[TheForge] Hydraulic Forging Press
Cameron Stoker
[email protected]
Tue Apr 15 23:57:03 2003
It seems that additional force makes a press more versatile in the long=20=
run.
I've only done a little cold punching, but I'd like to make a set of=20
sheering dies and I think this is one area where force is important. If=20=
I recall, the force per area to deform hot steel is approximately 4=20
t.p.i. (tons per square inch) so pick a size for your dies and get a=20
matching cylinder:)
You can always set the relief valve to a lower pressure to limit the=20
maximum force of a large cylinder (and reduce pump wear & heat).
Running at 1800 rpm seems like a good idea to prolong the pump, and to=20=
reduce the noise.
Maybe I'm always in a hurry, but that speed seems a little bit slow to=20=
me. My press runs on a 16gpm pump at 3600 rpm for a speed of about=20
1.6"/sec. Faster squeezes cool the work less.
You don't really notice the slow speed because whenever you are=20
squeezing something that makes the pump 'kick down' to low flow all=20
your attention is on what you're squeezing.
The only things I've run into where more force would be useful are for=20=
cold bending steel and for forging Ti. My press maxes out at bending=20
2-3/4" by 3/4" a36 bar the _hard_ way between 10" centers of a three=20
point bending die.
The largest hot forging I have done in the press was some upsetting of=20=
2" square to make a post vice jaw. The press could do it without=20
problem, but keeping the bar straight took significant effort.
Forging chunks of titanium is quite tricky, and the rate it cools at is=20=
just wrong.
On and off I've been building a battlebot and last summer I forged some=20=
boeing surplus ti scraps into a set of pincer jaws. Started with two=20
4x2x6 blocks and squeezed them out to an approximate triangle 1 x 8 x=20
13. Hot working ti is tricky for three reasons, you have to keep it=20
doused in flux to keep the oxygen away and the borax makes it=20
incredibly slippery. Even at 2500, ti is still really hard and the=20
tongs don't 'bite' it at all, like they do with steel. If you try and=20
grab a tapered section, you can't squeeze too hard or the chunk will=20
'squirt' out of the tongs. It slips around on the dies just as much. I=20=
gave up on any kind of powerhammer work on ti held in tongs because it=20=
would jump out of the dies so easily.
Hand work on it is just silly. On these two pieces the edges were=20
chamfered by hand (both, really) by clamping it in the press and using=20=
an #8 sledge. You could make about 7" of 3/16" wide chamfer per heat.=20
Did I mention it cools quickly? Only got about 30 seconds of working=20
time per heat.
The one other thing that really surprised me was how easily it would=20
hot punch.
It took two days, but they were fun.
I'll see about posting some photos of this.
Sorry to derail the thread.
On Tuesday, April 15, 2003, at 08:32 PM, Ed F wrote:
> Hey Cameron,
>
> Is there any reason you'd want more snort? I have the opportunity to=20=
> make a
> press with an 8 or 10 inch cylinder and my 28 gpm pump seems to match=20=
> ok
> with either one (.7 and 1 in/sec, respectively, at 1750 rpm). The 8"=20=
> would
> be easier to squeeze into a frame and of course take less steel for =
the
> frame. What do you think?
>
> Ed
>
>
> ----- Original Message -----
> From: "Cameron Stoker" <[email protected]>
> To: <[email protected]>
> Sent: Wednesday, March 12, 2003 5:26 PM
> Subject: Re: [TheForge] Hydraulic Forging Press
>
>
>> I scaled up the principles in the batson design guide to use a 7 1/2"
>> trunion cylinder, resulting in a c-frame with about 50T force. It=20
>> will
>> out forge my #50 Little giant by a lot. It is great for heavy
>> forgings. Light forging is tricky on it because the dies cool the=20
>> work
>> much faster than a power hammer does.
>>
>>
>> I've built cold punching dies and cold chamfering dies as well. 3/4"
>> holes in 1/2" stock are easy to punch cold.
>> With 50T you can do quite a lot of forging without heating the=20
>> metal.
>> It can be particularly nice for doing chamfered square stock for
>> curtain rods - the cold working stiffens the rods quite a bit and
>> allows for longer spans with fewer brackets.
>>
>> Lately i've been doing more cold cutting and chiseling of shapes from
>> plate. Handy.
>>
>> On Wednesday, March 12, 2003, at 12:42 PM, chuck schaeffer wrote:
>>
>>> Dave,
>>> I built and used a Batson design a few years back. In fact Ric has=20=
>>> it
>>> in
>>> Sturgeion Bay with a few minor changes to it to meet his needs. It=20=
>>> is
>>> a
>>> very good design and easy to built. The only thing, it had=20
>>> limitations
>>> un
>>> what you could used for.
>>>
>>> I now build H frame units as apposed to the C frame. The H frame
>>> allows the
>>> pressure to go up by using two cylinders and still be under 3000 =
psi.
>>> The
>>> press I build now has foot control with automatic return when it
>>> reaches
>>> pressure with the option of being able to cycle it with a selected
>>> range.
>>> It develops a conservative 40 tons of force. The knifemakers at the
>>> ABANA
>>> conference used my H frame for their demos.
>>>
>>> If you would have more questions get back to me off line.
>>>
>>> Chuck
>>>
>>> Chuck Schaeffer
>>> Metals Magic Shop
>>> [email protected]
>>> Ph. 608.798.4296
>>> Fax 608.798.1940
>>>
>>>
>>> ----- Original Message -----
>>> From: "Dave Brown" <[email protected]>
>>> To: "TheForge" <[email protected]>
>>> Sent: Wednesday, March 12, 2003 12:03 PM
>>> Subject: [TheForge] Hydraulic Forging Press
>>>
>>>
>>>> I know there was a discussion about hydraulic presses a while back,
>>>> but I
>>>> wasn't interested then but I am now.
>>>>
>>>> Does anyone have any experience with the hydraulic forging press=20
>>>> that
>>>> Jim
>>>> Batson
>>>> designed? (see:
>>> http://www.artmetal.com/project/TOC/BookRevu/HydroPrs.html )
>>>>
>>>> I know our good friend and occasional poster to theforge, Chuck
>>>> Schaeffer,
>>>> has considerable experience in this area. So, any comments and/or
>>>> suggestions will be appreciated from any and all.
>>>>
>>>> Also, does anyone remember when the discussion on hydraulics took
>>>> place on
>>>> this list so I can go back to the archives and look the postings =
up?
>>>>
>>>> Dave Brown
>>>> Heritage Smithing
>>>> Green Bay, WI
>>>> ABANA, UMBA, GoM, MODA, ARG
>>>>
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>>>
>>>
>>> _______________________________________________
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>>>
>> Cameron Stoker
>> [email protected]
>> "May you run like a vicuna!"
>> pgp key @ http://keys.stoker.net
>>
>> _______________________________________________
>> http://mailman.qth.net/mailman/listinfo/theforge
>> theforge mail list group photo site is
>> http://www.photoaccess.com
>> Login: [email protected]
>> password: anvil
>> ___________
>>
>>
>>
>
> _______________________________________________
> http://mailman.qth.net/mailman/listinfo/theforge
> theforge mail list group photo site is
> http://www.photoaccess.com
> Login: [email protected]
> password: anvil
> ___________
>
>
>
Cameron Stoker
[email protected]
"May you run like a vicu=F1a!"
pgp key @ http://keys.stoker.net