More punching on the Hydraulic press...

[Larry L]

Well yesterday my home built press ran with its new power supply for the first time... Today I built some tool holders and a few punch tools just to see if I could indeed punch a hole in something...

Pic of the new power unit I built... 10 Hp two stage... 25 GPM up to 700 PSI then 5 GPM up to 3000

A side shot of the press...




I had pretty good results.. I had one tool that I didint normalize after welding on a set collar and it shattered.... but the other two H-13 tools made holes and held up




the wide flat chunk is 3/4 X 2 with a one inch hole... The heavy chunk under it is 2" square with a 1 1/4 X 1/2 hole.... the smallest one on top is 1" sq with 3/8 X 1" hole...

This is the dovetail tool holder set I made for quick change tooling..







I need to work on a bolster and stripper plate... the bottom table unbolts from the machine so I can change out lowers for diffrent tooling...

[Grant]

Wow! That looks like way more fun than I'm allowed on a school night. Pretty cool sorta dovetail holder there Mr. Langdon! You're half-way there when ya spend every waking moment thinking about this stuff.

Holy Crap! I just noticed you're pushing 25GPM through those pissy little hoses AND undersize quick-connects? You have any idea what 25 gallons per minute looks like? Well, take your home garden hose, full blast mine will fill a 5 gallon bucket in about a minute. Now times that by five!

[Larry L]

Those are 3/4 disconnects and 3/4 hose... both rated to flow 36 GPM....

[Grant]

Be fun to hook a pressure gauge at the pump to see how much pressure it takes just to push that fluid through the plumbing.

[Larry L]

well the gauge on the cylinder reads about 50 psi running it in air.... it cant be much more than that can it? its got to take more effort to move the ram than just the oil?

[Larry L]

So David.... When you punch do you make your first go on solid backing and then when you flip go to a bolster? Do you size the bolster with much clearance? If you had to redo your stripper would you do it any diffrent?

[david hyde]

Good stuff Larry, I like the dovetail quick change stuff.

Isn't punching with a press a joy to do.

My cylinder on my homebrewed 15T has a large threaded end which is a ball ache for changing tools over but good for holding the punch/drift when pulling it out of a hole. If I were to start from from a blank sheet of paper I would make all my punch tooling quick change as per steelworker tooling (I think you guys call them ironworkers). Two flanges opposite each other and 90 degree turn to lock.

My stripper is kinda universal in that the hole will allow a wide range of puch shapes to pass throgh it. It doesn't take much tonnage to pull the punch out if it's well lubed. Haven't felt the need to change it yet.

If you look at the picture you'll see the bolster plate slides. I can either use it with no hole (solid bolster) or slide it to use with a suitable bolster hole hole. I prefer to have as little clearnce between the hole and the "final size section" of the punch, say 1mm. Kinda works for me

My punching sequence varies depending on the work, but here is a typical sequence.

1. Start with solid bolster and punch until tip of punch is almost all the way through around 3mm from bolster (using kiss blocks to let me know how near I am) TAKE CARE NOT TO GO TO FAR, IT'S THE EASIEST WAY TO WRECK A PUNCH

2. Flip the work over. STILL USE solid bolster and kiss block to take punch to about 3mm from bolster

3. back out punch slight so it is not in contact with heat of the work and slide the bolster so the hole is now under the punch. Go through with punch so it is about 1" through the work.

4. Flip over and go about 2" through

5. Flip over and go full way.

6. (optional) allow work to cool to red. Flip over and go through full way again. The cooler the work is, and the hotter (within reason) the drift part of the punch, the less shrinkage there is to the hole as it cools.

[Robert Suter]

Larry,
That is a nice set up, I wish I had one, heck I need one. Wow I know little about hydraulics but 50lbs to move a ram with that much volume seems high. Is there a restriction between the gauge and ram or is that a ‘normal’ pressure for a ram of that volume at that velocity?
Bob

[Grant]

Sorry Larry, looked smaller in the photos. Still at the top end (IMHO) and those quick connects do restrict. But if it's working good no reason to worry. Looking good, my man.

[Ries]

Grant- why is your dog suddenly wearing a blue sweater?
Did somebody have a birthday, or is it just fall already?