The Lesser Spotted Original/Diana 35

[T 20]

now just leave the poor old girl alone and just shoot her

Nah, where's the fun in that, Jon ?

Next up is piston weight back down in the 270s with factory 33 coil Spring --- I've got some cable ties left so I may as well use them.

This will give an indication of what power can be achieved with a Protek synthetic seal conversion kit and a factory Spring for the folks without a lathe.




All the best Mick

[TonyL]

Any normal fettler would be declaring this as "job done" and be happy to just shoot and enjoy now.

But I think Mick has really got into playing with his tie wraps, lubed up shaft and greasy balls!

Your further experimentation will help others for sure, Mick. Well done for utter dedication.

[T 20]

Next up is piston weight back down in the 270s with factory 33 coil Spring.

This will give an indication of what power can be achieved with a Protek synthetic seal conversion kit and a factory Spring for the folks without a lathe.

With the "Original/Diana" factory 33 coil Spring with 276 gram piston, chrono results were :-

Hobbies = 580fps

Superdomes = 500fps


So I stripped the gun again and weighted the piston back up to 305 grams and put the 28 coil Spring back in but added 4mm of extra preload to see if it would lift the power a tad, results :-

Hobbies = 610fps

Superdomes = 590fps



So the tune I've now chosen to go with is the 270gram piston with 28 coil HW95 Spring with 16mm total preload that gave 11.6ftlbs with Hobbies.

11.6ftlbs will do me for a bit of paper punching in the garden and dealing with the occasional rat.



All the best Mick

[TonyL]

How does it feel to shoot in this current tune, Mick?

If you're happy with the cycle and the resulting accuracy, is this "job done" now?

[T 20]

How does it feel to shoot in this current tune, Mick?

If you're happy with the cycle and the resulting accuracy, is this "job done" now?

I'm not happy with the firing cycle with the 305 gram piston, Tone.

The best firing cycle was with the 276 gram piston with Hobbies giving 11.6ftlbs which is why I'm going to strip the gun back down and reset to that tune.
With the 276 gram piston the firing cycle was not quite right with Superdomes for some reason, but firing Hobbies was really nice, it's hard to describe but with Hobbies everything seemed to work in a no nonsense fashion --- I pulled the trigger, the piston shot forward and the pellet came out with very little movement of the gun.




All the best Mick

[Shed tuner]

big difference in weight between the hobbies and the domes.. pick and one tune for it
300g is going to get a bit heavy in terms of recoil, so I think your 276g is bang on. Just play with springs / add preload to taste

[TonyL]

Guessing we're now getting into "slammy" territory, Mick, but that's an area where your good self, JB and a few others have more understanding than many of us.

Re the Hobby vs Superdome observations, guessing that will be down to the different pellet release pressures. The Hobby is noted by Jim as being high in this regard, but the 'Dome higher still. Just goes to highlight how interlinked all the differing factors can be.....piston weight and momentum, pellet release pressure, TP size, spring force & rate, preload etc etc.......You'll find that "sweet spot" / balance.

[T 20]

Guessing we're now getting into "slammy" territory, Mick, but that's an area where your good self, JB and a few others have more understanding than many of us.

Re the Hobby vs Superdome observations, guessing that will be down to the different pellet release pressures. The Hobby is noted by Jim as being high in this regard, but the 'Dome higher still. Just goes to highlight how interlinked all the differing factors can be.....piston weight and momentum, pellet release pressure, TP size, spring force & rate, preload etc etc.......You'll find that "sweet spot" / balance.

To be honest, Tone.
I wasn't really comfortable with a 300 gram piston flying around in such a lightweight gun as it goes against everything we know on recoil and surge.

276grams I can live with, and with having to fit a bronze piston head and steel piston liner to correct the piston there isn't really any way of shaving much off that figure unless I machine a new head from Aluminum, which I won't be doing now.

Anyway, this morning I totally stripped the action and took the time to drill and polish the transfer port properly at 3mm.
Then I cleaned out the cylinder and transfer port and cleaned the piston, that's when I noticed a little problem, the piston head had a mark all around it's edge where it had hit something at the end of the cylinder --- so I had a look in the cylinder. :-

image.jpg


There was about a 1mm wide ridge sticking up on the outside of the plug that coincided with the witness marks on the piston.
After thinking about making a tool to slide in the cylinder to take the ridge off, I said bugger it and machined the 1mm ridge from the front face of the piston --- job done.
Relubed and reassembled at my original 276 gram build with just 1mm of extra preload using all new seals again I fired a few Superdomes over the chrono. :-

image.jpg

image.jpg




Hobbies are still doing 11.6 so that'll do for me.



As is normally the case on my last buildup of the trigger unit I discovered something that makes reassembly easier.
I've been struggling to get the trigger blade pin back in every time I've built this gun up and even altered a pair of pump pliers to assist in crushing the trigger spring, well this morning I realised what the unused hole was for between the stock bolt hole and the cocking lever slot.

If you stand the action upright on its backend you can push down on the sliding sear with a screwdriver to get the trigger sear hole in the middle of the window in the action. :-

image.jpg



While holding the sliding sear down you can then insert a 3mm (or larger) drill bit into the forward hole to hold the sear in the cocked position.

image.jpg


Then you can fit the trigger without struggling.




So that's it, I'm done and dusted with this one even though I could go further I'm calling it a day on my Original 35 --- what fun it's been.





All the best Mick

[TonyL]

To be honest, Tone.
I wasn't really comfortable with a 300 gram piston flying around in such a lightweight gun as it goes against everything we know on recoil and surge.

276grams I can live with, and with having to fit a bronze piston head and steel piston liner to correct the piston there isn't really any way of shaving much off that figure unless I machine a new head from Aluminum, which I won't be doing now.

Anyway, this morning I totally stripped the action and took the time to drill and polish the transfer port properly at 3mm.
Then I cleaned out the cylinder and transfer port and cleaned the piston, that's when I noticed a little problem, the piston head had a mark all around it's edge where it had hit something at the end of the cylinder --- so I had a look in the cylinder. :-

image.jpg


There was about a 1mm wide ridge sticking up on the outside of the plug that coincided with the witness marks on the piston.
After thinking about making a tool to slide in the cylinder to take the ridge off, I said bugger it and machined the 1mm ridge from the front face of the piston --- job done.
Relubed and reassembled at my original 276 gram build with just 1mm of extra preload using all new seals again I fired a few Superdomes over the chrono. :-

image.jpg

image.jpg




Hobbies are still doing 11.6 so that'll do for me.



As is normally the case on my last buildup of the trigger unit I discovered something that makes reassembly easier.
I've been struggling to get the trigger blade pin back in every time I've built this gun up and even altered a pair of pump pliers to assist in crushing the trigger spring, well this morning I realised what the unused hole was for between the stock bolt hole and the cocking lever slot.

If you stand the action upright on its backend you can push down on the sliding sear with a screwdriver to get the trigger sear hole in the middle of the window in the action. :-

image.jpg



While holding the sliding sear down you can then insert a 3mm (or larger) drill bit into the forward hole to hold the sear in the cocked position.

image.jpg


Then you can fit the trigger without struggling.




So that's it, I'm done and dusted with this one even though I could go further I'm calling it a day on my Original 35 --- what fun it's been.





All the best Mick

Brilliant information again, Mick.

But are you REALLY done with it?

[BTDT]

The Hobby is noted by Jim as being high in this regard, but the 'Dome higher still.

Actually, Tony, the Hobby has a higher start pressure than the Superdome.

[T 20]

Actually, Tony, the Hobby has a higher start pressure than the Superdome.

That probably explains why it felt better firing Hobbies than Superdomes then, Jim.






All the best Mick

[TonyL]

Actually, Tony, the Hobby has a higher start pressure than the Superdome.

I stand corrected. Thank you, Jim.