Gents,

After recently completing a week long course on Damascus at the ABS
school (Taught by MS Steve Dunn, incidentally) I am considering the
procurement of a forging press. However, I am a complete novice when
it comes to hydraulics, which limits my ability to make any sort of
decision.

At the ABS school, there is a press made by Uncle Al of Riverside
Machine (http://www.riversidemachine.net/item16342.ctlg). The two
features that seemed important were 1) it would accept interchangeable
dies and 2) the foot pedal would lower the press at a constant speed,
it would hold at a certain level, or if you took your foot off it
would raise up.

I was with MS Chris Marks (http://www.marksforge.com/) when he used
this press to create a demo billet of damascus and remember him saying
it wasn't strong enough. I believe his press was closer to 50 tons.

Anyway, this brings me to my question. Does anyone have any
experience with or opinions on the Harbor Freight 50 Ton press found
he
http://www.harborfreight.com/cpi/cta...emnumber=46768

My thoughts, questions and observations:
- What powers this press? Can you just hook up a compressor? I have
a 5hp / 60 gal / 13.3 cfm @90 psi unit. Would that work?
- How would one convert the unit to be foot pedal operated?
- It looks like one would have to raise the bottom table up quite
high to use this press on a billet of steel that was only 2-4" tall.
- The manual says that you basically use the air supply to lower the
ram to the material and then pump it by hand. Can't you just keep
using the air pressure to ram into the material? Or does it lack
sufficient force in that manner?
- It looks like it would be difficult to fit dies onto this unit.

I'm only aware of two commercially available presses. Uncle Al's, and
the one from Carolina Knives.
(http://www.carolinaknives.com/press/press.html) If anyone knows of
others I would appreciate a reference.

Finally, would I be able to build my own press using the $70 HF 20 ton
bottle jack discussed in the other recent thread? I am a good welder
and a reasonable metal worker and handy sort of guy in general. I
just don't know anything about hydraulics...

Thanks in advance,

John P.

John, I'm a blacksmith and I have a powered, hydraulic forging press
that I've used to make Damascus with. I haven't seen Steve Dunn demo,
don't know his techniques, but I don't think you're going at this in a
way that will work.

In my experience, the main issue in forging or forge welding with a
press is being able to drive the press tooling into the work faster than
the work cools. About the worst case is welding a Damascus billet--big
flat dies that soak up the heat rapidly. If your pieces are clean and
lightly fluxed, just squishing them a little bit (maybe 1/8" over a 2"
billet) should make a good weld. This doesn't take a lot of pressure; I
haven't measured it when welding (paying attention to the weld, not the
press), but I bet my 30 ton press wasn't even up to 15 tons. I think
that for both general purpose forging and for making Damascus, a 20 ton
press will do the job. More tons are always better , but I've never
had much need to go over 30. For typical size work, if your press is
actually pushing with 20-30 tons, it tells me that the work is getting
too cool to forge nicely.

So why won't the HF press do the job?--speed of travel during forging.
It does have a means to move the press tooling up and down rapidly when
under no load (via air). The problem is that air can't give you a lot of
pressure in the dies. The manual on your press says air at 100 psi; my
press is at an internal pressure of about 2000psi when the dies are at
30 tons pressure. Quite a difference. How the HF press works is you use
air to move the dies into contact with the work, then switch to the hand
pump, like with most shop hydraulic presses. This is *very* slow, way
too slow for forging.

Here's an example. My press has a hydraulic cylinder with a 6" diameter
piston. The area of the piston times the pump pressure gives you the
amount of tonnage the cylinder will put on the dies. In this case, a 6"
diameter piston has 28 square inches of area. Multiply this by 2000psi
and you get 56,000 pounds pressure, 28 tons (I guess my press is
'almost' 30 tons). The issue is how fast you can move at this pressure.
My press moves 1/4" per second at 30 (alright, 28) tons pressure. This
takes a pump driven by a 3HP motor, not something you can contemplate
doing with a hand pump. Maybe you could motorize the pump, but it isn't
designed to work at this kind of speed and I'd expect it would fall
apart quickly.

This also means that modifying a 20 ton shop press (hand pump) won't get
you where you want to go. You could imagine adding a motorized pump to
such a press, but the cylinder has no provision for the high pressure
plumbing. You could replace cyinder and pump, but you might as well
build the whole thing at that point.

Being a welder, I recommend you build a press. There are some really
excellent plans available by Jim Batson. You can get these plans from
Norm Larson ). Norm has most every blacksmithing
book available for sale, and he's a great guy. I'm sure you could also
get the plans from Jim, but I don't have contact info for him. Jim not
only gives you detailed press plans, he also gives you a good
understanding of how hydraulics work and how to estimate mechanical
stresses in your press (if you want to use different material sizes, or
change the press tonnage). I think Jim has two booklets out now, one on
an open sided press (C style) and another on H style presses. He also
discusses converting a motorized log splitter into a forging press.

Rather than using a combination of air and hydraulic, Jim's design uses
a log splitter pump to achieve fast motion when not loaded. Log splitter
pumps will pump at a high volume rate as long as the pressure is low,
switching over to a lower volume rate at high pressures. This keeps your
motor HP down. My press has a pump that runs the 6" cylinder at 1" per
second up to around 600 psi, above that, the dies slow to 1/4" per second.

Some specific comments:
1. Don't bend over with your eyes right next to a billet being welded in
the press. 1800 degree F flux can unexpectedly squirt out from between
the layers. You don't want your face anywhere near this, even with
safety glasses.
2. I find 1" per second travel (unloaded) plenty fast. I do a lot of
different kind of work on my press. I originally set it up for 2" per
second. This is *way* too exciting if you're doing any bending, almost
out of control.
3. The log splitter pumps claim that they work up to 3600 rpm. This was
how mine was originally set up to get 2" per second. The pump just
screams at this speed; not only don't you need 2" per second, but I
don't see how a pump making that much noise can possibly last long. I
now run mine at 1750 rpm, much quieter.

Here's a picture of mine:
http://www.metalworking.com/DropBox/...iles/Press.jpg
http://www.metalworking.com/DropBox/...iles/Press.txt
It probably cost me about $700, given some careful scrounging. Note that
the email address in the text is no longer valid.

Steve


John P. wrote:

Gents,

After recently completing a week long course on Damascus at the ABS
school (Taught by MS Steve Dunn, incidentally) I am considering the
procurement of a forging press. However, I am a complete novice when
it comes to hydraulics, which limits my ability to make any sort of
decision.

At the ABS school, there is a press made by Uncle Al of Riverside
Machine (http://www.riversidemachine.net/item16342.ctlg). The two
features that seemed important were 1) it would accept interchangeable
dies and 2) the foot pedal would lower the press at a constant speed,
it would hold at a certain level, or if you took your foot off it
would raise up.

I was with MS Chris Marks (http://www.marksforge.com/) when he used
this press to create a demo billet of damascus and remember him saying
it wasn't strong enough. I believe his press was closer to 50 tons.

Anyway, this brings me to my question. Does anyone have any
experience with or opinions on the Harbor Freight 50 Ton press found
he
http://www.harborfreight.com/cpi/cta...emnumber=46768

My thoughts, questions and observations:
- What powers this press? Can you just hook up a compressor? I have
a 5hp / 60 gal / 13.3 cfm @90 psi unit. Would that work?
- How would one convert the unit to be foot pedal operated?
- It looks like one would have to raise the bottom table up quite
high to use this press on a billet of steel that was only 2-4" tall.
- The manual says that you basically use the air supply to lower the
ram to the material and then pump it by hand. Can't you just keep
using the air pressure to ram into the material? Or does it lack
sufficient force in that manner?
- It looks like it would be difficult to fit dies onto this unit.

I'm only aware of two commercially available presses. Uncle Al's, and
the one from Carolina Knives.
(http://www.carolinaknives.com/press/press.html) If anyone knows of
others I would appreciate a reference.

Finally, would I be able to build my own press using the $70 HF 20 ton
bottle jack discussed in the other recent thread? I am a good welder
and a reasonable metal worker and handy sort of guy in general. I
just don't know anything about hydraulics...

Thanks in advance,

John P.

First of all Steve, thanks very much for the thorough response. It is
much appreciated.

On Sat, 31 Dec 2005 09:53:46 -0500, Steve Smith
wrote:

snip

So why won't the HF press do the job?--speed of travel during forging.

I totally agree with your comments regarding the speed and heat of the
welding process, and you confirmed for me that the air simply lacks
the power once the die comes in contact with the work material.

snip

This also means that modifying a 20 ton shop press (hand pump) won't get
you where you want to go.

Interestingly, on another thread Pete Stanaitis briefly describes how
he is employing one of those hand pumps to make Damascus. I'm waiting
on his response to learn more about how he's doing this. But I take
your point that if the jack isn't designed for this it could fail
rather quickly.

snip

Being a welder, I recommend you build a press. There are some really
excellent plans available by Jim Batson.

Yes, Don Fogg talks about that a lot on his site, but I'm just scared
of starting a project I can't complete. I really know absolutely zero
about hydraulics. Still, everyone says that Dr. Jim's book does a
good job of teaching. I guess I need to get a copy and see what I can
learn.

Thanks again,

John P.

Steve Smith wrote:


snipped


So why won't the HF press do the job?--speed of travel during forging.
It does have a means to move the press tooling up and down rapidly when
under no load (via air). The problem is that air can't give you a lot of
pressure in the dies. The manual on your press says air at 100 psi; my
press is at an internal pressure of about 2000psi when the dies are at
30 tons pressure. Quite a difference. How the HF press works is you use
air to move the dies into contact with the work, then switch to the hand
pump, like with most shop hydraulic presses. This is *very* slow, way
too slow for forging.

I agree that the press speed is probably way too slow for the work in
question, but I think you misunderstand how the air/hydraulic presses
work. The 100 psi air does not directly act on the press piston, it
operates a reciprocating air motor that operates a small pump cylinder
for the oil, same as the manual pump cylinder works. Given proper air
line pressure, the air operated pump will build pressure up to the
hydraulic relief valve setting just as the manual pump will.


Here's an example. My press has a hydraulic cylinder with a 6" diameter
piston. The area of the piston times the pump pressure gives you the
amount of tonnage the cylinder will put on the dies. In this case, a 6"
diameter piston has 28 square inches of area. Multiply this by 2000psi
and you get 56,000 pounds pressure, 28 tons (I guess my press is
'almost' 30 tons). The issue is how fast you can move at this pressure.
My press moves 1/4" per second at 30 (alright, 28) tons pressure. This
takes a pump driven by a 3HP motor, not something you can contemplate
doing with a hand pump. Maybe you could motorize the pump, but it isn't
designed to work at this kind of speed and I'd expect it would fall
apart quickly.

You have a direct acting powered hydraulic press, more or less the same
as a log splitter, this is quite different from the basic hydraulic jack
powered H press.


This also means that modifying a 20 ton shop press (hand pump) won't get
you where you want to go. You could imagine adding a motorized pump to
such a press, but the cylinder has no provision for the high pressure
plumbing. You could replace cyinder and pump, but you might as well
build the whole thing at that point.

I disagree, the commercially available 20T H presses are quite
inexpensive and will save a lot of time and effort tracking down the
steel, welding and trying to keep things square. My recommendation would
be to use a commercial 20T press frame as a starting point. The 20T jack
can readily be used separately as a normal jack.

You should be able to find a suitable hydraulic cylinder, valves and
pump unit from a place like http://www.surpluscenter.com and have a fast
powered unit operating in short order.

more snipped

Pete C.

Hello, Steve.
I am not a knife maker, but I have used the HF 20 air over hydraullic
jack in a 20 ton press to weld damascus billets. I don't understand
why you say to use the hand pump. I never do. The air pressure does
the same thing that the hand pump does and to the same degree, as far as
I can tell. We use two of these presses on a pretty regular basis, one
for general work (and the occasional billet); the other for pressing
bearings where we approach the 20 ton limit often.
I agree that you don't need a lot of tonnage to weld. A friend of
mine, Mike Blue, from Cannon Falls MN got me started with this HF
air/hydraulic press idea when he said that he turns his 50 ton press
down to about 12 ton for welding damascus billets.
As far as speed goes: certainly, if I had the money and the time,
I'd go with a "regular", noisy 50 ton all hydraulic press. The ones I
have seen, particularly those with the 2 speed pump, move a lot faster,
and as you said, speed is important.
My press is set up with two foot valves. One for down (the stock air
cylinder) and one for up (a 1 inch cylinder I added to the release
valve). I move down to the point where I am close to the thicknes of
the billet before I take it out of the fire. Then press, release a
little, press a little, etc. With the two valves, the ram only goes up
as far as I tell it to, not a full or large retraction. I get about 4
"squeezes" per heat.

I just put a few pix up on my website. www.spaco.org/Press.htm

Not trying to be argumentative, just reporting,
Pete Stanaitis
----------------------------------

Steve Smith wrote:

John, I'm a blacksmith and I have a powered, hydraulic forging press
that I've used to make Damascus with. I haven't seen Steve Dunn demo,
don't know his techniques, but I don't think you're going at this in a
way that will work.

In my experience, the main issue in forging or forge welding with a
press is being able to drive the press tooling into the work faster than
the work cools. About the worst case is welding a Damascus billet--big
flat dies that soak up the heat rapidly. If your pieces are clean and
lightly fluxed, just squishing them a little bit (maybe 1/8" over a 2"
billet) should make a good weld. This doesn't take a lot of pressure; I
haven't measured it when welding (paying attention to the weld, not the
press), but I bet my 30 ton press wasn't even up to 15 tons. I think
that for both general purpose forging and for making Damascus, a 20 ton
press will do the job. More tons are always better , but I've never
had much need to go over 30. For typical size work, if your press is
actually pushing with 20-30 tons, it tells me that the work is getting
too cool to forge nicely.

So why won't the HF press do the job?--speed of travel during forging.
It does have a means to move the press tooling up and down rapidly when
under no load (via air). The problem is that air can't give you a lot of
pressure in the dies. The manual on your press says air at 100 psi; my
press is at an internal pressure of about 2000psi when the dies are at
30 tons pressure. Quite a difference. How the HF press works is you use
air to move the dies into contact with the work, then switch to the hand
pump, like with most shop hydraulic presses. This is *very* slow, way
too slow for forging.
Here's an example. My press has a hydraulic cylinder with a 6" diameter
piston. The area of the piston times the pump pressure gives you the
amount of tonnage the cylinder will put on the dies. In this case, a 6"
diameter piston has 28 square inches of area. Multiply this by 2000psi
and you get 56,000 pounds pressure, 28 tons (I guess my press is
'almost' 30 tons). The issue is how fast you can move at this pressure.
My press moves 1/4" per second at 30 (alright, 28) tons pressure. This
takes a pump driven by a 3HP motor, not something you can contemplate
doing with a hand pump. Maybe you could motorize the pump, but it isn't
designed to work at this kind of speed and I'd expect it would fall
apart quickly.

This also means that modifying a 20 ton shop press (hand pump) won't get
you where you want to go. You could imagine adding a motorized pump to
such a press, but the cylinder has no provision for the high pressure
plumbing. You could replace cyinder and pump, but you might as well
build the whole thing at that point.

Being a welder, I recommend you build a press. There are some really
excellent plans available by Jim Batson. You can get these plans from
Norm Larson ). Norm has most every blacksmithing
book available for sale, and he's a great guy. I'm sure you could also
get the plans from Jim, but I don't have contact info for him. Jim not
only gives you detailed press plans, he also gives you a good
understanding of how hydraulics work and how to estimate mechanical
stresses in your press (if you want to use different material sizes, or
change the press tonnage). I think Jim has two booklets out now, one on
an open sided press (C style) and another on H style presses. He also
discusses converting a motorized log splitter into a forging press.

Rather than using a combination of air and hydraulic, Jim's design uses
a log splitter pump to achieve fast motion when not loaded. Log splitter
pumps will pump at a high volume rate as long as the pressure is low,
switching over to a lower volume rate at high pressures. This keeps your
motor HP down. My press has a pump that runs the 6" cylinder at 1" per
second up to around 600 psi, above that, the dies slow to 1/4" per second.

Some specific comments:
1. Don't bend over with your eyes right next to a billet being welded in
the press. 1800 degree F flux can unexpectedly squirt out from between
the layers. You don't want your face anywhere near this, even with
safety glasses.
2. I find 1" per second travel (unloaded) plenty fast. I do a lot of
different kind of work on my press. I originally set it up for 2" per
second. This is *way* too exciting if you're doing any bending, almost
out of control.
3. The log splitter pumps claim that they work up to 3600 rpm. This was
how mine was originally set up to get 2" per second. The pump just
screams at this speed; not only don't you need 2" per second, but I
don't see how a pump making that much noise can possibly last long. I
now run mine at 1750 rpm, much quieter.

Here's a picture of mine:
http://www.metalworking.com/DropBox/...iles/Press.jpg
http://www.metalworking.com/DropBox/...iles/Press.txt
It probably cost me about $700, given some careful scrounging. Note that
the email address in the text is no longer valid.

Steve


John P. wrote:

Gents,

After recently completing a week long course on Damascus at the ABS
school (Taught by MS Steve Dunn, incidentally) I am considering the
procurement of a forging press. However, I am a complete novice when
it comes to hydraulics, which limits my ability to make any sort of
decision.

At the ABS school, there is a press made by Uncle Al of Riverside
Machine (http://www.riversidemachine.net/item16342.ctlg). The two
features that seemed important were 1) it would accept interchangeable
dies and 2) the foot pedal would lower the press at a constant speed,
it would hold at a certain level, or if you took your foot off it
would raise up.

I was with MS Chris Marks (http://www.marksforge.com/) when he used
this press to create a demo billet of damascus and remember him saying
it wasn't strong enough. I believe his press was closer to 50 tons.

Anyway, this brings me to my question. Does anyone have any
experience with or opinions on the Harbor Freight 50 Ton press found
he
http://www.harborfreight.com/cpi/cta...emnumber=46768

My thoughts, questions and observations:
- What powers this press? Can you just hook up a compressor? I have
a 5hp / 60 gal / 13.3 cfm @90 psi unit. Would that work?
- How would one convert the unit to be foot pedal operated?
- It looks like one would have to raise the bottom table up quite
high to use this press on a billet of steel that was only 2-4" tall.
- The manual says that you basically use the air supply to lower the
ram to the material and then pump it by hand. Can't you just keep
using the air pressure to ram into the material? Or does it lack
sufficient force in that manner?
- It looks like it would be difficult to fit dies onto this unit.

I'm only aware of two commercially available presses. Uncle Al's, and
the one from Carolina Knives.
(http://www.carolinaknives.com/press/press.html) If anyone knows of
others I would appreciate a reference.

Finally, would I be able to build my own press using the $70 HF 20 ton
bottle jack discussed in the other recent thread? I am a good welder
and a reasonable metal worker and handy sort of guy in general. I
just don't know anything about hydraulics...

Thanks in advance,

John P.

Nice shop, Pete, and nicely arranged. Bill.

Pete C. wrote:

Steve Smith wrote:



snipped



So why won't the HF press do the job?--speed of travel during forging.
It does have a means to move the press tooling up and down rapidly when
under no load (via air). The problem is that air can't give you a lot of
pressure in the dies. The manual on your press says air at 100 psi; my
press is at an internal pressure of about 2000psi when the dies are at
30 tons pressure. Quite a difference. How the HF press works is you use
air to move the dies into contact with the work, then switch to the hand
pump, like with most shop hydraulic presses. This is *very* slow, way
too slow for forging.



I agree that the press speed is probably way too slow for the work in
question, but I think you misunderstand how the air/hydraulic presses
work. The 100 psi air does not directly act on the press piston, it
operates a reciprocating air motor that operates a small pump cylinder
for the oil, same as the manual pump cylinder works. Given proper air
line pressure, the air operated pump will build pressure up to the
hydraulic relief valve setting just as the manual pump will.



OK, I don't have a clue (except the one you just gave me) about
air/hydraulic. I didn't actually see anything like that in the manual
(which recommended switching to the hand pump), but it was a quick skim.
This does still leave the question of if the press moves fast enough;
the instruction manual is (typically) pretty thin on info like that.
I'll change my comment to "I don't know".

This also means that modifying a 20 ton shop press (hand pump) won't get
you where you want to go. You could imagine adding a motorized pump to
such a press, but the cylinder has no provision for the high pressure
plumbing. You could replace cyinder and pump, but you might as well
build the whole thing at that point.



I disagree, the commercially available 20T H presses are quite
inexpensive and will save a lot of time and effort tracking down the
steel, welding and trying to keep things square. My recommendation would
be to use a commercial 20T press frame as a starting point. The 20T jack
can readily be used separately as a normal jack.

You should be able to find a suitable hydraulic cylinder, valves and
pump unit from a place like http://www.surpluscenter.com and have a fast
powered unit operating in short order.

more snipped

Pete C.


I should have added that if you live in a rural area, see if you can
find a tractor junkyard (or just a well stocked junkyard). I bought
several cylinders off of the one I used to live near.

Steve

As I commented to the other Pete, I don't know a thing about
air/hydraulic. How come the instructions recommend squeezing the air
valve and pumping the handle at the same time? Hopefully you don't have
to rub your tummy too.

Noisy? Sounds like my press...

So the air/hydraulic uses air to turn a hydraulic pump?

Steve

spaco wrote:

Hello, Steve.
I am not a knife maker, but I have used the HF 20 air over
hydraullic jack in a 20 ton press to weld damascus billets. I don't
understand why you say to use the hand pump. I never do. The air
pressure does the same thing that the hand pump does and to the same
degree, as far as I can tell. We use two of these presses on a pretty
regular basis, one for general work (and the occasional billet); the
other for pressing bearings where we approach the 20 ton limit often.
I agree that you don't need a lot of tonnage to weld. A friend of
mine, Mike Blue, from Cannon Falls MN got me started with this HF
air/hydraulic press idea when he said that he turns his 50 ton press
down to about 12 ton for welding damascus billets.
As far as speed goes: certainly, if I had the money and the time,
I'd go with a "regular", noisy 50 ton all hydraulic press. The ones I
have seen, particularly those with the 2 speed pump, move a lot
faster, and as you said, speed is important.
My press is set up with two foot valves. One for down (the stock air
cylinder) and one for up (a 1 inch cylinder I added to the release
valve). I move down to the point where I am close to the thicknes of
the billet before I take it out of the fire. Then press, release a
little, press a little, etc. With the two valves, the ram only goes
up as far as I tell it to, not a full or large retraction. I get
about 4 "squeezes" per heat.

I just put a few pix up on my website. www.spaco.org/Press.htm

Not trying to be argumentative, just reporting,
Pete Stanaitis
----------------------------------

Steve Smith wrote:

John, I'm a blacksmith and I have a powered, hydraulic forging press
that I've used to make Damascus with. I haven't seen Steve Dunn demo,
don't know his techniques, but I don't think you're going at this in
a way that will work.

In my experience, the main issue in forging or forge welding with a
press is being able to drive the press tooling into the work faster
than the work cools. About the worst case is welding a Damascus
billet--big flat dies that soak up the heat rapidly. If your pieces
are clean and lightly fluxed, just squishing them a little bit (maybe
1/8" over a 2" billet) should make a good weld. This doesn't take a
lot of pressure; I haven't measured it when welding (paying attention
to the weld, not the press), but I bet my 30 ton press wasn't even up
to 15 tons. I think that for both general purpose forging and for
making Damascus, a 20 ton press will do the job. More tons are
always better , but I've never had much need to go over 30. For
typical size work, if your press is actually pushing with 20-30 tons,
it tells me that the work is getting too cool to forge nicely.

So why won't the HF press do the job?--speed of travel during
forging. It does have a means to move the press tooling up and down
rapidly when under no load (via air). The problem is that air can't
give you a lot of pressure in the dies. The manual on your press says
air at 100 psi; my press is at an internal pressure of about 2000psi
when the dies are at 30 tons pressure. Quite a difference. How the
HF press works is you use air to move the dies into contact with the
work, then switch to the hand pump, like with most shop hydraulic
presses. This is *very* slow, way too slow for forging.
Here's an example. My press has a hydraulic cylinder with a 6"
diameter piston. The area of the piston times the pump pressure gives
you the amount of tonnage the cylinder will put on the dies. In this
case, a 6" diameter piston has 28 square inches of area. Multiply
this by 2000psi and you get 56,000 pounds pressure, 28 tons (I guess
my press is 'almost' 30 tons). The issue is how fast you can move at
this pressure. My press moves 1/4" per second at 30 (alright, 28)
tons pressure. This takes a pump driven by a 3HP motor, not something
you can contemplate doing with a hand pump. Maybe you could motorize
the pump, but it isn't designed to work at this kind of speed and I'd
expect it would fall apart quickly.

This also means that modifying a 20 ton shop press (hand pump) won't
get you where you want to go. You could imagine adding a motorized
pump to such a press, but the cylinder has no provision for the high
pressure plumbing. You could replace cyinder and pump, but you might
as well build the whole thing at that point.

Being a welder, I recommend you build a press. There are some really
excellent plans available by Jim Batson. You can get these plans from
Norm Larson ). Norm has most every blacksmithing
book available for sale, and he's a great guy. I'm sure you could
also get the plans from Jim, but I don't have contact info for him.
Jim not only gives you detailed press plans, he also gives you a good
understanding of how hydraulics work and how to estimate mechanical
stresses in your press (if you want to use different material sizes,
or change the press tonnage). I think Jim has two booklets out now,
one on an open sided press (C style) and another on H style presses.
He also discusses converting a motorized log splitter into a forging
press.

Rather than using a combination of air and hydraulic, Jim's design
uses a log splitter pump to achieve fast motion when not loaded. Log
splitter pumps will pump at a high volume rate as long as the
pressure is low, switching over to a lower volume rate at high
pressures. This keeps your motor HP down. My press has a pump that
runs the 6" cylinder at 1" per second up to around 600 psi, above
that, the dies slow to 1/4" per second.

Some specific comments:
1. Don't bend over with your eyes right next to a billet being welded
in the press. 1800 degree F flux can unexpectedly squirt out from
between the layers. You don't want your face anywhere near this, even
with safety glasses.
2. I find 1" per second travel (unloaded) plenty fast. I do a lot of
different kind of work on my press. I originally set it up for 2" per
second. This is *way* too exciting if you're doing any bending,
almost out of control.
3. The log splitter pumps claim that they work up to 3600 rpm. This
was how mine was originally set up to get 2" per second. The pump
just screams at this speed; not only don't you need 2" per second,
but I don't see how a pump making that much noise can possibly last
long. I now run mine at 1750 rpm, much quieter.

Here's a picture of mine:
http://www.metalworking.com/DropBox/...iles/Press.jpg
http://www.metalworking.com/DropBox/...iles/Press.txt
It probably cost me about $700, given some careful scrounging. Note
that the email address in the text is no longer valid.

Steve


John P. wrote:

Gents,

After recently completing a week long course on Damascus at the ABS
school (Taught by MS Steve Dunn, incidentally) I am considering the
procurement of a forging press. However, I am a complete novice when
it comes to hydraulics, which limits my ability to make any sort of
decision.

At the ABS school, there is a press made by Uncle Al of Riverside
Machine (http://www.riversidemachine.net/item16342.ctlg). The two
features that seemed important were 1) it would accept interchangeable
dies and 2) the foot pedal would lower the press at a constant speed,
it would hold at a certain level, or if you took your foot off it
would raise up.

I was with MS Chris Marks (http://www.marksforge.com/) when he used
this press to create a demo billet of damascus and remember him saying
it wasn't strong enough. I believe his press was closer to 50 tons.

Anyway, this brings me to my question. Does anyone have any
experience with or opinions on the Harbor Freight 50 Ton press found
he
http://www.harborfreight.com/cpi/cta...emnumber=46768

My thoughts, questions and observations:
- What powers this press? Can you just hook up a compressor? I have
a 5hp / 60 gal / 13.3 cfm @90 psi unit. Would that work?
- How would one convert the unit to be foot pedal operated?
- It looks like one would have to raise the bottom table up quite
high to use this press on a billet of steel that was only 2-4" tall.
- The manual says that you basically use the air supply to lower the
ram to the material and then pump it by hand. Can't you just keep
using the air pressure to ram into the material? Or does it lack
sufficient force in that manner?
- It looks like it would be difficult to fit dies onto this unit.

I'm only aware of two commercially available presses. Uncle Al's, and
the one from Carolina Knives.
(http://www.carolinaknives.com/press/press.html) If anyone knows of
others I would appreciate a reference.

Finally, would I be able to build my own press using the $70 HF 20 ton
bottle jack discussed in the other recent thread? I am a good welder
and a reasonable metal worker and handy sort of guy in general. I
just don't know anything about hydraulics...

Thanks in advance,

John P.

Steve Smith wrote:

As I commented to the other Pete, I don't know a thing about
air/hydraulic. How come the instructions recommend squeezing the air
valve and pumping the handle at the same time? Hopefully you don't have
to rub your tummy too.

The instructions are a bit hinky. With the release valve at the front
closed, applying air (squeezing the air valve) will cause the press jack
to raise (press to lower if in a press). You release the air valve to
stop the jack.

In the case of a press you might want to use air to bring the press to
the contact point and then manually pump the press so you can operate
more slowly and have a better feel if you're pressing an expensive
bearing. If you're doing something less precise then operating on air
alone is fine.

Another trick if you add some sort of handle to the release valve (I
just hacked an old screwdriver handle to fit) is that you can leave the
air valve in the locked on position and control the press entirely from
the release valve. It uses a lot of air and is a bit noisy, but when the
release valve is open the pump will just circulate the oil and the
return springs will retract the press. Close the valve and it goes down,
open it and it goes up.


Noisy? Sounds like my press...

Probably comparable overall. A hydraulic power unit will be a constant
whirring, where the air/hyd jack is a rapid put-put-put when it's in
action.


So the air/hydraulic uses air to turn a hydraulic pump?

Not turn, cycle, it uses a piston pump (reciprocating) just like the
manually operated piston pump. In fact if you're impatient you can pump
the manual handle while the air is running and move the jack faster.
Overall speed is probably along the lines of 1/4" / second which is fine
for general pressing, but probably slow for the forging application.

Pete C.

On Sat, 31 Dec 2005 15:47:27 GMT, "Pete C."
wrote:

I disagree, the commercially available 20T H presses are quite
inexpensive and will save a lot of time and effort tracking down the
steel, welding and trying to keep things square. My recommendation would
be to use a commercial 20T press frame as a starting point. The 20T jack
can readily be used separately as a normal jack.

You should be able to find a suitable hydraulic cylinder, valves and
pump unit from a place like http://www.surpluscenter.com and have a fast
powered unit operating in short order.

Thanks for jumping in Pete. Let me see if I understand correctly:

If I were to purchase, from Harbor Freight, the 20T Air / Hydraulic
Bottle Jack (Item 41487) along with the 20T Shop Press (Item 32879), I
could replace the stock manual bottle jack with the Air / Hydraulic
bottle jack to more or less duplicate your machine?

And all I would need to do is hook it to a sufficient air source for
power? Would a 13.3 CFM @90 PSI compressor do the job?

Also, being a complete newbie at anything air or hydraulic related I
am not following along very well with how you created the foot pedal
or the use of the Bimba. Could you attempt to explain exactly what is
going on with the control unit?

Assuming the press will work for Damascus, even if it isn't ideal, I
will purchase the components and fabricate it. I'll even document the
process for everyone's benefit. But I'll definitely need a little
more information / guidance on the foot pedal stuff.

Thanks,

John P.

"John P." wrote:

On Sat, 31 Dec 2005 15:47:27 GMT, "Pete C."
wrote:

I disagree, the commercially available 20T H presses are quite
inexpensive and will save a lot of time and effort tracking down the
steel, welding and trying to keep things square. My recommendation would
be to use a commercial 20T press frame as a starting point. The 20T jack
can readily be used separately as a normal jack.

You should be able to find a suitable hydraulic cylinder, valves and
pump unit from a place like http://www.surpluscenter.com and have a fast
powered unit operating in short order.

Thanks for jumping in Pete. Let me see if I understand correctly:

If I were to purchase, from Harbor Freight, the 20T Air / Hydraulic
Bottle Jack (Item 41487) along with the 20T Shop Press (Item 32879), I
could replace the stock manual bottle jack with the Air / Hydraulic
bottle jack to more or less duplicate your machine?

And all I would need to do is hook it to a sufficient air source for
power? Would a 13.3 CFM @90 PSI compressor do the job?

Also, being a complete newbie at anything air or hydraulic related I
am not following along very well with how you created the foot pedal
or the use of the Bimba. Could you attempt to explain exactly what is
going on with the control unit?

Assuming the press will work for Damascus, even if it isn't ideal, I
will purchase the components and fabricate it. I'll even document the
process for everyone's benefit. But I'll definitely need a little
more information / guidance on the foot pedal stuff.

Thanks,

John P.

It was a different Pete that posted about the foot pedal and air
cylinder operated release valve. I believe he posted a link to some
pics. As for the basic press, the 20T air/hyd jack will just swap in
place of the 20T manual/hyd jack that comes with the press.

90 PSI probably won't make the full 20T, but it should produce close to
it. I think you need close to the 120psi max in order to reach the
relief valve limit. Easy enough to test, just stack a couple solid press
plates and press on them. If the air pump stops cycling then you haven't
reached full pressure, increase air pressure until the pump keeps
cycling and you've reached the hydraulic relief valve setting.

If you need a faster full hydraulic powered press you can still take the
basic 20T H press as a starting point. Remove (or don't install) the 20T
jack. The top frame will be two "C" channels with a gap between and a
heavy plate welded on the bottom.

Find a front mount ~10" stroke hydraulic cylinder that will fit the gap
between the "C" channels. Drill the appropriate holes in the heavy plate
to mount the hydraulic cylinder from the top with the ram pointing down.
Where the ram touches the upper press plate where the original jack
would sit, weld a piece of steel pipe to act as a receiver for the ram
so it can't slip to the side.

After the cylinder is mounted it's simply a matter of connecting a
hydraulic power pack and valve to complete the press. The GPM flow rate
of the hydraulic power unit will determine the press speed. A power unit
with a two-stage pump will provide a faster closing speed followed by a
slower pressing speed. Valving can be anything from a basic lever
actuated valve, to a rocker foot pedal, to a solenoid valve and hand
button pendant.

The ultimate pressing force will be determined by the hydraulic cylinder
bore and the max PSI of the power unit. 2,200 PSI or so would be typical
for a setup like this. If the cylinder that will fit between the
channels does not have a large enough bore, you could use a larger one
with a longer stroke that can mount above the channels and use longer
grade 8 bolts to fasten it to the bottom plate.

Either way, starting with the commercial 20T press for the $200-$300
will save you a lot of work.

Pete C.

Thanks, much clearer.

Steve

Pete C. wrote:

Steve Smith wrote:


As I commented to the other Pete, I don't know a thing about
air/hydraulic. How come the instructions recommend squeezing the air
valve and pumping the handle at the same time? Hopefully you don't have
to rub your tummy too.



The instructions are a bit hinky. With the release valve at the front
closed, applying air (squeezing the air valve) will cause the press jack
to raise (press to lower if in a press). You release the air valve to
stop the jack.

In the case of a press you might want to use air to bring the press to
the contact point and then manually pump the press so you can operate
more slowly and have a better feel if you're pressing an expensive
bearing. If you're doing something less precise then operating on air
alone is fine.

Another trick if you add some sort of handle to the release valve (I
just hacked an old screwdriver handle to fit) is that you can leave the
air valve in the locked on position and control the press entirely from
the release valve. It uses a lot of air and is a bit noisy, but when the
release valve is open the pump will just circulate the oil and the
return springs will retract the press. Close the valve and it goes down,
open it and it goes up.



Noisy? Sounds like my press...



Probably comparable overall. A hydraulic power unit will be a constant
whirring, where the air/hyd jack is a rapid put-put-put when it's in
action.



So the air/hydraulic uses air to turn a hydraulic pump?



Not turn, cycle, it uses a piston pump (reciprocating) just like the
manually operated piston pump. In fact if you're impatient you can pump
the manual handle while the air is running and move the jack faster.
Overall speed is probably along the lines of 1/4" / second which is fine
for general pressing, but probably slow for the forging application.

Pete C.