 2 parts are rivetted together, leather
of the right weight and quality is affixed and off it goes to a happy
customer.

To mint to coin proof quality needs 100 tons. you would need
something bigger than the current hydraulic presses offered to the
bench jeweller to make these.

Ted.


#7

Hello Brian,

Your story was simply amazing! You are such a gifted storyteller! I
thoroughly enjoyed reading and “experiencing” it!

Best Regards,
Julie