Any Springer Engineers / Tuners here - Piston remake ?

[Jimny4x4]

Looking to hear thoughts and experiences on remaking a PISTON .
I have heard of some talented people turning up seals and such in modern materials to replace LEATHER SEALS .
But wot of the PISTON tubes ?
Cracked , worn and esp the Seal retaining Nut / Screw thread that would need re-drilled and threaded on some that have had years of use .
Surely it would be a good idea although more money to turn up and remake a Piston completely to the same diameter as the original too ?
Or
re-use a better one from a different airgun but turned down to fit ?
I had a look inside an old springer as an example and also the inner surface tp the steel cylinder was well worn - that can be polished out I am told - I may be able to tackle this myself ( I think )
Any specialist here or anyone know of anybody ?

[TonyL]

We have many extremely capable chaps on here who could easily undertake the work you describe.

One thing that some have done for a number of years, for example, is sleeving the cylinder down, so we get smaller bore and a lighter piston. So, if the cylinder CAN'T be honed to get a reasonable surface, it could be sleeved down. Then a bespoke, one-off piston or, as you have said, a piston from another gun may be used, subject to varying degrees of modification.

All entirely possible and it's all been done before.

Our fine engineering peeps will be along.

Any gun in particular that you have in mind?

[Jimny4x4]

We have many extremely capable chaps on here who could easily undertake the work you describe.

One thing that some have done for a number of years, for example, is sleeving the cylinder down, so we get smaller bore and a lighter piston. So, if the cylinder CAN'T be honed to get a reasonable surface, it could be sleeved down. Then a bespoke, one-off piston or, as you have said, a piston from another gun may be used, subject to varying degrees of modification.

All entirely possible and it's all been done before.

Our fine engineering peeps will be along.

Any gun in particular that you have in mind?

I am looking at a couple of older airguns - got the idea from an old article in an old Airgun World .
Tuning for performance - on lower power but also a reduction in the ' clank ' each shot - never understood how thats achieved - more power / less recoil / better grouping of shots .
If you have a link to any old archive threads wold appreciate a PM to save wasting time asking silly questions .
Like - after all the polishing ( or sleeving ) then its the spring and the washers ....so far understand the tech behind allowing the Spring to twist freely on its ends by use of lubricant and seperate Washers/ spacers .
But 'Thrust Washer' and Washers used as weights or t provide pre-compression
- on the piston end / trigger sear end of the spring ...all a mystery to me

[Jimny4x4]

Tony it seems I'll be spending a damp winter in the garden shed , as so far no knowledegable experts have read my petition

[TonyL]

Some of our fine engineering peeps will be along, I'm sure.

The thing is, there are so many different sub-subjects regarding springer tuning and, sometimes, you're better off looking at individual little facets, and all this from a seemingly simple little powerplant with so few components.

A good place to start is by getting the book, "The Airgun From Trigger to Target".

Then look at the Useful Section up above, where there's an excellent thread on springer tuning.

Jim Tyler has a superb series which has been running for a few years in Airgun World, called "Technical Airgun". Many of us would love to see a book by Jim on the subject. However, modest as he undoubtedly is, Jim has often said that he would prefer to do a book when his studies are complete. The realities of getting such a book published will also, no doubt, be a factor. I'd love to see a compilation of Jim's working to date, just so we have everything easily to hand in one, neat publication, even if it's "work in progress".

If you google up "Spring Airgun Tuning" you'll also find plenty of information.

And, yes, there is LOADS of it, right here on the BBS, and various searches on individual subjects may help?

Generally in the UK, with our power restraints, our aim is to have rifles running efficiently, increasing consistency and enhancing the firing characteristics, hopefully leading to increased accuracy and less hold sensitivity.

Regarding efficiency....most tuners will seek to improve efficiency. But, even within this one subject, aims will be divided. Some may view a rifle that can make the power using as little swept bolume as possible to be the epitome of efficiency. Others' views may differ and say that the more efficient rifle is the one that can more efficiently use less spring power to get the same result.

So, we have to consider lots of factors - swept volume, bore, stroke, transfer port diameter, transfer port length, piston weight, static preload on the spring, spring force at rest, spring force when cocked etc. Then we go and change one little variable, namely the pellet, and all those dynamics can change with a heavier / lighter pellet, a tighter / looser pellet, its start pressure and whereabouts on the piston stroke the pellet is released.

Jim has shown us how to do the maths re springs to take much of the guesswork out of the equation but many, it seems, revert to the old trial and error methods, simply selecting a suitable spring that fits the piston and then having guides made to fit.

Many of us are quite happy to not play with altering the basic dimensions of the gun; rather stick with the manufacturer's blueprint and simply undertaking some hand finishing of internal surfaces and components, having guides made that fit the spring properly etc. and then some careful re-lubing with suitable product. And this act of simply "de-twanging" a springer results in a much more refined cycle. Accuracy may or may not be improved, but if the user is more confident, the psychological benefit alone may well yield better accuracy.

And then there are "tuned" guns out there whose accuracy has been ruined. Some of these may seemingly shoot nicer than a factory gun; other "tuned" guns could be denture-wreckers!

Hope this helps a little bit. As I say, the engineering types will hopefully be along to talk making different Pistons etc.

Oh, and just a quickie.....if making Pistons, or modifying, careful with latch rods! We have heard of cases where unsuitable material / incorrect hardening can render guns dangerous when the rod fails.

[TonyL]

Can't believe I haven't suggested this already, but......




If you can, get yourself along to our Boinger Bash on 1st/2nd April.

This will be our 13th event and it's a prescription that has proved to be hugely enjoyable and enlightening. Many of the very knowledgeable tuners that frequent these pages are present at these meets. And they are all willing to share their knowledge. No "trade" or dark secrets. Just as right here on the forum, where you'll see highly detailed threads backed up with images etc.

You'll have a great time spending a few hours in the company of like-minded enthusiasts and I guarantee you'll make multiple visits once you've been.

[TonyL]

I've just bumped up an excellent thread for you, sir.

"Building a HW35/LGV".

Make a cup of tea, put your feet up and enjoy.

Hope this is enlightening.

[Jimny4x4]

Can't believe I haven't suggested this already, but......




If you can, get yourself along to our Boinger Bash on 1st/2nd April.

This will be our 13th event and it's a prescription that has proved to be hugely enjoyable and enlightening. Many of the very knowledgeable tuners that frequent these pages are present at these meets. And they are all willing to share their knowledge. No "trade" or dark secrets. Just as right here on the forum, where you'll see highly detailed threads backed up with images etc.

You'll have a great time spending a few hours in the company of like-minded enthusiasts and I guarantee you'll make multiple visits once you've been.

Hi and thanks for the invite . May be possible . However much as I am keen , my search is for somebody else to do this engineering work . I don't have a working workshop , and as for 'latch rods' am totally out of my depth . Hence is there not some serious forum gun fixers here who can do springer work - so different from Pcp .

[TonyL]

Many simply don't have the time / prefer only to work on their own guns.

However, NickG, a Boinger Bash attendee, is very knowledgeable and can undertake sleeving / piston making etc. He has done many re-engineering jobs, sleeving cylinders, making skirtless and aluminium Pistons etc.

Depending on the gun/s in question, he may well be your man.