My Mercury Ratting Rig

[evert]

Well, I've found a some other problematic tubes over the years:
-bulges in Supersport tubes that let lubricants pass the seal.
-a ridge, probably made of brazing leftovers that interferes with the seal the last cm of a HW80 tube.
-a similar ridge that chews up seals near the bottom of a Webley Victor tube

[T 20]

eash, that's never going to shoot nice.

messy bodge idea: machine a nice flat disc to fit the cylinder bore, smatter gobs of jb weld on one side, insert it with the piston to keep it true, stick the mainspring and block in there and tighten it all up to ram the JB weld into all the holes, and hopefully force as much air out as possible. the disc stay in place permenantly, forming the new cylinder end. When all set, drill a new port, and hope. I mean, it can't really be worse, can it ? Should only cost you 2mm in stroke/ tp length.

No need to worry about it now, Jon, I have a cunning plan.

image.jpg

After great thought and much measuring, I've decided to graft a HW80 breech and barrel onto my Mercury cylinder.
My thinking behind this is that in order to make a proper job of this Mercury cylinder I'd have to take out the breech plug, build it up with weld, machine it back down and then weld it all back in the cylinder.
Fitting a HW80 breech forks is about the same amount of work but I'd gain a proper breech hinge bolt a proper 5.5 barrel and the ability to fit a decent set of steel open sights if I want to.






All the best Mick

[TonyL]

And it's looking like you may have got fixed up, Mick.

This is going to be interesting.

[T 20]

This is going to be interesting.

There's much measuring and drawing needs to be done before I get near the lathe with this one, Tone.

I also need to work out how to mount everything in the lathe and make fixtures, fittings and jigs to do the job properly so this will slow my progress down to a crawl, but I'll update the thread as and when there's anything to see.



All the best Mick

[Shed tuner]

No need to worry about it now, Jon, I have a cunning plan.

image.jpg

After great thought and much measuring, I've decided to graft a HW80 breech and barrel onto my Mercury cylinder.
My thinking behind this is that in order to make a proper job of this Mercury cylinder I'd have to take out the breech plug, build it up with weld, machine it back down and then weld it all back in the cylinder.
Fitting a HW80 breech forks is about the same amount of work but I'd gain a proper breech hinge bolt a proper 5.5 barrel and the ability to fit a decent set of steel open sights if I want to.

All the best Mick

Yeah, I agree, at least when you are finished it'll be way better than the original design

[crowbar]

I have harboured the idea of grafting one to a smaller comp tube for a long while,my idea is to sleeve it over the cylinder
and weld it. Holes can be drilled in outer tube and spot weld through was one idea and (hopefully) won't distort the comp
tube.

[evert]

After great thought and much measuring, I've decided to graft a HW80 breech and barrel onto my Mercury cylinder.

It will be a bit like the old Webley Hawk, with its large breech forks and small diameter tube.
Only bigger, and without any Webley parts

[T 20]

Yeah, I agree, at least when you are finished it'll be way better than the original design

It'll get rid of a Weihrauch barrel from my spares pile as well, Jon.

The good points of this conversion is that the Mercury and HW80 use about the same length transfer port, and the distance from the breech face to the cocking lever pin on both guns is about the same.
This means that if I keep the HW breech face in the same place as on the Mercury then the BSA cocking arm should land in about the right place on the cylinder.



All the best Mick

[T 20]

I have harboured the idea of grafting one to a smaller comp tube for a long while,my idea is to sleeve it over the cylinder
and weld it. Holes can be drilled in outer tube and spot weld through was one idea and (hopefully) won't distort the comp
tube.

There's a few problems with doing it that way, the plug welds would no doubt be strong enough, but they wouldn't seal the cylinder end, so you'd end up brazing it as well.
There's also a good chance that you'd distort the tube as it's only thin walled, plug welding to a thin walled tube also has a chance of over penetration, so the tube would need honing to size after welding.

What I'm aiming to do is to machine 9mm of the HW plug down to a very slight interference fit in the Mercury cylinder then do a full radial MIG weld round the joint.
In doing it this way the tube is kept round by the plug, the heat from the weld is soaked up by the plug and the joint is sealed.
Another bonus of doing it this way is that as the radial weld cools it will tend to shrink the tube onto the plug at the joint.




All the best Mick

[Shed tuner]

whilst you have it apart, howsabout sleaving down to 26mm, fitting an HW seal & hw95 piston, should be great with around 75mm of stroke.
Along with the HW 80/95 barrel... Then just the trigger to sort.. reckon you can graft a rekord in there ?

[T 20]

It will be a bit like the old Webley Hawk, with its large breech forks and small diameter tube.
Only bigger, and without any Webley parts

No, Evert.

I'll be taking the HW breech jaws down to the Mercury cylinder OD.

My plan is to fill the HW jaws with a lump of steel plate welded in at the very front of the jaws then machine the jaws and steel down from 34mm OD to 32mm OD.
Filling the jaws in this way will make mounting the jaws in the lathe easier in order to machine down the plug to fit inside the cylinder.
Mounting breech jaws in the lathe is a real pain with either a three or four jaw chuck without having the forks filled in.
The front of the lump of steel can also be drilled to use a revolving centre, giving me more options on mounting in the lathe.
Once the lump of steel in the jaws has served its purpose it can be cut out and the welds machined down.



All the best Mick

[T 20]

whilst you have it apart, howsabout sleaving down to 26mm, fitting an HW seal & hw95 piston, should be great with around 75mm of stroke.
Along with the HW 80/95 barrel... Then just the trigger to sort.. reckon you can graft a rekord in there ?

Why not just move the silly tile holes forward on a 95 to whatever stroke you fancy, Jon --- or just long stroke a 99 by using a 26mm SMK seal.

A Rekord in a Merc is a bit of a none starter as the back sear would have to poke out of the top of the back block.
I quite like the classic lines of the Airsporter and Mercury back blocks and the triggers can be set sweet enough for me.
By coincidence I've just been machining a couple of new ally Mercury trigger blades today, but I'm making them a little wider than the originals for a better feel.




All the best Mick

[crowbar]

I think it will crack with a bit of use,perhaps after you press the two together you could radially drill through comp
tube wall into the 9mm of plug and spot weld them and seal comp tube after with JB Weld.

To hold the jaws in the chuck a split bush might do the job.

[T 20]

I think it will crack with a bit of use,perhaps after you press the two together you could radially drill through comp
tube wall into the 9mm of plug and spot weld them and seal comp tube after with JB Weld.

To hold the jaws in the chuck a split bush might do the job.

The last one I welded radially hasn't split yet. :-

https://www.airgunbbs.com/showthread...29#post5782529




All the best Mick

[crowbar]

I followed that thread and have read all 18 pages again and I thought the joint on the 35 was in the balance and that is two tubes and the Mercury is a single tube,but I was wrong on the 35 and I hope the Mercury is strong enough.

Keep going anyway I like to see other peoples creations as much as making my own stuff as it broadens the mind and you
have made some good ones,I like your B2.

Cheers Crowbar