Small Hydraulic Press Tools

I have been wondering about building something like this: **LINK**

https://www.riogrande.com/landing/bonnydoon

and have found several DIY options including this one: **LINK**

https://www.rcgroups.com/forums/showthread.php?3944399-2-Ton-Press-Brake-DIY

… which includes a surprising amount of plywood in its construction.

I only want a small bench-top machine, and would be using a ‘2-ton’ hydraulic jack

Does anyone have a recommended design, or should I just ‘reverse engineer’ the Bonny Doon , and scale-down accordingly ?

MichaelG.

Edited By Michael Gilligan on 03/10/2021 10:31:20

Too late to edit, but the introductory video for Bonny Doon is worth a look: **LINK**

https://youtu.be/ztUcvSX-Apg

MichaelG.

Michael, I have also been thinking about a press; I bought a 2 ton jack just before lockdown.

The option you linked has surprisingly small 1/4 inch screws, in shear and in plywood, but clearly it works for the example shown. I wonder what force was necessary for the bends shown.

I have seen examples that use large diameter studding in tension, which avoids welding, and I will probably use that method. I want to try pressing small sheet metal parts - not planning on coining, which requires much higher pressures!

Bill

Pressures of 10,000psi are not uncommon in hydraulics on small hand powered equipment. So generating a force of even 50tons whilst slow is possible, even easy ! One very useful addition to any hydraulic gear is a pressure gauge tapped into the cylinder feed, this will give you an idea for the applied force and make repeating the task easy. I'm supprised that hydraulics are not mentioned on here more often as the principles are simple and can be put to many applications.

The idea of hiding the return springs in the box section side tubes is neat. Using double acting rams one can avoid the need for the springs and also then use the "press" to pull, though with a slightly lesser force. Then there is the hollow cylinder, very useful. Noel.

The electric pump is a huge time saver and lets you focus on the job

If one is going down the route of power operated hydraulics then the following calculations are worth remembering !

Sorry it is imperial units ! 1ImpGallon = 4.55L 1Hp = 746Watts, A cubic foot is 6.25 imp gallons

Having a 10cc pump, a 4" diameter pistoned ram with a 28" stroke, an 11Kw 3Ph motor and a honda 12Hp engine, will it work and what will it do ?

Pumps are usually rated in cc per revolution eg 10cc x 2850rpm = 28500/1000 = 28.5/4.55 = 6.26 gal per min

Flow in ImpGals per min x pressure in psi/ 1428 = Hp needed eg 6.26 x 2500 / 1428 = 11 Hp

psi x piston area in Sq inch/ 2240 = tons force eg 2500 x 12.57" / 2240 = 14 Tons This is the extention force, the retraction force will be lower by the area of the piston rod.

piston area x stroke = swept volume- SV SV/ delivery = speed of operation. So 12.57" x 28" = 352 Cu "/ 1728Cu" = 60sec /4.9= 12 seconds for full stroke.

Some figures have been rounded for simplicity..

The above figures were used to show that using the ram and pump, both the electric motor or the honda engine would power the unit giving a force of 14 tons and that its operating speed would be good at 12" travel in 5 seconds. What was it ? A log splitter. Noel.

Here is another lockdown project made from scrap. The return force is by loops cut from car inner tube.

Thanks for the helpful replies

Questions for Noel, if I may:

0 - 10,000 psi seems a pretty wide range

(a) Can you recommend a suitable gauge, and

(b) Do you think that my little Hilka 2-ton bottle jack is actually likely to see such pressures ?

I understand the principle, but your numbers do seem rather extreme

... am I missing an important point ?

MichaelG.

It would be possible to do some fag packet calculations. If you know the diameter of the jack ram, you know its area. With the 2-ton on that area, you have a pressure. The same pressure will be on the pump ram and the mechanical advantage of the operating lever can tell you how much force you need to push on it. Vertical movement of main ram will give you a volume that the pump ram has to move. Vertical movement of the pump ram will tell you how much volume per stroke and thus how many strokes from closed to open. Pick a speed at which you want it to operate (e.g. closed to open in 30 seconds) and you get a flow rate.

2 ton fly press anyone?

Hi Michael,The numbers used were only because they were in my head and were a real example, though bigger than what you had in mind. A 2 ton jack should raise 2 tons force. Just for fun you could measure the piston dia and ram dia you could work out the force on the piston required to give 4480Lb of force, or wether it really gives 2 tons.

Eg, 8mm piston and 25mm ram =3.12 hydraulic advantage, taking a mechanical advantage of 20/1 will require 72Lb on the lever to lift 2tons.

I have a Tangeye 10 ton cylinder with a 1.5" piston, this will require 9500psi !

0 to 10,000psi gauge 4"dia new at a local supplier £100, or the auction site, much cheaper or second hand.

Hope that helps, Noel

My first one was made from box section, (which had once been the legs of a semi trailer  ) , powered by a 6 ton hydraulic jack.

I now use an ex materials laboratory specimen press, which has a 5 ton jack. The side standards are 1" round bar.

Only defect is since replacing the seals, the ram and moving platen have to be forced down by hand rather than gravity, but it leaks less oil, now!

Not often needed, but invaluable when it is

Howard  (Emojis - GRRRR   Its done it again! )

Edited By Howard Lewis on 03/10/2021 16:44:53

Edited By Howard Lewis on 03/10/2021 16:45:45

.

Thanks, Noel

£100 for a gauge seems a tad pricey when I only paid a fiver for the [new in box] jack at the Charity Shop.

Probably won’t bother dismantling it to check the diameters either, but I get the idea.

MichaelG.

Exploded view might be useful for reference

[ in case it explodes ]

MichaelG.

.

looked on the auction site and £21 or so ! N

This looks easy to scale down and make as bench press. It also has the workpiece at the bottom ,safer in my opinion .Looks like it can be made without welding.

Maurice

If you want a really safe one it looks like a couple of 1 inch plates in parallel are preferred

The downside being no envelope adjustment

Edited By Ady1 on 03/10/2021 19:00:05

I have been thinking about making one of these as well. I do have on of the metalcraft manual benders but its not really for things like 25x6mm flat bar.

Hi, I've had in mind of making a press and have some material waiting, it will be a fair bit larger than what MichealG is looking for and will be of the conventional design of what is often termed as "Garage" equipment. Hopefully I can make it to use my Europress ram and pump or a bottle jack. Don't really know the tonnage of my Europress, but the hydraulics pump up to a maximum of 700 Bar and it is stronger than my 12Tonne bottle jack. I have made a hash-up press using my Europress, fish plates from railway lines and 24mm threaded rod and in the photo below, it was used to straighten out distortion on a 70 x 20mm flat bar, which was caused by welding and took no real effort on the pump handle, in fact I had to be careful that I didn't over do it, but it doesn't pump very fast, it is one of those types with a hollow ram.

Regards Nick.

Me too I discovered that I could buy the standard car engine hoist ram for not a lot.

It has a 19.5" stroke for broaches and supposedly delivers 8 tons.

Take that with a pinch of salt, but as my personal taste in broaches are all rated <2 tons it matters not.

I very nearly finished it but then I blew my CNC software and everything stopped