28mm piston washer (BSA Mercury)

[Shed tuner]

Just stripped my Mercury, it has the modern o-ring ally head. I want to replace it with something more efficient, i.e. a regular piston washer. I have a lathe, so can make up a new piston head, but I need a suitable donor washer, in the region of 28mm OD to stick on - any thoughts please guys ?

Cheers,

JB

[Rich]

What material do you want, teflon or similar?

Rich

[Shed tuner]

To be honest I wanted to use a stock piston washer (from another gun, obviously), and just re-machine the piston, or a new piston head, to take it.

I guess one alternative option would be to machine a T,R,Ribb style 1 piece piston head/washer out of something like PTFE ?

I've just found that the FWB sport/BSA Supersport washers woudl fit the cylinder fine, but the fitting woudl require me to machine a muge hole in the face of the piston, and unfortunately there doesn't seem to be enough material to work with

Cheers,
JB

[Shed tuner]

any ideas please ?

[Rich]

I've got an offcut of 9mm thick teflon or hard nylon material. It's thick sheet not bar stock but there's enough for you to have a go at making probably three or four at 28mm diameter if the first effort doesn't work.

Send your home adress to my email if you'd like it posted.

Rich

[baz]

Turn one out of PTFE, then when fitted dry fire a couple of times (I know it sounds horrendous thing to do) as it will size it

Baz

[Shed tuner]

Rich, thank's but I think the material might be too hard..

Baz, makes sense, just got to find some now..

Cheers,
JB

[Rich]

Trust me JB, having seen plenty of synthetic washers I don't think it will be.

Rich

[Wheres me dummy.............]

Don't know if it helps but i got a washer straight out of my "o" ring box for my Meteor.

I run an engineering company that sells and repairs commercial espresso/cappuccino machines,and we have every size of "o" going - so if you need some,give me approx size(s) and i'll post them to you FOC.
(That goes for all bbs members)

Mark

[Shed tuner]

Trust me JB, having seen plenty of synthetic washers I don't think it will be.

Rich

In that case Rich, will email you - thanks

Caisterboy, the current arrangent is an o-ring. I want to ditch it and replace it with a "parachute" type washer, as these are more efficient and seal better. The crap sealing of the o-ring design is why BSA need to have a "buffer washer" bedind the piston head, to soak up the impact of the piston slamming into the end of the cylinder

Cheers,

JB

[ora8i]

Have a look at maccari's site he has a range of seals.

http://www.airguns.citymax.com/page/page/251485.htm


Ora

[Shed tuner]

The PTFE ones that Terry 'wheres me molegrips...just nip it up' Robb does are actually quite good to be fair........

I agree, but he doesn't still do them does he ? Will call him