Indeed, Paul.
I also have a few rifles fitted with synthetic V-Mach items - still all going strong.
As indeed are the ones that I have fitted with the TbT and Welsh Willy items (as Pete says above) which have also been fine.
Seeing Nick's information on failure rate sheds good light on this.
And I suspect that a good proportion of those that did fail may have been down to other factors - insufficient preload being one of them, where the spring could pull the end of the guide away from the end block and then slam it back into the block.
Last edited by TonyL; 25-11-2023 at 07:00 AM.
THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
NEXT EVENT :- May 17/18, 2025.........BOING!!
Yep, and guessing that's why some of the knowledgeable tuners went / go for a fixed guide, Pete. By the way, I can't take any credit for that theory and have seen it quoted on here a few times in the past.![]()
THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
NEXT EVENT :- May 17/18, 2025.........BOING!!
Yep, just a little "knob" to center the spring on the rear block on the Hawk, and a small recess with a rubber disc on the Osprey.
An they carried on with the Tracker, using a cut down piece of the spring tamer plastic guide from the Vulcan, and just let it free-float inside the spring
Which reminds me that my Hawk deserves a new spring guide and a transfer port sleeve...
Too many airguns!
After Gerald Cardew fettled my Mk1 HW80 1982/3, John Knibbs came out with his Titan Accelerator spring made in Sweden close coiled for one & a half inches at one end with a blue ceramic coating I bought one from John it was too long spoke to john on the phone he sent me another cut & finished, I bought a John Bowkett long spring guide & power washers; about 30 years later during a quinquennial service I noticed the Bowkett guide was necking down a little about an inch up, the HW80 now sports a 2 piece TbT guide & top hat & washers & Bum Slide.
Last edited by palace; 25-11-2023 at 11:48 AM. Reason: accuracy
AA S410K:Cardew modified Mk1 HW80 4mmTP, barrel shortened no choke Venom Tyrolean stock Titan Accelerator spring, TbT top hat & guide :CZ 16"bbl .22LR Varmint:12bore MOB O/U: Webley 812 auto:.308 Surgeon/Border barrel by Dave Wylde now Valkyrie Rifles BASC/NRA
I have always made single piece guides from delrin and have not had any failures to date. I have come across a failure though ... separated at the end. Also a guide where an unfinished spring end had ground its way through the guide body just in front of the flange.
But I keep telling myself I must make a 2 piece guide next time I need one ...Why? less wastage on material and because of comments on here. Question....if I made a 'bevelled' end flange and guide rod (tube), is there a recommended angle for the end flange. 45 degrees? 30 degrees?
I may well have one or two ex HW metal end flanges so guess I could copy that design.
Cheers, Phil![]()
I have two Tinbum kits and I am satisfied with both but my favourite is the one piece steel guide that Steve Pope made for me for my TX
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I've just opened up a Mk2 Meteor made as above with a slight radius where the washer will fit. The washer has been machined to a taper fit just as in the previous posts and as T20 says as Weihrauch do it, all be it with a metal washer/delrin guide.
The washer taper has the factory dark grey coating so it's not been done after manufacture.
The more I think I know, the more I realise the less I know.
Regarding breakages of plastic guides, it's worth knowing that not everything sold as Delrin is actually Delrin. There are two closely related plastics, the homopolymer version (POM-H) is Delrin, a Du Pont trade name, the other is a copolymer (POM-C).
They have different mechanical properties but are often sold interchangeably.
POM-H is stronger in thin sections, more expensive, and suffers from porosity in the middle of large sections, as you might find in the middle of 25mm rod for example. POM-C has no porosity, can be more dimensionally stable, and is more chemical resistant.
Just to confuse matters more, Delrin is sold in different molecular weight versions named 100P to 900P.
Delrin is reckoned to be about 15% stronger and stiffer, and can take about 10% more load before creeping.