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

[jonnyone]

I've never experienced piston/rod failure on any Diana Ive owned going back to 1986. I have had probably over a dozen Dianas with this method of piston construction and experienced varying degrees of out of roundness, which is annoying enough, but nothing more serious.
I believe that there have been big variations in the hardness of Diana piston etc. steel over quite a number of years. The steel obviously reacts differently to the pressures of crimping. This is how the out of round issue effects some guns much worse than others. And probably why there has instances of rod detachment.
Obviously, there is a happy medium that Diana have found the vast majority of the time. But you can't help thinking they should revert back to their old system or use a new method.
It would probably restore confidence which is critical. Especially at this juncture.

Same as me. Cant recall how many Dianas I currently have but its in.double figures without any issues.

[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

[Barryg]

Yep.
I may offload mine now.
We may have to be quick though

So does this mean that both you and Pete would sell guns that you suspect are dangerous


There is something that was said by the owner of the piston in the pic, he said was that it was Umarex who sent him the piston and I was wondering if it was Umarex that done the bodge not Diana, we still don't know for sure how the stem is fixed in.

I don't think that we can compare this bodge with the 99 bodge because the 99 is a budget gun and these 52 pistons are in the 48/52/54/56/460/470/k98 and more just look at the price of a 56 and compare it with the 99 price

I think that a email to Diana is required to try to get some accurate info

[look no hands]

So does this mean that both you and Pete would sell guns that you suspect are dangerous


There is something that was said by the owner of the piston in the pic, he said was that it was Umarex who sent him the piston and I was wondering if it was Umarex that done the bodge not Diana, we still don't know for sure how the stem is fixed in.

I don't think that we can compare this bodge with the 99 bodge because the 99 is a budget gun and these 52 pistons are in the 48/52/54/56/460/470/k98 and more just look at the price of a 56 and compare it with the 99 price

I think that a email to Diana is required to try to get some accurate info

I've been meaning to sell my 34 for ages as I just don't use it and I could do with the money to either buy more BSA's or spend it on the ones I already have

It still doesn't instil any confidence in me when last year I had the sear snap and now this problem, fair enough mine isn't wobbly or come away yet but I have had it happen on a Chinese copy.

Just because the cost of the Diana's you've mentioned are far higher than the 99 doesn't mean they are built any better or with superior materials, Diana's have always been expensive in this country and that's down to the importers charging a fortune for them and that's why there's hardly any market for them.

Pete

[robs5230]

So does this mean that both you and Pete would sell guns that you suspect are dangerous


There is something that was said by the owner of the piston in the pic, he said was that it was Umarex who sent him the piston and I was wondering if it was Umarex that done the bodge not Diana, we still don't know for sure how the stem is fixed in.

I don't think that we can compare this bodge with the 99 bodge because the 99 is a budget gun and these 52 pistons are in the 48/52/54/56/460/470/k98 and more just look at the price of a 56 and compare it with the 99 price

I think that a email to Diana is required to try to get some accurate info

I have no reason to suspect my Diana's are dangerous . I've had the pistons out of the rifles on all 3 to true up the out of round front end. All 3 have solidly fixed rods that are fixed true.
At least I know mine are good for certain (at this point in time anyway).

Do you therefore mean in light of this, no one should sell a used Diana ? Or maybe even a new one ? How many out there have loose rods is anyone's guess.

I'm unlikely to be rushing into selling mine ( well maybe one of the K's as I have 2 the same). The comment about getting rid was tongue in cheek.
However, the likelihood of me buying another is very slim.

[prosport.177]

I guess on the up side Diana have made it easier for the shed tuners to tinker with the Diana as it looks like the rods come out easy!!!
Hum which is worse I wonder the hw77 cocking arm cracking and letting go, or the Diana rod coming out!!

[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.

[Barryg]

I've been meaning to sell my 34 for ages as I just don't use it and I could do with the money to either buy more BSA's or spend it on the ones I already have

It still doesn't instil any confidence in me when last year I had the sear snap and now this problem, fair enough mine isn't wobbly or come away yet but I have had it happen on a Chinese copy.

LOL thats even worse you are prepared to sell a gun with two suspected dangers i'm not sure how many suspected dangers Robs thinks there might be but he says he might be unloading his Diana quickly that doesn't instill confidence in me buying S/H,
I don't think anyone should sell a gun if they suspect its safety this piston thing needs to be resolved because the rest of the gun is the best

BTW im not sure how, say a TX piston would handle the stresses that the diana's have to put up with in America with some of the huge springs that are crammed into them, this is why Diana's are so robust.

[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

[look no hands]

LOL thats even worse you are prepared to sell a gun with two suspected dangers i'm not sure how many suspected dangers Robs thinks there might be but he says he might be unloading his Diana quickly that doesn't instill confidence in me buying S/H,
I don't think anyone should sell a gun if they suspect its safety this piston thing needs to be resolved because the rest of the gun is the best

BTW im not sure how, say a TX piston would handle the stresses that the diana's have to put up with in America with some of the huge springs that are crammed into them, this is why Diana's are so robust.

Well I certainly won't be keeping it any longer just because we've not heard what Diana have to say about the matter (if you even get a reply from Diana or even if they give a shit), if I worried about what might happen in the future with either the piston rod or the NEW trigger sear I fitted last year, then we should all worry about what might happen with the other rifles we sell and even things like our cars, I have enough things to worry about in my everyday life with out having to worry about what might happen to one of my air rifles because the maker decides to use a bit of a dodgy way to fix it's pistons together, do you think people who buy/sell HW77/97's worry about losing their thumb or the next persons when they sell it, if the sear should snap and send the piston and cylinder into some unfortunate persons butt plug.

These little things are just the final push for me to finally sell it on.

Pete

[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.

[robs5230]

LOL thats even worse you are prepared to sell a gun with two suspected dangers i'm not sure how many suspected dangers Robs thinks there might be but he says he might be unloading his Diana quickly that doesn't instill confidence in me buying S/H,
I don't think anyone should sell a gun if they suspect its safety this piston thing needs to be resolved because the rest of the gun is the best

BTW im not sure how, say a TX piston would handle the stresses that the diana's have to put up with in America with some of the huge springs that are crammed into them, this is why Diana's are so robust.

As I 've stated Barry I've had my pistons out and know the rods are centred and well fixed. And as I've also stated, I reckon its an issue with FAC predominantly.


All air rifles are dangerous, my Diana's no more than any other

I've shot Dianas since the 80's and only the last couple of days, heard of this issue. Never had an issue on any of mine.
As for the TX, they wont make anywhere near the power of the larger Dianas so we'll never know

[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.

[bighit]

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.

Letting the importer take the Flack then. sounds good to me NOT!

Says alot for their customer support and safety to the same customers. Your just a cash cow to them . Yes your first port of call may be the importer for parts other things but safety issues should be reported to the maker for an immediate action.

And yes i know other companies may do the same .

[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