SAMA Export back on the workbench - Page 2

[SJM]

Don't know the diameter of the piston but MAYBE this would work? http://www.daf.com/daftrpcatalogus/en/-165381.htm

The size 0 compressor works within the 40-75mm range. You'd still need your wooden dowel to do the push, but the compressor would POSSIBLY keep the gaskets/seals in place?!?

Whoa, I can't tell for sure from the picture, but is that going to work like the miniature bottle jack that Timo was suggesting way back in a previous thread, maybe about La Peppina?

Hmmm....I'll check into it.
Thanks for the good ideas.

Susan

[ntwkgestapo]

Yeah, it's a "tiny" piston ring compressor, used to compress piston rings so the piston with the rings on it can be inserted in the cylinder. I'd recommend you lubricate the compressor AND the seals with a bit of olive oil or PURE mineral oil (and truly pure mineral oil is a bit hard to procure... maybe the pharmacist?) then compress the seals such that the compressor is just a tad larger than the cylinder and press the piston assy in with your dowel and lever... NO guarantees this would work, but it MIGHT! The problem is in finding a compressor that's SMALL enough! Don't know the cost, but it shouldn't be much. Most piston ring compressors are $10-$20 max and many are $5-$7... Hope this helps!

[SJM]

Yeah, it's a "tiny" piston ring compressor, used to compress piston rings so the piston with the rings on it can be inserted in the cylinder. I'd recommend you lubricate the compressor AND the seals with a bit of olive oil or PURE mineral oil (and truly pure mineral oil is a bit hard to procure... maybe the pharmacist?) then compress the seals such that the compressor is just a tad larger than the cylinder and press the piston assy in with your dowel and lever... NO guarantees this would work, but it MIGHT! The problem is in finding a compressor that's SMALL enough! Don't know the cost, but it shouldn't be much. Most piston ring compressors are $10-$20 max and many are $5-$7... Hope this helps!

Thanks. I was just looking up piston ring compressors and getting a better idea of how they work. From the picture I had thought it was going to be how I pumped the piston up into the bell. Now I see that I had that part wrong, but it might still help with getting the piston back into the bell again...

Ideas are gems.
Susan

[Bushrod]

To pull an idea from my two stroke Italian scooter days, can you chamfer the area where the piston goes in? See the picture. It will compress the seal as it pushes in.

Had a devil of a time fitting a new piston on a bike that I had bored out. Turns out the shop didn't chamfer it at all. I was able to do it with a hand file.

[ntwkgestapo]

Thanks. I was just looking up piston ring compressors and getting a better idea of how they work. From the picture I had thought it was going to be how I pumped the piston up into the bell. Now I see that I had that part wrong, but it might still help with getting the piston back into the bell again...

Ideas are gems.
Susan

Yeah, with engine pistons (and the rings! ) you put the rings on the piston, put the piston in the compressor, crank the compressor down such that the INSIDE of the compressor is the same size as the cylinder you're inserting the piston into (doesn't hurt to have it a 10 thousandth smaller!) and then, literally, pound the piston down into the cylinder (often using a block of wood and a hefty hammer! ). similar action with this, only I'd be concerned with compressing it too far as that might injure the seals!

Edit: Gently, Gently! I usually just tap the piston in using a "dowel" (usually turned down from a 4x4 or something) and a "recoilless" hammer...

[narc]

sciencelab.com stocks a laboratory scissor jack. 6" x 6" , minimum ht 3", maximum ht ~10", 200 lb capacity. Not sure if this scissor jack would work in place of a C-clamp. Cost is relatively high for a very limited use tool. Somewhere there must be a mini scissor jack similar to what you find in most autos that is relatively inexpensive. Time to google.....

Regarding the piston gaskets. Would a hose clamp work in slightly compressing the gasket allowing it to be worked into the piston housing?

[espressme]

Hi Sue,
Hope the thumb is better!
Did this once't or more times!:) Makes a good stable clamp!

Requires only hardware store stuff and a buddy with a saw, 1/4" drill motor and spade drill bits,
Size it to suit the machine you are working on. Cost ~$5 US. Made from ~ 1/2" threaded rod, 4 washers, nuts and 3/4" plywood scrap.
Hole in top board center made to fit top assembly and/or a couple of pieces of scrap glued to locate the group top , hole in bottom showing where to put piston pusher of whatever kind.
Put in place on the machine and tighten the nuts evenly on each side till assembly is compressed and then do what a gal's gotta do!
Have fun
Richard

[peacecup]

Right Richard, that's what I've been thinking. Very stable and easily adjustable. Susan should be smelling the coffee now....

[mousetail]

Meanwhile, if anyone has any ideas for that special rig, send them my way. I'm going to try to go at this more safely and scientifically this time.

Sue, I managed the job on my Lusso with both thumbs intact. Have a look at...

http://www.home-barista.com/forum...591-120.html#44439

With the driptray removed, and the machine on the edge of the bench, it is possible to use the fixed jaw of this clamp on the top of the group and the adjustable jaw on the piston. That removes the need for intervening washers, bits of wood &c and makes the whole thing more secure and much less threat to the opposable digits.

Best of luck
Bob