I was just looking for some parts in my workshop/storage room when I spied the beat-up Technisub "Grinta" which I bought on eBay many years ago. I had dismantled it to a certain point where I could go no further and I could see where a previous owner had attacked it with a hammer trying to get the rear housing off and had also used adjustable multi-grip pliers on the rear projection of the aluminium inlet valve body. I had drilled two blind holes in it and used my special two bolt muzzle spanner to try and turn it, but with no success as the inner barrel simply turned with it while the inner barrel was locked in the lathe. Now that is really tight!
Having recently written a thread on the "Pelengas" gun which has a transverse pin holding the rear body onto the inner barrel I pulled the gun down again and instead of trying to turn the rear projection with my spanner I gave it a whack with a block of wood to loosen anything up after squirting the entire rear area liberally with WD40. To my surprise when I pushed down on the plastic rear housing with the inner barrel tube pressing hard and standing vertically on my work table the whole assembly slid rapidly down the inner barrel tube and all was revealed. Sure enough the inlet valve body is fixed with a cross-pin onto the inner barrel tube and it is double "O" ring sealed into the rear plastic housing which the rear pistol grip in turn slides over and is secured by more small pins. After that revelation the entire gun was disassembled in a couple of minutes. I found a tiny chunk of steel stuck in the inlet valve stem seal which had probably been the reason that the gun was taken out of service, where the metal fragment came from I do not know, but I think it had entered via the hand pump as it had progressed no further inside the gun.
So the only screw thread in the "Grinta" is the muzzle to inner barrel connecting thread, everything else is secured by transverse pins and if you don't know how the gun goes together then you would be hard pressed to take it apart. That included me until late yesterday!
The "Grinta" is a sort of Italian "Taimen", small air pressure tank of 30 mm OD , sleeve attachment of the rear handgrip (although the "Taimen" handle is a clamshell moulding) over a cylindrical (plastic) rear housing which forms the rear bulkhead along with the inlet valve body and is a very compact gun to look at, but it has a 13 mm ID inner barrel shooting an 8 mm spear! Too much spear and not enough gun, especially with a wet barrel.
I will take some photos of it in pieces after I clean everything up as right now it is all rather oily from my dismantling efforts and the oil that I had put in it when I last attacked it to protect the inner workings in storage. Note that even with the rear grip handle, which fits using a sleeve mounting on the end of the gun being completely removed the gun does not float despite being reduced to a long, slim cylinder. However if the alloy inner barrel was reduced in OD, it is now 17 mm, then maybe it could be made to float, but I have my doubts as the rear end still contains a lot of thick plastic and no air spaces. Its sister gun from Technisub was the "Jeans" which had a high-mounted inner barrel, it was not coaxial like that on the "Grinta", but I expect that its construction was very similar with just the end bulkheads offset upwards in their internal bores to mount the rear valve body and the nose cone higher up in the gun and thus moved off the central axis. I had seen "Jeans" in dive stores not long after they were released here, no one was really interested as the "Sten" ruled the pneumatic speargun world then and would be a much more powerful weapon than either the "Jeans" or the "Grinta", the latter model never being offered here as far as I know. I certainly never saw a photo of one until I read the George Cozens article now posted here which had them in the list of guns currently available in the USA in 1979. http://forums.deeperblue.com/threads/pneumatic-speargun-classic-review-article-from-1979.100364/
Having recently written a thread on the "Pelengas" gun which has a transverse pin holding the rear body onto the inner barrel I pulled the gun down again and instead of trying to turn the rear projection with my spanner I gave it a whack with a block of wood to loosen anything up after squirting the entire rear area liberally with WD40. To my surprise when I pushed down on the plastic rear housing with the inner barrel tube pressing hard and standing vertically on my work table the whole assembly slid rapidly down the inner barrel tube and all was revealed. Sure enough the inlet valve body is fixed with a cross-pin onto the inner barrel tube and it is double "O" ring sealed into the rear plastic housing which the rear pistol grip in turn slides over and is secured by more small pins. After that revelation the entire gun was disassembled in a couple of minutes. I found a tiny chunk of steel stuck in the inlet valve stem seal which had probably been the reason that the gun was taken out of service, where the metal fragment came from I do not know, but I think it had entered via the hand pump as it had progressed no further inside the gun.
So the only screw thread in the "Grinta" is the muzzle to inner barrel connecting thread, everything else is secured by transverse pins and if you don't know how the gun goes together then you would be hard pressed to take it apart. That included me until late yesterday!
The "Grinta" is a sort of Italian "Taimen", small air pressure tank of 30 mm OD , sleeve attachment of the rear handgrip (although the "Taimen" handle is a clamshell moulding) over a cylindrical (plastic) rear housing which forms the rear bulkhead along with the inlet valve body and is a very compact gun to look at, but it has a 13 mm ID inner barrel shooting an 8 mm spear! Too much spear and not enough gun, especially with a wet barrel.
I will take some photos of it in pieces after I clean everything up as right now it is all rather oily from my dismantling efforts and the oil that I had put in it when I last attacked it to protect the inner workings in storage. Note that even with the rear grip handle, which fits using a sleeve mounting on the end of the gun being completely removed the gun does not float despite being reduced to a long, slim cylinder. However if the alloy inner barrel was reduced in OD, it is now 17 mm, then maybe it could be made to float, but I have my doubts as the rear end still contains a lot of thick plastic and no air spaces. Its sister gun from Technisub was the "Jeans" which had a high-mounted inner barrel, it was not coaxial like that on the "Grinta", but I expect that its construction was very similar with just the end bulkheads offset upwards in their internal bores to mount the rear valve body and the nose cone higher up in the gun and thus moved off the central axis. I had seen "Jeans" in dive stores not long after they were released here, no one was really interested as the "Sten" ruled the pneumatic speargun world then and would be a much more powerful weapon than either the "Jeans" or the "Grinta", the latter model never being offered here as far as I know. I certainly never saw a photo of one until I read the George Cozens article now posted here which had them in the list of guns currently available in the USA in 1979. http://forums.deeperblue.com/threads/pneumatic-speargun-classic-review-article-from-1979.100364/
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