I'm Sat Waiting On Postman Pat

[T 20]

The stroke is somewhat limited by the cylinder in itself. I think you may be able to reach 75mm, but not much more.
And you may probably reach those 75mm's by just trimming the front of the piston.
I'm a bit afraid to take too much off and have the piston coming apart during cocking.

As I started out with a 65mm stroke piston my machining for the TX piston seal is now within 0.5mm of the cross pin hole, so machining the piston face back any further is a none starter strength wise, Evert.

I'm pretty confident that altering a 99 piston could be my best bet --- but if someone could tell me the overall length of a HW99 piston I'd know for sure ?




All the best Mick

[evert]

As I started out with a 65mm stroke piston my machining for the TX piston seal is now within 0.5mm of the cross pin hole, so machining the piston face back any further is a none starter strength wise, Evert.

I'm pretty confident that altering a 99 piston could be my best bet --- but if someone could tell me the overall length of a HW99 piston I'd know for sure ?




All the best Mick

I havent seen any cross pin hole
Looks to me like it was brazed toghether.

[BTDT]

I havent seen any cross pin hole
Looks to me like it was brazed toghether.

My HW55's piston has a cross pin.

[T 20]

I havent seen any cross pin hole
Looks to me like it was brazed toghether.

My 50 piston has both cross pin and brazing :-

image.jpg

[HW777]

Threaded interchangeable piston heads and shallow piston seals would assist with piston stroke length in Mk1 Hw50's

Rather time consuming though but something to consider if you have the time and skill to do it

[T 20]

Threaded interchangeable piston heads and shallow piston seals would assist with piston stroke length in Mk1 Hw50's

Rather time consuming though but something to consider if you have the time and skill to do it

Hi John

If my calculation of the HW99 piston length being 146mm overall, then by machining the Weihrauch piston seal arbor off to expose the piston rod, I could thread the rod to use interchangeable piston heads.
By doing this I could easily alter the stroke between 71mm up to 76mm.

The other alternative I've been looking at is using a TX200 latch rod in a homemade piston body, I could then simply increse the stroke by screwing the rod further into the body --- I'd need to alter the Rekord top sear to use the TX rod but that's a simple enough operation.

Something else I need to have a Squint at is the possibility of using the piston I've already altered but extending the stroke by moving the Rekord pin holes backwards in the back block.
This would increase the stroke and also give a setback trigger, but I have a feeling there's not enough room in the block to do it.




All the best Mick

[TonyL]

Something else I need to have a squint at is the possibility of using the piston I've already altered but extending the stroke by moving the Rekord pin holes backwards in the back block.
This would increase the stroke and also give a setback trigger, but I have a feeling there's not enough room in the block to do it.

All the best Mick

Wow! Now that is extreme thinking out of the box. Guessing, like you say, that there may not be enough room to allow this, but you never know.........

[T 20]

Something else I need to have a Squint at is the possibility of using the piston I've already altered but extending the stroke by moving the Rekord pin holes backwards in the back block.
This would increase the stroke and also give a setback trigger, but I have a feeling there's not enough room in the block to do it.

Wow! Now that is extreme thinking out of the box. Guessing, like you say, that there may not be enough room to allow this, but you never know.........

Yes, Tone --- after measuring it up there wouldn't be enough gain to make it worthwhile.

A little trick I do when long stroking HW35s to check if the cocking linkage will still work at a longer stroke is to remove the mainspring and wind out the back block by the amount I'm adding to the stroke, and check that it still cocks.
That's to say if I'm stroking a synthetic sealed HW35 from it's standard stroke of 69mm to 71mm I unscrew the back block by 2mm and check that the gun still cocks.

Having just remembered this trick I'll have a little play with a HW50 this afternoon and see what it can be stroked to.




All the best Mick