Weihrauch HW55

[nick_mantis]

Misplaced my punch set but finally got everything apart this week.

Hmmm, maybe not quite standard. Anyone recognise it?

[evert]

Misplaced my punch set but finally got everything apart this week.

Hmmm, maybe not quite standard. Anyone recognise it?

Not standard at all, but very interesting, and perhaps example of tuning work?

I've been thinking about assembling pistons like this, with front plugs threaded into the piston body.
But this seems like a good example of how threads will be stress risers in the design of a piston.
At the same time, milling the cocking slot that far into the threaded portion of the piston is asking for trouble.

Has the gun had any cylinder damage from the piston failure?

[nick_mantis]

Need to have another look to make sure but didnt notice any scratch's when looking down the bore.

Looking at it and comparing it to any pictures you can find of the stock piston the front looks very similar. So it could be a stock piston that has been cut down and and threaded, which would account for the slot being so far into the thread as it was already in there to start with.

The threads don't look to have been damaged either so it might be possible to replace the body..... if anything fits on it.

It is in the full match stock so tuning during its life is well within the realms of possibility.

[T 20]

Misplaced my punch set but finally got everything apart this week.

Hmmm, maybe not quite standard. Anyone recognise it?

I'm not the world expert on these things but that piston doesn't look like a Weihrauch product to me, every Weihrauch piston I've ever seen has been brazed and pinned together.

It could be a custom piston or it could be a piston from a different manufacturer.

HW50 piston :-

image.jpg





All the best Mick

[deejayuu]

Here's a couple of 55 pistons
One earlier than the other https://photos.app.goo.gl/zwV6odNxi1gN1xQQ8

[crowbar]

Comparing the pic's it looks like the lower one of the two, so I think it is original piston with a O ring piston mod and a extra slot? to lighten the piston but I can't see for the latch rod.

[deejayuu]

Comparing the pic's it looks like the lower one of the two, so I think it is original piston with a O ring piston mod and a extra slot? to lighten the piston but I can't see for the latch rod.

The 50 has steel head and one slot. The 55 has the alloy head and two slots to reduce weight. Not convinced the stock 55 is threaded head tho'. Thought it was interference with cross pin. May have to investigate.

[crowbar]

Do your two pistons have aluminium heads?

Do they have two slots?

Are the heads pinned with a dowel?

Threads were used to fix breech blocks to comp tubes on early guns and soft soldered so I still think the long head will be
threaded and the short head brazed.

[edbear2]

P.M. sent about possible fix, have posted this to bring thread up to the top for the O.P. (you also have P.M.) as is time critical, so hope he spots it!

ATB, Ed

[T 20]

Here's a couple of 55 pistons
One earlier than the other https://photos.app.goo.gl/zwV6odNxi1gN1xQQ8

That's certainly buggered my theory then Jules.

Looking at the damaged piston I'm surprised it lasted as long as it did.

I must get round to stripping my 55 some time to see which piston it has as I'd be better off with the synthetic one so that I can long stroke it using a TX seal.


All the best Mick

[evert]

Seems like there is a lot of different pistons in the old 50 and 55, both between the models and within the models.
We should really make a thread on it, and gather pictures and all the facts we can find.

Other than that, a threaded aluminium head sounds like a recipe for disaster to me.

[nick_mantis]

The piston that has come out of mine has:

Aluminium head
Double slotted steel body
Adapter for synthetic seal but that is literally just attached to the front of the head with a single screw as the leather ones are.

The body was screwed onto the aluminium head with a pin running right through presumably to stop it unscrewing itself. The pin is offset to allow for the steel catch bar running down the middle.

On my internet travels I have not yet found any pistons built like this (any make) but no-one shows a piston in it's component form, just changing the seals which isn't really helpful. The seal conversions I have seen for the HW55 are not using 'o' rings like this one, just a big rubber bung to replicate the size of the leather.

[T 20]

The piston that has come out of mine has:

Aluminium head
Double slotted steel body
Adapter for synthetic seal but that is literally just attached to the front of the head with a single screw as the leather ones are.

The body was screwed onto the aluminium head with a pin running right through presumably to stop it unscrewing itself. The pin is offset to allow for the steel catch bar running down the middle.

On my internet travels I have not yet found any pistons built like this (any make) but no-one shows a piston in it's component form, just changing the seals which isn't really helpful. The seal conversions I have seen for the HW55 are not using 'o' rings like this one, just a big rubber bung to replicate the size of the leather.

Could you weigh the remains of the piston to give me an idea of the overall weight of the alloy piston, please --- the gun serial number would also be useful.

I have heard of the 55 having a steel and aluminium piston before but never come across one.




All the best Mick