HW35, a few questions

[T 20]

Hopefully the next 35 I build up will be a .22" E with carbine Barrel as my new ratting gun, but I may build my own rotating 30mm piston for it.
I've been toying with this idea for a while, by using a bobin shaped piston body with bearings either end and a TX latchrod with 72mm stroke it should give a nice lazy firing cycle.

Like this :-

image.jpg

[TonyL]

Like this :-

image.jpg

That's well perty, Maestro.

Another benefit, which I'm sure you will have considered already, of such a design will be the ability to use a smaller diameter spring.

[T 20]

Another benefit, which I'm sure you will have considered already, of such a design will be the ability to use a smaller diameter spring.

That's not really a benefit, Tone, it just comes as a consequence of the piston dimensions, the new piston has a 21mm ID so cutting down my choice of springs.


Hopefully there are a few benefits to the new piston though. :-

The tail of the original 35 piston is soft and tends to score on the cylinder, the tail of the new one has a bearing so no scoring and minimal lubrication required.

There is no need to mess about with piston liners on the new piston as it has no cocking lever slot.

With the new piston being able to rotate on firing this should take a bit of pressure off the top hat and guide to provide rotation.

The new piston is coming in at about 10 grams lighter than the old one and there is still room to reduce that even more if needs be --- don't forget this piston is just a quick lash up to see if it's worth doing properly, hence the use of LGV bearings as I had them to hand.

With the new piston having a screw in latchrod the stroke can be easily altered by changing the latchrod length.





All the best Mick

[TonyL]

Going to be interesting, Mick.

Sure you'll be okay for springs too; plenty out there with 21mm and less OD.

[T 20]

Checking back through my photo albums it seems I'm following in Wonky Donky's footsteps here as he made a similar rotating piston for a HW80 :-

image.jpg


http://www.airgunbbs.com/showthread....59#post6308359

[TonyL]

Oops!

It appears that I inadvertently boinged that thread back up. Very nice read.

Hope Dave is keeping well.

[pigeondave]

Oops!

It appears that I inadvertently boinged that thread back up. Very nice read.

Hope Dave is keeping well.

Me Dave?

Yes I'm good Thanks.

I've fitted my Tinbum kit and the rifle is now making 10.6ft/lb with H&N FTT @14.76grain
the fps were, for 12 shots
592.2
582.8
575.6
572.6
568.7
569.6
566.7
566.7
564.8
563.8
566.7
566.7

there is a bout 2" of preload on the spring. It was quite a job to get it all together again.
After we (me and the old man) got it back together, the old man thought that the butt pad for fishing would have probably made the assembly easier.

Quick question

Would 2 people using the same rifle have a different zero?

We are both grouping tight over 20m but my shots seem to be high and to the right (think 1 0'clock) compared to the old man.

Good news is that things are hotting up in the garden plinking cup he won this weekend, I won the first week we shot.

I'm now looking for a HW98 or a HW97KT to joint the HW35.
With a view to getting it professionally tuned to see what the difference is.
And maybe a HW100 but that looks like I'll need a lot of additional kit, bottles etc

[Bluefan]

Like this :-

image.jpg

That's just too nice
I'm actually suffering now.

[CapitalBee]

Like this :-

image.jpg

Mick,

Will the latch rod have to have a ball end (like the LGV) to allow rotation and if so, will you have to cut a rad' in the top sear?

[T 20]

Mick,

Will the latch rod have to have a ball end (like the LGV) to allow rotation and if so, will you have to cut a rad' in the top sear?

Yes Mark,

I'll be using a MK3TX latchrod and the top sear will be altered like this :-

image.jpeg

image.jpeg

[Duggan]

I must say I like the HW35 very much, I have four, two are standard Exports with 22 inch barrel. But I also have a Vixen in a delux stock in .177 and a Venom version in .22. I enjoy using them and looking at their classic lines. There are some real beauties on this thread.