A picture of the updated Diana piston with the new crimp.

[bozzer]

I very much doubt the piston rod is longer. That would mean reworking one of the major parts in this assembly. They clearly have no intention in doing that.

They are mass producing these things to a minimum cost or there would have gone more effort into this than smashing them all together with a load of pressure.

It looks like they have realised that some problems have arisen re loose rods and the odd rod coming out. So the answer is to give it a second smash together.

Not engineering purity ... but if it works it works. They aren't looking to flog Olympic Match accuracy here in these type of rifles. Just mass produced samples that will give most of the world decent enough power from a simple break barrel airgun to pop some tins in the garden or some bushy tails in the trees out to about 40 yards.

Unlike the 'Tune them to the Nth to squeeze another 3% accuracy out of them' brigade on here ... Diana aren't interested in that.

A 2 lb hammer knocks nails in. It doesn't have to be engineered to a tolerance of 0.001". It doesn't have to be Gold plated. You just want it to knock nails in and the head doesn't fly off and kill the bloke behind you. If this extra crushing fixes the safety issue ... it's sorted.

[jonnyone]

I very much doubt the piston rod is longer. That would mean reworking one of the major parts in this assembly. They clearly have no intention in doing that.

They are mass producing these things to a minimum cost or there would have gone more effort into this than smashing them all together with a load of pressure.

It looks like they have realised that some problems have arisen re loose rods and the odd rod coming out. So the answer is to give it a second smash together.

Not engineering purity ... but if it works it works. They aren't looking to flog Olympic Match accuracy here in these type of rifles. Just mass produced samples that will give most of the world decent enough power from a simple break barrel airgun to pop some tins in the garden or some bushy tails in the trees out to about 40 yards.

Unlike the 'Tune them to the Nth to squeeze another 3% accuracy out of them' brigade on here ... Diana aren't interested in that.

A 2 lb hammer knocks nails in. It doesn't have to be engineered to a tolerance of 0.001". It doesn't have to be Gold plated. You just want it to knock nails in and the head doesn't fly off and kill the bloke behind you. If this extra crushing fixes the safety issue ... it's sorted.

Very nicely put and makes perfect sense....

[Phil Russell]

So ... is there now a market for an 'aftermarket' piston pinning service?

Could it be done by drilling through then fixing a hardened steel pin in place? ... just in case?
Cheers, Phil

[robs5230]

So ... is there now a market for an 'aftermarket' piston pinning service?

Could it be done by drilling through then fixing a hardened steel pin in place? ... just in case?
Cheers, Phil

I don't think I'd be tempted to go that route Phil. A 10mm piston rod with a perfectly centred pin of say 3mm diameter leaves little enough rod either side.
Maybe on an unstressed, round piston but these are neither.

I reckon pinning may cause failure sooner than leaving as is.
Did you see the pic of the rod that snapped earlier in the thread ?

As commented in one of the earlier posts, I reckon the issues will be more apparent with our power hungry friends from over the pond.
A 52 doing in excess of 24ft/lbs experiences rather more shock than one ticking over at 11.

[Phil Russell]

I don't think I'd be tempted to go that route Phil. A 10mm piston rod with a perfectly centred pin of say 3mm diameter leaves little enough rod either side.
Maybe on an unstressed, round piston but these are neither.

I reckon pinning may cause failure sooner than leaving as is.
Did you see the pic of the rod that snapped earlier in the thread ?

I have no intention of doing this, mainly as I have no need / no piston etc but the thought came to me when I recalled all the comments at the start of the topic. There was much speculation on 'pinning'.
I must say I am surprised at Diana in doing this, even though it seems acceptable in the majority of cases. But it does seem a second rate engineering solution. If there was a piston failure in the USA I wonder if the various forms of litigation might come to bear and force Diana and presumably other manufacturers to prove that their method of construction was safe.
Cheers, Phil

[bighit]

you are only seeing what people have reported on line ,There may be another one or two or even a thousand that have let go but the owners just put it down to wear and tear and they don't use airgun forums .

Not all airgun owners are on airgun forums


Like most things out there ,people will only say "Oh mine did that too" if they hear it happened to some one else .

And if you think Diana will tell you how they put them together then go for it and ask but don't expect a reply if they know there could be an issue . Remember " Diana was shocked " surely if they were that shocked a recall may have been issued .

Did they reply to your query about the sears snapping? did you even write to them Barry ?

But until the other owners that have had it happen to their there will be an assumption of its only one that its happened to so its a one off so send the guy another piston.

Or they could be doing a HW99 and saying its fine pump more out the fools will still buy them.

[Barryg]

Did they reply to your query about the sears snapping? did you even write to them Barry ?

Here is a quote from the tuner who reported it in the first place on the DWC

QUOTE from the DWC
I heard back from Diana. March 11 2017, 2:10 AM

They emailed me last week and basically thanked me for contacting them and told me to contact Umarex for anything more on this topic. Wasn't the response I was hoping for.
I had another person contact me saying that he has a 48 with a broken trigger also. I don't know what to say except be careful guys. It all seems to be falling on deaf ears. John QUOTE.

[look no hands]

you are only seeing what people have reported on line ,There may be another one or two or even a thousand that have let go but the owners just put it down to wear and tear and they don't use airgun forums .

Not all airgun owners are on airgun forums


Like most things out there ,people will only say "Oh mine did that too" if they hear it happened to some one else .

And if you think Diana will tell you how they put them together then go for it and ask but don't expect a reply if they know there could be an issue . Remember " Diana was shocked " surely if they were that shocked a recall may have been issued .

Did they reply to your query about the sears snapping? did you even write to them Barry ?

But until the other owners that have had it happen to their there will be an assumption of its only one that its happened to so its a one off so send the guy another piston.

Or they could be doing a HW99 and saying its fine pump more out the fools will still buy them.

I had my trigger sear snap on mine last year, now it may have been because I fitted a Diana 45 barrel to my 34, now the breech wouldn't shut properly, so it was either because of that or because the sear was weak (like the others mentioned) and it finally decided to let go at that particular moment, like I said to Barry at the time it all blew up, there's no point mentioning it to Diana as they won't give a monkeys.

Now here's a turn up for the books, I've just taken my T06 piston and trigger out of my old 34 to put the T05 set up back in and the T06 piston has deeper crimps (compared to the T05 pistons crimps) and also another set of crimps next to them like the ones shown in the first photo of this thread, the second set of crimps are not as deep as the ones shown in the photo but it makes you wonder if Diana may have known about it a few years ago (I bought my T06 conversion kit 4 years ago), the plot thickens.

Pete