Thanks, Ron!Your sizing method sounds about what I've heard many others use. But details such as what grit papers to use are invaluable.The file I used yesterday left a very lightly grooved, unpolished surface to the seal sides. I feel this will help lube retention and not hurt the sealing. My LGV's piston seal has slightly dimpled sides for the same reason. Vortek parts are basically unavailable here (they seem happy to supply the North American market), so that's a no-go.
Thank you for the support, Hector! Re: seal size markings; I'm only going by the Whitefang quote, and the fact that I have a couple of guns where just the 0.1 mm above compression chamber ID created the perfect fit. Even if we ignore the markings, the fact remains that the OEM seals are far from a drop-in size. A quarter-mill around is like the thickness of a sturdy playing card needing to come off.I have a fair bit of experience turning wood, and some turning plastic, Delrin. With Delrin, a razor sharp tool is not recommended if even possible, scrapers work best. High RPM with Delrin can result in melting. Now, the plastics used in piston seals are a completely different material, with different turning properties. There, a shave with a sharp bit at high RPM may be just the ticket.TBH, shaving a seal into an exact fit sounds downright scary, as unlike when turning wood items, just a hair too much results in a scrap seal.It'd be a hoot to hear how other tuners size their seals, if that's not too much of a trade secret.
I have never trusted delrin, LOL!It's too finicky a material to do anything really useful.
I'll sure be trying 220-240 grit sandpaper on rotating piston seals in the future, and see for myself how fast it takes off material.
Quote from: HectorMedina on January 30, 2022, 02:38:12 PMI have never trusted delrin, LOL!It's too finicky a material to do anything really useful.Hector, your distrust of Delrin is well-documented, LOL! But literally thousands upon thousands of Delrin guides have been made and used, for millions upon millions of shots - it is the prevalent springer guide material, and not only within the mass production realm. Delrin is the guide material of choice of most custom parts makers. So your statement of its usefulness is at odds with reality.Late last year I spent quite a bit of time at the British airgun forums. Really interesting stuff. One man's experience, like mine, is one thing, but when professional aftermarket guide makers, who have sold tens of thousands of guides each, SWEAR by Delrin, and report that extremely few Delrin guides ever fail, and if they do, they fail within the first dozen shots or so, due to a fault such as a poorly finished scragged spring end, and that Delrin is the ONLY guide material they use, because Delrin has the best mix of properties for guide making and use, you kinda have to listen. All that being said, guides can be made from many different materials. Each have their own strengths, weaknesses and user biases.