[TheForge] Hydraulic Press

Sat Mar 19 16:46:12 EDT 2011

Start with preheating the dies.  This isn't something just for blacksmiths 
or bladesmith, it is an important part in the forging industry.  Preheat can 
be as simple as a heavy hunk of steel heated to a good red / orange heat 
held between the dies with low clamping force.  Dies at 300 F will make a 
big difference in the rate of cooling of the work piece in actual forging. 
(Works on your anvil too.)

I would not go the route of an accumulator because this is just more stored 
energy if there is a problem -- and most likely worse more stored hydraulic 
oil.

There are two great risk I see in home made hydraulic presses.  One is the 
great stored energy present in a loaded press that fails.  A huge spring 
sending metal flying all over the place.  If you have ever seen the damage 
done by the failure of some part of a crane lifting a 100 ton load you will 
understand that this can kill you several times over.  (Once is enough for 
most blacksmiths, most of us only get one life, Frosty is working on number 
2 or 3).

The second great risk is of fire from a failure in the hydraulic hose or 
pipe system on a press.  With HOT metal we always have present a way to 
light off the oil mist from a leak or hose break.  The safest presses I have 
seen are the "pull down" presses that can put all of the hydraulics below 
the work piece and can shield all of the hoses / pipe so that a leak has 
limited chance to spray oil on the hot metal.  In industrial applications a 
fire ball from a major leak has killed a number of operators and also burned 
down a number of press operations.

Dave Smucker

--------------------------------------------------
From: "peter fels" <artgawk at thegrid.net>
Sent: Saturday, March 19, 2011 4:20 PM
To: "Blacksmithing List Sponsored by ABANA" <theforge at mailman.qth.net>
Subject: Re: [TheForge] Hydraulic Press

> I'd add that 2 of the 3 100 ton hydr presses i've seen doing hot work at 
> full capacity,
> distorted alarmingly under load. Those 2 were home made by competent 
> smiths.
> Which brings me to pose a problem .
> Hydraulic presses are by nature slow. Under pressure, the dies suck the 
> heat out of hot work fast.
> How does one go about either reducing the speed of heat drain or 
> increasing the speed of die travel under load?
> A stainless or titanium die set might make a bit of difference.
> Would a large accumulator work to speed up the dies?
> Other solutions?
>
> On Mar 19, 2011, at 6:56 AM, John Allen wrote:
>
>> Talking with my engineer buddy for the nuclear plant. He told me before 
>> that
>> if you build a header for a door, if you double the width of the beam, 
>> you
>> increase the strength by 10%. If you double the height (in 1 piece of
>> course) you gain 100% more strength.
>>
>> Square / Rec Tubing is hands down the strongest steel out there. The 
>> problem
>> with it is workability. You don't build a skyscraper out of tubing 
>> because
>> you can't bolt to it, can't add sections easily, it is bulky and the cost 
>> is
>> higher to make then I beams. Now pertaining that to your frame, you would
>> need to have 6x6 x1/2" walls, but now they are 6" wide, you can use a 
>> beam
>> with similar strength and 8" tall and 5" wide. The best and worst thing 
>> with
>> commercially made stuff is that they already figure out what materials 
>> best
>> to use. Why.... because if they made things with what they want to make 
>> them
>> out of, then the competitors will use what sells by price versus what is
>> right.
>>
>> If you buy an apple from your local farmer for  50 cents and the grocery
>> store for 48 cents, everything is the same since they are both big, 
>> juicy,
>> and red right? Well that one from the store could be from South America 
>> and
>> was picked early to ripen on the truck up here, and sprayed with 
>> chemicals
>> that the US has banned. Well, that just says never take any shortcuts in
>> especially things that could go wrong.
>>
>> -- 
>> John Allen
>> Country Metals, LLC
>> (856) 542-4316 (cell)
>> (856) 504-0087 (fax)
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