The Lesser Spotted Original/Diana 35

[T 20]

Well, after reading that little lot I don't feel so bad about missing out on one now.

It's really not that bad, Tone.

The more Pistons I weigh out of my spares pile, the more I'm convinced that the D35's piston weight is an issue.

Diana 52 piston = 300 grams.
Webley Vulcan piston = 270grams.
Pre war D35 piston = 250grams
MK2 Airsporter piston = 307grams.

So with the D35's piston weighing in at @ 240grams I reckon I could start off by adding at least 40-50grams in weight to it then use a lot less Spring than it came with.


Anyway I'll carry on thinking, I may be best to just rip my 11+ftlbs Mercury apart and replicate the internal dimension in the D35 --- it would save a lot of messing about.




All the best Mick

[Bluefan]

Yes Tony,

I always grease my balls when working on a Diana.

Been waiting for that

[T 20]

Been waiting for that

It's the law, Gav.

Even if you're working on a Diana with a T06 trigger you have to grease your balls.


I like to use the thickest stickiest grease I can get to hold my balls in, so I use this :-


image.jpg


Which I've also used sparingly on springs for a few years now as well --- it doesn't move far.




All the best Mick

[Troubledshooter]

In the mid seventies I PX'd my 1973 BSA Scorpion pistol for an Original 35, as a friend at the time lived in the country and was having problems with squidgers raiding his hen enclosure and snaffling the eggs, so control was needed.
I only used the open sights on the 35 and have to agree as to it's accuracy, accounting for quite a few squidgers in the process.

[Bluefan]

Cheers for that Mick I’ll give it a try , I’ve just got hold of some Rocol dri slide that I’m going to try on a newish Hw 35 if I don’t like the results I’ll try some of yours. I may have to stop reading this thread as I’m already most alarmed that I’m over 50 and don’t own a Diana 35

[Drew451]

The 35 is one of my favourite air rifles. Handles brilliantly and shoots sweetly. My .22 gives 9fpe with a paper thin breech seal so will go a bit higher. Its bog standard.
I have a .177 example that gives 5.5 and recoils like a mouse's cough. Feels fairly responsive at that possibly due to its short stroke, gives good accuracy even with my shabby technique.

[T 20]

Cheers for that Mick I’ll give it a try , I’ve just got hold of some Rocol dri slide that I’m going to try on a newish Hw 35 if I don’t like the results I’ll try some of yours. I may have to stop reading this thread as I’m already most alarmed that I’m over 50 and don’t own a Diana 35

Weirdly, Gav.

I can't recall anyone ever showing up at the Boinger Bash with an Original/Diana 35.

I was going to nip out and buy a 28mm Diana piston seal tomorrow morning but I'm thinking that an O ring would be a better idea on this one.



All the best Mick

[T 20]

The 35 is one of my favourite air rifles. Handles brilliantly and shoots sweetly. My .22 gives 9fpe with a paper thin breech seal so will go a bit higher. Its bog standard.
I have a .177 example that gives 5.5 and recoils like a mouse's cough. Feels fairly responsive at that possibly due to its short stroke, gives good accuracy even with my shabby technique.

Yes, that's the sort of power they seem to give, Drew, which is a bit of a disappointment when looking at other similar sized guns available back in the 1960s and 1970s.

I had a bit of a play with the breech seal on this one yesterday to make sure my recorded velocities were correct.
The breech seal I took out was a square section ring made from a soft plastic which had two steel shim washers underneath it.
I replaced the breech seal with an O ring but had to mess about a little with the shims, one was 0.5mm thick the other was 0.25mm.
The original stack of two shims plus the seal measured 2.8mm. I ended up with a 2.5mm cross section O ring with just the 0.5mm shim under it, so giving a stack of 3mm.
If seems like if you don't get this just right the barrel won't latch properly or the seal will leak so a bit of trial and error and patience is needed.



All the best Mick

[TonyL]

image.jpg


Which I've also used sparingly on springs for a few years now as well --- it doesn't move far.




All the best Mick

YAY!

Moly grease and springs; two of my favourite subjects. BOING!

[TonyL]

I was going to nip out and buy a 28mm Diana piston seal tomorrow morning but I'm thinking that an O ring would be a better idea on this one.



All the best Mick

Ah, a very useful re-purposing of a BSA (style) part then?

Is the idea also something to do with stroke gain, Mick?

[Shed tuner]

4x26mm port ? Taking that down to 3.0 should give another 1-2 FP just like that !
+10mm on the stroke and you'll be way over....

with a 28mm bore, synth seal, and a 3.0 port, a piston weight around 250-270g should work well. with leather, I'd say the 237g current weight=defo too light. syth and the original 4.0mm port, it'd probably be perfect.

[T 20]

Ah, a very useful re-purposing of a BSA (style) part then?

Is the idea also something to do with stroke gain, Mick?

There's basically three reasons behind my thinking of using an O ring, Tone.

First off the piston isn't the best I've ever seen so making a bronze piston head with O ring will keep it centred at the front end.

Secondly, the leather piston seal is 8.5mm wide and the cocking lever slot has 3mm of clearance, so if I make the bronze head 6.5mm wide this still gives a 1mm cocking slot clearance and will increase the stroke to 71mm without messing about with the back end of the piston.

Lastly, bronze weighs more than steel per cc, so with a bronze piston head I'm adding weight to the piston without robbing any Spring room.



I may be going off in completely the wrong direction by increasing the piston weight but I reckon it's worth a punt --- I'll have a better idea which way to go when I've stripped and measured my ratting Mercury this morning.





All the best Mick

[T 20]

4x26mm port ? Taking that down to 3.0 should give another 1-2 FP just like that !
+10mm on the stroke and you'll be way over....

with a 28mm bore, synth seal, and a 3.0 port, a piston weight around 250-270g should work well. with leather, I'd say the 237g current weight=defo too light. syth and the original 4.0mm port, it'd probably be perfect.

Going from experience in changing HW35s from leather to synthetic I reckon it'd be slammy with a synthetic seal and a 4mm port, Jon.

+10 on the stroke is just a note of the Max available with the cocking lever slots and geometry as standard, in real terms it would be unachievable because any stroke increase over 2mm would need the slot in the piston extending which would reduce that 10mm by a similar amount.

Using a Diana 28mm seal would take it upto about a 73.5mm stroke if needed, but it's a one hour round trip to buy one and I'm happy working at 71mm for now with an O ring.





All the best Mick

[jonnyone]

Good morning Mick,
After being initially slightly disconcerted drinking my morning coffee and reading of greasy balls I thankfully read on with interest!

I will be most interested to hear of your results with your experiments as I have a lovely 35s example giving low 10s in .22 which shoots great and seems as if its never been apart. But I've always wondered if it could be smoothed somewhat (bearing in mind how long that lube has been in there) and perhaps nudge power into low 11s.

It would be quite illuminating if you can arrive at a good performing 35 with power and accuracy something which Diana claimed it gave but sadly at least on power front it failed to deliver. My own thoughts were to go the route of perhaps a vortex or oem seal when I eventually get inside mine but I can see where you are coming from on the weight of piston and you may well be on to something good there.

Fingers crossed for you. I'll follow with interest.

Dave

[I. J.]

Oooh look https://www.airgunbbs.com/showthread...Original-35-22

An unashamed plug. Is there no depth this fool will stoop to?