Dake 50H Press, Rebuild? - Pins?

[dalmatiangirl61]

Made a 600 mile roundtrip run last weekend to pick up a Dake press, its a 50H with the moveable ram, price was right, could not buy the C channel to build one that cheap. It is an older unit, has a bit of a leak, and only came with 2 pins for the table that appear to be SS, and of course they are bent. I see a whole selection of alloy steels on McMaster, but only spec they give is tensile strength, no mention of shear strength. So what should I use for pins?

The press was pressed into service today for a ball joint job, but I'm unsure if its building full pressure. Pressure gauge will go to 2000psi momentarily while pumping, but quickly bleeds off to about 1200psi, and ball joint is not moving. Being that tonnage is pressure x surface area I don't know if this is correct, I suspect not.

I see Dake has a vid on YT for rebuilding the pump, but not finding anything on the ram. Has anyone here rebuilt one? Is it simple and self explanatory once you open it up, or are special tools required and watch out for launching springs and ball bearings?

 

[moonlight machine]

Made a 600 mile roundtrip run last weekend to pick up a Dake press, its a 50H with the moveable ram, price was right, could not buy the C channel to build one that cheap. It is an older unit, has a bit of a leak, and only came with 2 pins for the table that appear to be SS, and of course they are bent. I see a whole selection of alloy steels on McMaster, but only spec they give is tensile strength, no mention of shear strength. So what should I use for pins?

The press was pressed into service today for a ball joint job, but I'm unsure if its building full pressure. Pressure gauge will go to 2000psi momentarily while pumping, but quickly bleeds off to about 1200psi, and ball joint is not moving. Being that tonnage is pressure x surface area I don't know if this is correct, I suspect not.

I see Dake has a vid on YT for rebuilding the pump, but not finding anything on the ram. Has anyone here rebuilt one? Is it simple and self explanatory once you open it up, or are special tools required and watch out for launching springs and ball bearings?

Dirt simple, no special tools, no flying parts, get a kit from Dake. What diameter are the pins? I worked on one that had bent 5/8" pins. The hole in the C channel was oval, I oversized the holes and made new 3/4" dia. pins out of 4130 bar.

 

[dalmatiangirl61]

My eyecrometer says pins are 1", but will verify before ordering some round stock. There should be 4 pins, yes a few of the upper holes are slightly elongated.

 

[DanielG]

For my last similar project I used B7 rod, which is a hardened 4140. Bought it from Alro; they chopped the 12 footer into 2 pieces and UPS'ed it to me. I also looked at stressproof, but I wanted to do a QPQ-type surface finish, and the B7 was a better option for that.

If you use B7, the Niagara-Lasalle metallurgist told me there are two types, depending on whether its tempered with electricity or gas. You want, IIRC, the electric temper. You can tell by the tempering temperature. I don't recall the exact cutoff, but 1350F showed it was the correct type.

 

[moonlight machine]

My eyecrometer says pins are 1", but will verify before ordering some round stock. There should be 4 pins, yes a few of the upper holes are slightly elongated.

Your prolly right on the diameter, as I think about it the one I did was a 25 ton. It had only one pin on each side.

 

[4GSR]

Go with ETD 150 bar stock. A tad higher strength than B7 IMO. Still LaSalle made.

A rule of thumb to use for shear strength is 0.6 times ultimate yield strength or tensile of the material used. Of course, it's area times pressure=force, for your hydraulic cylinder.

Ken

 

[Garwood]

I have had 2 1" 316 stainless pins in my 40 ton press for 25 years. They look like new.

I used to use that press to deep draw 14 gauge 4130 sheet. I ripped/broke the channel on one side doing that. The pins are still nice. No bend, no marks.