The Craftmans Shop > New from Old
Re-Birth of an EPCO 60 Ton Garage Press
awemawson:
Now all that happened in 2010 / 11
So how did it turn out. Well OK'ish - it certainly pressed things, but I was never convinced that it was working correctly - I had a strong suspicion that the piston was 'letting by' and not developing the force that it should, and the end cap seals started leaking - first just a drip, but obviously getting worse week by week.
Time for a decision ! I decided a couple of weeks ago to re-build the cylinder AGAIN. I've had a bit more experience since then with hydraulics and perhaps now know more questions to ask of seal suppliers :clap:
As the cylinder is so massively heavy I decided to try and do it 'in situ' and make a 'flogging spanner' to undo and re-tighten the end cap that had given me all that bother before.
Basically this is a 6" ring spanner with lugs to engage the nut, and a flat to hammer against. I wanted to aim for a tight fit, so it could be hammered on and stay in place while being used.
This is the CAD drawing I generated to cut it on the Beaver Partsmaster:
awemawson:
I had a bit of 12 mm plate that is somewhat tougher than mild steel - no idea what it is - and it all went quite well until it broke loose from it's hold down clamps. Not a big issue as the 'overcut' didn't stop the spanner working.
awemawson:
After a bit of titivating with a file it fitted nicely - just tight enough to stay in place when tapped on with a mallet :clap:
I knew that the piston would be a bit of a pain to pull out, so I turned up a spigot (with a cross hole for pulling) to go in the hole in the end of the ram, with a recess to engage the locking bolt that holds tools on the end of the ram. Now this is where later on it turns out I made a BIG mistake. I made the spigot out of what was to hand - an old worn digger pivot pin that was 55 thou too fat, so got turned down.
Why a big mistake - because as at some point I must have pressed down with the ram, and got the spigot pressed beyond it's shoulder entering the 1.5" bore with its 1.555 diameter shoulder :bang:
It was absolutely thoroughly jammed, and not only that, managed to expand the end of the ram by 2 thou making taking off the end cap past the 'bulge' a right pain involving hydraulic pullers and much perspiration
In the end it came off - but how to remove the spigot? It became rapidly obvious that I had only one option - mount it up in the lathe, slice it off and bore it out :bang:
It's a big lump to mount - obviously had to be on a fixed steady , but then the only place I could grip it in the chuck was on the threads of the piston cap retainer - not very nice, but aluminium pads saved the threads from destruction.
In the end it proved I'd managed to press that spigot in 20 mm beyond it's shoulder - no wonder it was jammed, and says something for the power of the press that it did that when weak and in need of new seals :bugeye:
It did however mean that I had no problem using the spigot to pull the piston / ram assembly out as intended !
awemawson:
Now at last the new seal kit arrived, and sure enough they are not the same as the previous 'new seal kit' that I fitted back in 2010. The cap end was identical, but if you look at the piston, the double acting seal has a pair of nylon 'wear pads' either side. The previous lot were wider axially than the gap left when the piston end cap is fully home, so were being squashed by the cap. The latest set are the correct 1.75" wide (the others were 2") and sit snugly when the piston end cap is fully tightened and locked with it's grub screw.
I had to hone 2 thou off the outer end of the heavy chromed ram to let the cylinder end cap fit nicely. Then we were ready to push the assembly back up into the cylinder body.
Joules:
Very nice, I have some Brazil nuts I can't crack ?
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