GTA
All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Show us your Custom Airgun Parts (TRICKS-N-TIPS) => Topic started by: Paul68 on January 02, 2015, 11:21:16 PM
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Since I have a TF89 from Mike Melick I recently gave a tune to, figured I'd go ahead and set it up to use Vortek or Maccari seals. These things have no good aftermarket seals available, and the stock seals are to put it bluntly, junk. Some of you might remember my ham handed seal adapter evolution back when I made one for my TF Jet. That one used a Turkish Hatsan 125 seal with the simple flat step in the button. This one was a bit more difficult as I needed to use the standard tapered seal button design. All in all, a slightly less ham handed and prettier result. All I need now is a new seal.
The "stock" metal I use for these things as well as tophats are simple axle wheel studs. They come in a large variety of sizes, and the ends can be had in all sorts of configurations that make shaping them to your needs easy. I typically go at em with the drill press and my dremel or a grinding wheel in my drill to remove any ribs or splines, then clean em up with sandpaper. Then I can start on turning em into something.
In this case, I simply took a stud I had already set up as a B18/19 tophat, and figured out the taper I needed to form on the button by checking it against an old seal that has the right button hole size. I chucked it up in the press and set it to spinning, then used my dremel with a cutting wheel to start cutting the taper. I just get the basic taper started, check it against a fit in the seal, then remove more material, then check, and repeat until I get the proper fit. Once I got my button fitted, I use a flat file to make sure the angles are flat and square, then just take some sandpaper to it while spinning in the press to smooth and clean everything up.
Once I have the piece tapered as needed, I go for the always fun part of getting a bolt hole centered and drilled. In reality a smart person would center and drill their hole before forming the taper, that way if you end up with an off center hole you didn't waste 30 minutes shaping the piece. Fortunately, I lucked out and got a good center this time. I simply lock the piece to the table in a vice, sharpen up one of my punches to a nice point, then find center and punch it in as deep as possible so there will be no walking from the drill bit.
Once I get my hole drilled I need to set a countersink so the bolt will sit flush with the button. In this case I find a drill bit with a diam that matches the bolt head I am going to use, then drill it down until the bolt sits flush.
Once that's done, I chuck it back up in the press, double check how thick the button needs to be, then take a cutoff wheel in the dremel to it to remove the button from the bolt.
Then I run the freshly cut bottom of the button over a flat file to knock down any rough spots, then run it over sandpaper laid flat to smooth it.
Then voila, a simple yet effective seal adapter that allows you to switch a TF89,Norica,Beeman RS2 seal with a nice Maccari Apex or Vortek seal. In these pics everything should be in the order described. I still need to do a little grinding of the seal seat where it meets the piston face in order to bring the button down into the seal a bit as it is sitting a thousandth or two proud.
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Nice work unfortunately this is out of my skill level and tooling capabilities. I would otherwise definately try to make a seal adapter. Do you know if there are any aftermarket adapters availible?
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http://vortekproducts.com/ourstore/Seals-Tuning-Parts/Diana-Piston-Seal (http://vortekproducts.com/ourstore/Seals-Tuning-Parts/Diana-Piston-Seal)
Kinda funny really. It wasn't until a few months after I made the first seal adapter for my TF Jet a year or two ago and sent one off to someone so they could try their hand at copying one on better machinery that Vortek came out with what looks like the same thing. I don't know what seals their adapter will work with though.
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Lovely think I'll give it a go. My 87 is not to consistent in velocities and is spraying pellets I think the seal may be nicked. I'll have to tear down and see what's going on with it but I'm quite busy right now
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So what size is the piston seal on these guns?I just want to make sure this thing actually fits the compression tube. Says the kit will fit some other 28mm guns. Are these 28mm I haven't had mine apart to find out yet figured you would know...
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Not sure of the 87's, but I believe they are 26 mm seals, and they are definitely 26mm seals in the 89's. You'd have to get the adapter, then a 26mm seal. Usually I see the ARH oversized small APEX seal used in these guns.
http://www.gatewaytoairguns.org/GTA/index.php?topic=80238.0 (http://www.gatewaytoairguns.org/GTA/index.php?topic=80238.0)
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Lovely think I'll give it a go. My 87 is not to consistent in velocities and is spraying pellets I think the seal may be nicked. I'll have to tear down and see what's going on with it but I'm quite busy right now
Ever get the Vortek adapter installed?
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No paul not yet been busy at work I hope to get it done within the next week or so. When I do I'll post the results here.