Webley Hawk Mk 3 piston wanted.

[Geoff555]

Hi all. I am looking for a Hawk MK 3 piston, good price paid. I know I have put a wanted notice before, but ended up with a complete rifle that was just too good to break.
Thank you.
Cheers.
Geoff.

[T 20]

Hi all. I am looking for a Hawk MK 3 piston, good price paid. I know I have put a wanted notice before, but ended up with a complete rifle that was just too good to break.
Thank you.
Cheers.
Geoff.

Hi Geoff

Is it a case of you not having a piston at all, or is your piston damaged ?

I only ask as the Hawk pistons are very soft metal and can be welded up and machined back down if needed.




All the best Mick

[Geoff555]

Hi Mick not as soft as a BSA meteor perhaps. Thank you for the advice. I wanted one to modify and didnt want to risk spoiling the one in the gun, silk ear into a sows a**e or something like that.
Cheers.
Geoff.

[T 20]

Hi Mick not as soft as a BSA meteor perhaps. Thank you for the advice. I wanted one to modify and didnt want to risk spoiling the one in the gun, silk ear into a sows a**e or something like that.
Cheers.
Geoff.

Hi Geoff

I do hope you're not trying to modify and update a classic British Air Rifle --- I do find that kind of vandalism disgusting and feel it should not be entertained it the gentlemanly surroundings of Collectors corner.


But if you do want to be naughty, you could MIG shut the piston ring grooves and then machine the piston to this sort of shape

http://i1138.photobucket.com/albums/...ps9260f2ca.jpg

And then I suppose you could fit a 25mm Weihrauch piston seal with a Walther LGV 2012 bearing fitted behind it.
http://i1138.photobucket.com/albums/...psce13d0d8.jpg

If you did this correctly you could end up with a 25mm X 80mm bore and stroke, which is just 1mm short of an early HW77's stroke.
Then I suppose you could drill and tap the back block at 5/16" UNF so that you could screw in a nice long spring guide.
http://i1138.photobucket.com/albums/...ps620e0c38.jpg


Perish the very thought of doing such a thing.


All the best Mick

[ggggr]

Just a thought Geoff. not got anything with me to compare BUT
I know that the Hawk Mk1 cylinder and piston are shorter than the Mk2 or Mk 3----BUT as the leather or Ptfe piston washer on the Mk one is held on by a rivet, guessing you could make up a piston head to suit and fasten it with a screw?
That might now give you the option of a Mk1,2 or 3 piston to play around with.

[Geoff555]

Hi Mick actually I think that I am doing it a favour and saving it from the scrap bin, I really do hate to throw things away. Red rusty, all the pivots oval, cylinder worn and oval, rear cylinder block holes for the retaining pin torn. I haven't checked but I suspect that the barrel 'might' be bent, it certainly points to the left. I have spent hours with Webley piston rings of all sorts and many 'O' rings etc.
Best 7 FT/LBS and worst just about 6 FT/LBS and dying on it's a++e. Not counting the trigger.

I no longer have any kind of workshop, only the living room floor and the kitchen unit top.It is a real pain to have to find other people to do stuff. It is a balancing act between running a car food bills etc. much like many other people. Not complaining at all it is how it is.
Many thanks for the tips and thoughts, all useful things.

Thank you also Guy, I will get there and I will be back and let you know the progress.
Cheers.
All.
Geoff.

[T 20]

Hi Geoff

Try running an O ring in the front piston ring groove and a Webley ptfe ring in the second groove to act as a bearing.

It is also worth sleeving the transfer port down from 4mm to 2.5mm --- this makes a hell of a difference to the power output and firing cycle.





All the best Mick

[Geoff555]

Hi thank you Mick, I have tried the 'O' ring and ptfe ring but I think that the only thing I can think of doing is to pack the ptfe ring out because there is a .006" gap betwixt the piston and bore and the ring is somewhat slack. Heck 2.5mm for the TP goodness that is small, I will give it a go.
Thanks again.
Cheers.
Geoff.

[T 20]

Heck 2.5mm for the TP goodness that is small, I will give it a go.
Thanks again.
Cheers.
Geoff.

Never fear Geoff

The transfer port of the Vulcan is 2.5mm and that flows plenty of air through it.

With an 80mm stroke the standard static compression ratio is 195:1 with a 4mm port.

Sleeve the transfer port to 2.5mm and the static compression ratio rises to 494:1.


Trust me it works.





All the best Mick

[Geoff555]

Hi Mick, I do trust you, I do, I do honest. Its myself I have doubts about.
Cheers I will let you know how it goes.
Geoff.

[Geoff555]

Hi all this is a quick one, will be having a break from this thing for a week, 2.5 mm TP, tried 4 different springs, hard, soft,long, short and it makes absolutely no difference what so ever. Minimum 6.2 and Maximum 7.1. HUMPH! I have a couple of ideas to try yet, but it will probably be the end of next week before I will have the bits and time.
Cheers all.
Geoff.

[T 20]

Hi all this is a quick one, will be having a break from this thing for a week, 2.5 mm TP, tried 4 different springs, hard, soft,long, short and it makes absolutely no difference what so ever. Minimum 6.2 and Maximum 7.1. HUMPH! I have a couple of ideas to try yet, but it will probably be the end of next week before I will have the bits and time.
Cheers all.
Geoff.

Strange one Geoff

The Hawk cylinder is screwed onto the breach and sealed with thread sealer, if this breaks down you can get leakage to the forward stock mounting holes so more spring creates more leakage.

I've had this problem with a Hawk cylinder in the past, if it is leaking it should be possible to seal it with Loctite 271.




All the best Mick

[Geoff555]

Hi Mick ta mate, I have removed the plug and cleaned it up and lock tighted it up some time ago, it was something that Guy suggested. Something keeps telling me it's a piston seal issue, but thats only a gut feeling. Not exactly scientific !!!
Going to spend some quality time sorting the brakes on a 1950 Bedford bus. Will come back refreshed.
Cheers.
Geoff.

[Peter Dunkley]

Hi I am reliably told there is such an animal on that Bay.

[Geoff555]

Hello Peter thank you kindly for that, I am bidding on it but have not said anything yet until I have won it, or not.
Funny you should mention that Guy, when using a bigger spring, just to see basically what difference it would make, the readings went down as if they had fallen off a cliff. Gap between barrel and breech seal of 1/16" .Barrel had moved!!! ( IT was OK before.) Lock tighted and secured. The barrel pointing to left slightly was the jaws a bit bent, they arnt now. Just remembered that the pivot pin was sheared when I first had it.
Thank you all, the saga will continue.
Cheers.
Geoff.