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

[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.

[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

[mallyally]

Shot a brand new one at the club earlier ( 2 actually ) The guy is a Glutton for punishment ( sorry Gareth )
Cool looking if you wanted a wall hanger But they will take an bit of work to make them Viable as a shooter
in fact if they got rid of that angled breech and silly barrel droop I would consider one
nice and light though !

The piston rod thing really wouldn't bother me I would make a longer one out of silver steel and Braze it in from the front

[Barryg]

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

Your post is of interest to me Pete,
My T05 460 has a T06 kit fitted soon after the T06 came out but I can't remember what the crimps were like but I have been looking at the old T05 piston and it looks real quality and was almost thinking of putting it back but I was thinking it only seems the later pistons that seem to be having the problems, could it have been around the time when Diana changed their factory, just wondering

Here is pics of my T05 piston, not sure you can see the quality but you can see the roundness and how central the stem is.

[FPoole]

Here's an idea. Why couldn't they put a short pin, the diameter of the annular groove in the piston rod, through the solid inside piece? Have this protrude into the groove only, and set flush with the outside of the solid piece of steel. Then slide the piston body(the tube) over this and crimp it on. This way the pin could never back out as it's captured by the tube and it won't be weakened like drilling and pinning through the rod would cause. Of course they couldn't crimp on top of the pin, but that should be easy enough. The splines would still be needed to stop the rod rotating and causing any wear as well. As far as Air Arms style rod, the Pro Elite was made exactly as the TX and, in FAC form, had a stouter spring than the Diana. The Diana made the power with a little less spring due to the centralized transfer port.