Hydraulic powerpacks, questions

JTknives

JTknives

Blade Heat Treating www.jarodtodd.com
Knifemaker / Craftsman / Service Provider
Joined
Jun 11, 2006
Messages
8,633
Does any one know anything about Hydraulic powerpacks. the surplus store i go to has one of these i think. last time i was there (last saterday) i was looking at there motors and saw a motor that looked like it had a round tank attached to the end where the shaft was. i did not know what it was so i was like hu dont know what that is. but today i was looking at the surplus center site and it looks like there ac Hydraulic powerpacks thay have for sale. I'm going to be heading back up there today after work to get a forge blower they had for cheep and also look at the pump. they also have rams and hoses. everything i need to build a Hydraulic forging press. i have wanted one of these and if it is a pump and its good i dont think i could pass it up as it would most likley cost under one hundred bucks. so what should i look for to tell if it has the power i need.
 
JT, I have one of those with a square tank. Came off a car lift. Still haven't done the research to build the press. It would be nice if someone would post a "How to build a press tutorial" IG would be a good canidate for that::D
 
I am in same position that you are in, wanting a press, but not building it yet.

I have done a bunch of research though.

recommended specs include AT LEAST 24 tons
stroke speed of AT LEAST 1 or 2 inches per second

Assume 2500 psi
assume 5 inch cylinder, double acting


Pressure
cylinder area x pressure = total press pressure
pi x radius of the cylinder ram squared
radius is half of diameter

3.14 x ((2.5) x (2.5)) square inches x 2500 Pounds per square inch fluid pressure
=19.625 x 2500
=49 063 pounds

diveded by 2000 pounds per ton
=24 tons

increasing either cylinder diameter, or pressure will increase total pressing tonnage
increasing pressure requires higher proof hoses, valves, fittings practical limits 2000, 2500, 3000
increasing cylinder diameter will require a larger pumping volume, or will decrease stroke speed


Stroke speed
cylinder volume = cylinder area (from above) x cylinder stroke length per inch
=19.625 square inches x 1 inch
= 19.6 cubic inches per second for 1 inch per second ram speed
or
39.2 cubic inches per second for 2 inch per second ram speed


Pump Volume
approx 20 to 40 cubic inches per second
converted to gallons per minute
1 us gallon = 231 cubic inches
20 cubic inches per second x 60 seconds per minute / 231 cubic inches per gallon

5.2 gallons per minute at 1" per second ram speed
to
10.4 gallons per minute at 2" per second ram speed


Motor horsepower

BIG
5 HP ???
3200 RPM Pump specs are usually based on a high speed motor
let somebody else calculate this based on the pump size and pressure
motor size guidelines are often given with pump specs
Hp to drive hydraulic pump = Psi x GPM / 1714
2500 x 10 / 1714
= 14.6 HP ???
but our speed at high pressure is much lower...
I have read 5 hp is reasonable
let experience solve that one...who knows the answer?


I am leaning toward a 6 inch cylinder and a 10GPM pump
6 inch cylinder at 2500 = 35 tons
1.3 inch per second stroke speed.
5 HP motor
10 gallon tank

That parts list that Indian George posted kinda works out to the same numbers...

Reservoir ?
1 gallon per GPM pump capacity = 10 gallons


after i did all that....i found a webpage that has online calculators
Damn!

http://www.surpluscenter.com/Hydraulic.htm


SO...Is this reasonable ???????????????????????????????????????????????/

I really would like a copy of Jim Baston's book to see if i am missing anything
 
Steve -Those numbers are on target.

JT - The Hydraulic power packs and tank/motor units are usually not big enough for running a press.Take a look at the motor size and the GPM of the pump. Depending on how big a press you want it takes a big motor and a large volume pump.
For a basic description, you want a press that delivers over 20 tons . The practical minimums are : a 3-5HP electric motor ( or 7-10 HP gas), at least an 11 GPM two stage pump, 10 gallon tank,and a 4-5" ram. The whole thing has to be built heavy. 20+ tons of force will twist and bend steel easily. Use I-beams and plenty of 3/4-1" steel. Dies and anvil plates have to be heavy, too. I would suggest that you use 1" plate for all tooling.

Jim Batson's book, "Build your own hydraulic forging press", is a wealth of information and part numbers. His plans are straightforward and fairly easy to understand. You can get it on Ebay or from the ABS (and other sources).I would suggest anyone who plans to build a press have this as a reference. The tables and charts alone are worth the price. No one likes to do hydraulic math. The other plus is that this book was written with the specific intent of using the resultant device for forging and knife making. The necessary parameters have been considered by Jim Batson, who is a rocket scientist (NADA) and engineer.

Stacy
 
This thread, http://www.bladeforums.com/forums/showthread.php?t=598323, has info on sourcing Batson's book, as well as Indian George's shopping list.

Fellow forumite, Rob Johnson, just lent me Batson's book. I'm quite excited, even though it will take a long time to source and afford all the stuff to build one. Reading it through is more fun than porn! Steve all your numbers look spot on. I figured you had the book. If you reasoned that all through sounds like you'll have little trouble.

I am wondering about Batson's H frame press. Has anyone round these parts built one? How's it working for you? Is 22 tons enough working force for you? How do you like the die pushing up from the bottom? Considering my suburban scene now, I especially like its reasonably light weight (500 lbs), small size and movability/transportability.
 
I built the Batson H frame and it works great.

Northern Hydraulic has all you need.

16 GPM pump
5 hp Leeson motor
log splitter control valve
5"x12" cylinder
10 gal oil tank
filter and hoses

But like Stacy said, get Batson's book first!
 
Northern Tools should just make a "build yer forgin press package" ;)

There's a really neat thread on Fogg's site about building a "tabletop" press with a 20 ton air over hydraulic jack from HF.
 
Will Leavitt said:
There's a really neat thread on Fogg's site about building a "tabletop" press with a 20 ton air over hydraulic jack from HF.
Click to expand...

I built one of those table top presses using a 20 ton air over hydraulic Jack from HF. Just drew out a 1" slice of 2" W2 from Don Hanson last weekend with it. Worked great. Took about 5 heats to get a 1/4" X 1 1/4" X 8" billet.

My camera broke so no current pics but here is a pic of when I was 3/4 of the way through building it. Had scrap steel already and jack cost $70. Not like a big press but cannot beat it for under $100. Takes up 1' X 1' floor space in my shop. Flat dies are 2" X 1.5". Drawing dies are 2" X 3/4". Rigged the activation switch into a foot pedal by just screwing it onto a piece of 1" X 6" X 8" piece of wood. Yeah, pretty getto but it works...

PressBuild001.jpg


Eric
 
Ya i had been thinking about building one of thoes but i did not know how well it worked. also has any one used the 50 ton air jack, would it be to slow. or could you use 2 20 ton jacks side by side for a total of 40 tons.
 
JTknives said:
Ya i had been thinking about building one of thoes but i did not know how well it worked. also has any one used the 50 ton air jack, would it be to slow. or could you use 2 20 ton jacks side by side for a total of 40 tons.
Click to expand...

Speed is not ideal but I see this as a stepping stone to having a real press. Need more room in the shop before I can do that though. At this time I am willing to put up with its slower speed as long as it gets the job done for what I need to do and it does... Just make sure the distance between the dies are very close to the steel size you are putting into it before pulling out of the forge.

Some day I'll get a REAL press. :p
 
I want to build one but I really need to work on my welding skills first..... would hate to be ducking hot steel and assorted press parts in my shop :eek: I guess I oould back up the welds with bolts.
 
Eric, you're making a trip down to San Diego when I'm in S CA more and more tempting. That press looks way cool!

Don, do you press up from the bottom then?
 
Great thread....
Have you guys thought about using some ideas from the jewelers press,I will try and post pictures if I cant look for Bonnie Doon Press Rio Grand sells them..On that note if you build one of these presses and later decide to get a full size one,these small presses come in handy for doing allot of different pressing operations for handle and sheath work in pressious metal along with jewelery work so dont think making one is a mistake it is just another added benefit to the shop,found bent guard material can be flattened quickly with this press.
I will be building one of these mini presses also.

9768d1227832012t-mini-hydraulic-press-110455.jpg


Bonny Doon 20-Ton Mark III Hydraulic Press


9769d1227832012t-mini-hydraulic-press-110457.jpg


Bonny Doon 20-Ton Mark III Electric Hydraulic Press


9770d1227832012t-mini-hydraulic-press-110462.jpg



Bonny Doon Pro 25-Ton Manual Press


And these will take the pressure.They do make a 50 ton version of the pro model and have the pro in electric....

These pics are just to give you guys other ideas on this small press,check out rio grande and see what all you can do with one.


Bruce
 
Last edited:
dont you guys love the price on these table top presses.....Ouch.....I bet we can all build them cheaper.

I like the idea of the pressure gauge on the side also.

Bruce
 
Bruce Evans said:
Great thread....
Bonnie Doon Press Rio Grand sells them

9768d1227832012t-mini-hydraulic-press-110455.jpg


Bruce
Click to expand...

I've see them and like the idea, but i think their prices are way outta line.

I've often thought...on a mini press a relatively cheap 20 ton bottle jack could be converted instead of the very high priced cylinder...heck they did it.

I like gauges too
 
Die presses don't need to be fast, and only have to press once. Those converted bottle jacks make good presses for slower ,single strike jobs - like punching guard slots and stamping tangs. They won't work for forging and shaping.
I agree that the Bonny Doon presses are ridiculously priced.
Stacy
 
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