service mk2 piston

[SLUGGY]

Ive stripped down my service mk2 and found the piston to be very worn where the sear engages,so worn in fact that the metal is starting to break thru in one small patch.As im looking at getting another piston at least if not a new sear(i think thats what its called)is there any upgrade to consider here,any later pistons that will fit +maybe work better?Thanks

[TopDog]

Ive stripped down my service mk2 and found the piston to be very worn where the sear engages,so worn in fact that the metal is starting to break thru in one small patch.As im looking at getting another piston at least if not a new sear(i think thats what its called)is there any upgrade to consider here,any later pistons that will fit +maybe work better?Thanks

Hi

If you have pics, we can better understand the issue. If this bit is very worn other areas are likely to be very worn too.

Chambers don't list a piston but John Knibbs (or Mark) may be able to help.

However, if it really is only wear in the sear engagement region I'm sure that it could be repaired effectively but a competent gunsmith/welder/model engineer as a much cheaper option

Best of luck
David.

[TopDog]

Hi again

Have sent detailed e-mail with pics for the modified piston and "O" ring definition. The problem with BBS PM's is that one soon runs out of characters!

If someone has a reference for the article in Airgunner or Airgun World on using "O" rings in a Webley Mk2 Service I'm sure many would appreciate a nudge towards it! Mine had already been converted (original piston and ring still here of course!) but I am currently sorting out a small mod problem (25 yaers later!!).

Best of luck with saving a lovely gun!

Best wishes
David

[daveh]

I have seen a piston reclaimed by rotating it through 90 degrees and remachining the slot.This will give two "new" sear locations. down side is you can only do this once and the piston is lightened considerably.But it works!
Regards
Daveh

[TopDog]

I have seen a piston reclaimed by rotating it through 90 degrees and remachining the slot.This will give two "new" sear locations. down side is you can only do this once and the piston is lightened considerably.But it works!
Regards
Daveh

Yes, that would work but a bit extreme! If the damage isn't too bad it could be built up (welded!) and then the sear engagement notch machined in after filing/turning the repair to the true diameter. This would perhaps be less work and lead to a more original finish!

ATVB
David

[gedfinn 2]

Yes, that would work but a bit extreme! If the damage isn't too bad it could be built up (welded!) and then the sear engagement notch machined in after filing/turning the repair to the true diameter. This would perhaps be less work and lead to a more original finish!

ATVB
David

I thought that the previous Idea of maching a new slot at 180 degrees was a good & simple solution.
I would however Tig weld it up , file/turn ( Button Ha ha) to shape & case Harden using
Kasenite ( I still have half a tin ) Even though it has been banned.

I have done a number of pistons like this, The worst for wear, And I have done a number are the older Webley Falcons, I think they must have forgotten to harden them at the Factory ?

I would say that 95% of all worn airgun parts can be recovered by the above, Especially as parts are becoming scarcer,
I can repair the above, Or indeed any worn gun part, But not in the next 2 weeks, Cheers, Ged.

[SLUGGY]

good point about the case hardening,id not thought of that.for what its worth ive used sugar in the past worked well on motorbike kick start cotterpins.

[TopDog]

I thought that the previous Idea of maching a new slot at 180 degrees was a good & simple solution.
I would however Tig weld it up , file/turn ( Button Ha ha) to shape & case Harden using
Kasenite ( I still have half a tin ) Even though it has been banned.

I have done a number of pistons like this, The worst for wear, And I have done a number are the older Webley Falcons, I think they must have forgotten to harden them at the Factory ?

I would say that 95% of all worn airgun parts can be recovered by the above, Especially as parts are becoming scarcer,
I can repair the above, Or indeed any worn gun part, But not in the next 2 weeks, Cheers, Ged.

Hi Ged

Will bear that in mind when I find such a problem!

ATVB
David