The Lesser Spotted Original/Diana 35

[TonyL]

You could well be right, Jon, but that would be of interest to those with .177" Original 35s.

Everything is prepared now ready for the big build and looking very sexy if I say so myself.
The piston ended up at 276 grams once I'd added a Delrin top hat.
The barrel was only slightly bent upwards but it's dead straight now.
As I had 16mm of preload with the leather sealed piston I've kept that the same for the build up with an O ring seal, having 6mm of top hat/slip washer in the piston and a 10mm stack of Dowty washers on the spring guide.
If it does go over I can simply remove preload from the back end and not disturb the piston which will give me a better idea of what it's doing.
If I feel it needs more piston weight I can simply pull the top hat out and I have some 10mm washers that weigh 4 grams each I can load the piston with, but I can only physically get four in.

If I get some numbers tomorrow I'll post them, but then I'll have to make a spring compressor before carrying on with the fine tuning.




All the best Mick

Eyes peeled.

[T 20]

Without further ado :-

Superdomes =10.28ftlbs

Hobbies = 11.08 ftlbs


So without any detonation I've lost 0.9ftlbs.

But, and it's a big but, the gun now cocks as smooth as silk and is near enough recoilless --- yes I know everyone says that but this is a really fast firing cycle with very little movement.

There's several ways I could go with this but I'm tempted to leave it alone and maybe just put some diopters on it for garden plinking.

Other thoughts are buy a new Spring as I don't know this one's history.
Weight the piston some more to see if Superdomes velocity rises.
Remove the 10mm of preload washers and see what it does --- it could be over sprung.
Drill out the transfer port but I feel it's good enough at 2.8mm.


I'll have another think on it, but I'm happy at 11 with Hobbies --- and before anyone says try FTTs, the barrel is that tight that I near enough have to hammer them in.




All the best Mick

[TonyL]

Laugh? Us lot have a laugh? I very much doubt that that would or could ever happen, Mick, and we bow to your undoubted talent and knowledge.

As you have touched on already, with the rifle already cocking and shooting so sweetly, I'd be tempted to say, "job done", and be happy with it.

But then you're more adventurous and better equipped than the vast majority of tinkerers.....

[evert]

I'll have another think on it, but I'm happy at 11 with Hobbies --- and before anyone says try FTTs, the barrel is that tight that I near enough have to hammer them in.



All the best Mick

Try JSB RS, they can often be even more effective than the Hobby.
Anyway, 11fpe with low recoil should be good enough for anyone!

[crowbar]

If the barrel is tight I would try Crossman pellets and as you found the T.P. is shorter than a B2 I would be looking at
opening it up to 3mm and see.

[T 20]

T.P. is shorter than a B2 I would be looking at
opening it up to 3mm and see.

Yes, after a quick calculation I can open the transfer port to 3mm and still be OK.
The tricky bit will be opening the transfer port without stripping the gun, but I reckon if I hold the action vertically with the transfer port facing down and turn the drill by hand I should be OK --- I may even grease the bit to catch the swarf as I break through.

Obviously the fine tuning is where the Original 35 falls flat on its arse compared to a HW35 or Mercury as removing and replacing the three ball trigger is so time consuming.
On a Weighrauch with a screw in back block I could easily try out 6 different Spring setups in an hour, on the Original 35 it would probably take all day to do that.
Tonight I actually found a couple of alternative springs to try out in the gun, the first one is a good straight genuine Original 33 coil factory Spring of 3.3mm wire, the other is a 35 coil Spring with 2.8 mm wire --- but I'll try the transfer port first.




All the best Mick

[T 20]

T.P. is shorter than a B2 I would be looking at
opening it up to 3mm and see.

Well after you pointed this out, Crowbar, I did a few more calculations on the transfer port.

I'd taken someone else's measurement of the transfer port at being 26mm long as correct --- it wasn't, this could be down to the fact that there's basically three different "Original 35" models.
I previously measured my transfer port at 19.2mm, having measured the 3mm drill bit this morning (sad or what ?) I found the centreline of the port is exactly 20mm long.

Working from the known static compression ratio of my HW35E which feels bob on. :-

48/0.1606 = 298:1

From my previous calculations of the Original with a 26mm long port I had a static compression ratio as :-

43.12/0.1606 = 268:1

My static compression ratio yesterday with the 2.8mm port was actually. :-

43.12/0.1232 = 350:1

After drilling out the Original port to 3mm this morning I have this SCR :-

43.12/0.1414 = 305:1


And the results of drilling out the transfer port to 3mm :-

Hobbies average 660fps for 11.61ftlbs

Superdomes average 570fps for 10.46ftlbs


The firing cycle seems to be unaltered --- maybe a bit softer but it's easy to convince yourself that's the case after a modification.

So that's it for now, at 11.6 I'm not playing with it anymore even though I would like to add weight to the piston to see if Superdomes gain any speed, but the ball ache of dismantling the trigger says forget it.


One top tip I have found for Original 35 and 50 owner is that if you put a small cable tie round the end of your shaft it's easier to slide your balls in.
Once you have the front pin in and your top Spring is secure you can simply cut through the cable tie with a Stanley knife through the trigger hole and remove it.






All the best Mick

[TonyL]

if you put a small cable tie round the end of your shaft it's easier to slide your balls in.


All the best Mick

[crowbar]

Are you saying three different lengths were used over the years ?
I don't have a 35 but I have three 27's ,a early 50's Milbro, a 1966 Original and a 1976 Original and they all have a 16mm
(5/8") long transfer port .

On my "Supa Dupa" one (530f/s) I made a brass trigger block with pin holes and a spring slot to beef it up.

IF ONLY THEY HAD BEEN DESIGNED RIGHT AND HAD A 6MM LONG TRANSFER PORT !!

I now have a Original 35 which I have stripped and checked the transfer port and it is 3mm dia and just shy of 20mm long on a rough measure with a steel rule so I think your one has been altered by a earlier owner also it has no collection pocket drilled into the face .

[T 20]

Are you saying three different lengths were used over the years ?
I don't have a 35 but I have three 27's ,a early 50's Milbro, a 1966 Original and a 1976 Original and they all have a 16mm
(5/8") long transfer port .

On my "Supa Dupa" one (530f/s) I made a brass trigger block with pin holes and a spring slot to beef it up.

IF ONLY THEY HAD BEEN DESIGNED RIGHT AND HAD A 6MM LONG TRANSFER PORT !!

No, I was speculating that as M & G had made three different versions of the LG35, 1953-1964, 1964-1987 and the 35s, so the forum member's measurement of 26mm of the transfer port could have been correct, but for a different version to mine.
My LG35 definitely has a transfer port of 20mm, 17mm of it was bored at 4mm, the last 3mm is a little collection chamber in the centre of the cylinder end face.

The little collection chamber was the reason I went so conservative with the 2.8mm ID transfer port as I didn't know what volume the chamber was.

I'd be happy to play with another Original/Diana gun as long as it had a T01 or T06 trigger fitted.





All the best Mick

[T 20]

The LG35 trigger unit is on a different level to most guns, Tone.

To reassemble, the three ball bearings need greasing to hold them in the central carrier, at the rear top of the central carrier is a slot that you have to put a spring with its little spring guide in, then you have to poke this lot into the cylindrical sear that's in the gun.
If you put a small cable tie round the front on the spring guide shaft to hold the spring then life becomes much easier.

The spring guide acts as the forward stop for the cylindrical sear and the tail of the piston pushes on the cylindrical sear to set the trigger.
Once you get your head round it everything makes sense but understanding it doesn't make the reassembly any quicker.

I've only ever come across a similar arrangement in industry once before and that was on a hydraulic muck scraper in a dairy cattle shed.




All the best Mick

[Shed tuner]

Have you got any softer pellets Mick ? e.g. the Falcon AP, or JSB RS or Express ? Domes and hobbies are both hard, high start pressure pellets. The higher ME with hobbies makes me think that a lower start pressure pellet might be more efficient...

Either way though, 11 + with hobbies is a great result

[HW777]

I'd be happy to play with another Original/Diana gun as long as it had a T01 or T06 trigger fitted.

There'll never be a T07 Mick but that doesn't mean T05 shouldn't get a look in

If I could find a Model 46 compact .177 T05 trigger, there is atm the opportunity to upgrade to T06

Atb

John

[T 20]

Have you got any softer pellets Mick ? e.g. the Falcon AP, or JSB RS or Express ? Domes and hobbies are both hard, high start pressure pellets. The higher ME with hobbies makes me think that a lower start pressure pellet might be more efficient...

Either way though, 11 + with hobbies is a great result

Unfortunately I only have Superdomes, Hobbies, FTTs, Superfields, Wasps, Barracudas and Napier power hunters at the moment in .22", Jon.

Most of my .22" guns either take Superdomes or FTTs.


I'm happy with the 11.6ftlbs with a 28 coil 3mm wire Spring when the factory Spring was 33 coils of 3.1mm wire.

Still niggling at the back of my mind though is the fact that I can still stuff another 20 grams of weight onto the piston and still use the 28 coil Spring, which could make a difference with Superdomes.




All the best Mick

[T 20]

There'll never be a T07 Mick but that doesn't mean T05 shouldn't get a look in

If I could find a Model 46 compact .177 T05 trigger, there is atm the opportunity to upgrade to T06

Atb

John

Good luck in your quest, John.

I'm actually quite happy with the T01 triggers in my 52 and 54 and never even considered swapping them for the T06 when those kits were available at a reasonable price, I even have a spare T01 trigger and piston --- just in case, like.



All the best Mick