Cobalt

[sam_smith]

Re: Cobalt

Looking really good mate, that's the best quality hydraulic ram I've seen built! What wall thickness did you go for on the ram?

4 tons will be a good test for the chassis

[Kenny]

Re: Cobalt

Looking really good mate, that's the best quality hydraulic ram I've seen built! What wall thickness did you go for on the ram?

4 tons will be a good test for the chassis

Thanks mate, 6mm wall , may put the ram in this chassis and film it for a laugh to watch the front snap off

[calumco]

Re: Cobalt

looks mint! whats the distance from the front of the bottom jaw to the back of it where it meets the claws pivot point roughly?

[sam_smith]

Re: Cobalt

Good choice... so you could easily run that ram to 4000 psi if you wanted to in the future.

Lol, I remember writing off a couple of the early Tiberius chassis's... wish i'd thought to video them.

[Gasbot]

Re: Cobalt

Don't want to flame anything, but assuming 3000psi, 2 I/D, 6mm wall, and depending on the grade of Ti used, your ram could be borderline from a pressure point of view. Looking at the picture posted, I'd guess that the tapped holes are reducing the 6mm wall too?

Not poo-poo-ing anything, just want to say be careful - especially if its Ti Gr2.

Nice looking bit of kit though.

[Kenny]

Re: Cobalt

Don't want to flame anything, but assuming 3000psi, 2 I/D, 6mm wall, and depending on the grade of Ti used, your ram could be borderline from a pressure point of view. Looking at the picture posted, I'd guess that the tapped holes are reducing the 6mm wall too?

Not poo-poo-ing anything, just want to say be careful - especially if its Ti Gr2.

Nice looking bit of kit though.

6AL-4V Titanium , ( Grade 5 )

[Gasbot]

Re: Cobalt

Cool, just keep the minimum shell at/above 4mm around the threaded holes - obviously thicker is better though. Just as a comparison if it were Ti Gr2 you'd be looking at over 9mm - although these values are for cylinders and not a flat plates.

Gotta love Ti Gr5!

[sam_smith]

Re: Cobalt

Cool, just keep the minimum shell at/above 4mm around the threaded holes - obviously thicker is better though. Just as a comparison if it were Ti Gr2 you'd be looking at over 9mm - although these values are for cylinders and not a flat plates.

Gotta love Ti Gr5!

9mm wall thickness with grade 2 ti on a 50mm ram to 3000psi!?? I'm curious, how did you work that out??

Of the shelf steel rams with 2 inch bore often have a 5mm wall rated for 3000 psi safe working pressure (with significant safety factor). The steel is nothing special, probably ~ 300 MPa Yield Strength which is comparable to a reasonable Gr 2 ti.

[PJ-27]

Re: Cobalt

€€Meanwhile in camp Bitza€€

Hey Dan, shall we use this oven shelf or the side of that dishwasher for metal?.................

[Eventorizon]

Re: Cobalt

€€Meanwhile in camp Bitza€€

Hey Dan, shall we use this oven shelf or the side of that dishwasher for metal?.................

We need to fit a like button just so that I can like that post Go PJ!

[Gasbot]

Re: Cobalt

Its all in Asme bpv. Carbon steel has a design stress of about 120Mpa, Ti Gr 2 is about 90ish, Ti Gr 5 is over 220 mpa - from memory though, the book is at work.

There is a specific set of formula to plug the numbers in to which spits out the minimum shell. Asme is conservative, but it is pretty much standard throughout the industry I work in. Other standards may give lower answers but they will be in the same ball park.

[maddox10]

Re: Cobalt

Funny, that reference to ASME norm.

An uncle of me worked 40 jears as piping engineer in the petrochemical industry. His explanation about the differences between DIN and ASME.
In WW II, the Germans had a lack of steel, so the engineers messured and tested, remessured and retested to see how low in the use of steel for tubes and flanges they could go.
The US on the other hand had steel coming out of the ears, so, they erred on the side of safety and easy of manufactoring, and added 1/16 here and there.

The difference. A light DIN flange for a 100mm inner diameter tube weights 3.24 kg. A simular use ASME flange for a 4 pipe weights 6.84 kg.

[daveimi]

Re: Cobalt

Have you decided how your self righter will work? I'm interested to see it for some inspiration :-)

[Kenny]

Re: Cobalt

Have you decided how your self righter will work? I'm interested to see it for some inspiration :-)

I have mate yes, i'm using a 256:1 Banebots gearbox motor combo then also using MOD1 gear with a ratio of 4:1 from the gearbox to give me a 1024:1 Ratio running a top cover over the hydraulic cylinder ( Like a neck piece ) which will pivot at the back turning it back over

[daveimi]

Re: Cobalt

Wow that sounds really good, are there any pro's to using an electric actuator? I imagine them to be slow and heavy (I mean as apposed to a gear motor setup such as yours will be).