BSA Improved Model

[trajectory]

On an improved model B I used an Airsporter spring cut to give about 1.5" pre load. The end was ground & polished up, might give you a starting point?


Cylinder/barrel & trigger block might be an original pairing despite how they seem to have aged differently; if the steel composition isn't the same perhaps it might account for the different look?

It might never look mint but It looks like one to hang on to

[jirushi]

On an improved model B I used an Airsporter spring cut to give about 1.5" pre load. The end was ground & polished up, might give you a starting point?


Cylinder/barrel & trigger block might be an original pairing despite how they seem to have aged differently; if the steel composition isn't the same perhaps it might account for the different look?

It might never look mint but It looks like one to hang on to

That's great to know, thank you.
Does your Improved Model B have an old leather seal, or a replacement? I have a feeling that the shallow cup ones from Protek will work best.
Good point on the possibility of different metals giving different looks.
Here is how it looked when I bought it:
(very dark stock, due to all those years of oiling and dirt, I suppose. And faded finish on the trigger block)

[trajectory]

That's great to know, thank you.
Does your Improved Model B have an old leather seal, or a replacement? I have a feeling that the shallow cup ones from Protek will work best.
Good point on the possibility of different metals giving different looks.
Here is how it looked when I bought it:
(very dark stock, due to all those years of oiling and dirt, I suppose. And faded finish on the trigger block)

Hi, the piston washer on that model B might be an original one. It looked intact & was supple so I didnt replace it & it seems to work pretty well. I tend to make them if I need them. It's a bit of fun if you have the time & the bought ones sometimes need conditioning & fitting so I end up fiddling with them anyway. Your woodwork looks to have cleaned up well. Some stocks have marks & large patches which are almost black in colour & are really deeply ingrained. They can be got out but it's often a long job to do so. Yours looks to be pretty good.

[jirushi]

Hi, the piston washer on that model B might be an original one. It looked intact & was supple so I didnt replace it & it seems to work pretty well. I tend to make them if I need them. It's a bit of fun if you have the time & the bought ones sometimes need conditioning & fitting so I end up fiddling with them anyway. Your woodwork looks to have cleaned up well. Some stocks have marks & large patches which are almost black in colour & are really deeply ingrained. They can be got out but it's often a long job to do so. Yours looks to be pretty good.

Thank you trajectory.
One side of my stock is a bit darker than the other; I must have worked less hard on the darker side! It was a lot of rubbing with the steelwool. In any case it's better than how it was. Making leather piston seals is something I should learn. For now I will order one from Protek.

Does someone know how to get the phosphor bronze piston rings off correctly?
I have tried putting a small tool in the gap of the rings, but this way I will deform the rings, if I pull them out. Perhaps that's the only way.
I would rather have a good leather seal and no rings, than both (as I have seen that air leaks past the rings anyway).

[trajectory]

Piston ring removal, Hopefully someone better qualified than me will be along to give some advice. In the meantime I think there might be something on YouTube, hopefully, have a look for servicing a Webley senior or mk11 Service air rifle as they have phosphor bronze rings. Only thing is if they are servicing them they may not remove them for re use or they might already be broken. They are brittle so in motor engineering you used to push a ring from one side & wiggle a thin shim in the gap that appears opposite, then you move around 120 degrees & repeat, then another 120 degrees till you have three shims in place holding the ring open. Then wiggle the three around till they are at 90 degree spacings, then insert a fourth one. The shims are small in width & very thin but strong enough to hold the ring open , just enough to slide off the piston. Well that's one way old cars were stripped down. Same might work for your BSA but wait till someone else gives you another idea. Maybe thin but strong plastic might be enough, cut from packing material?

BUT they are BRITTLE so research it well, & choose whichever method you think is best for you. Once broken its too late to go back. It's your decision.

[edbear2]

Piston ring removal, Hopefully someone better qualified than me will be along to give some advice. In the meantime I think there might be something on YouTube, hopefully, have a look for servicing a Webley senior or mk11 Service air rifle as they have phosphor bronze rings. Only thing is if they are servicing them they may not remove them for re use or they might already be broken. They are brittle so in motor engineering you used to push a ring from one side & wiggle a thin shim in the gap that appears opposite, then you move around 120 degrees & repeat, then another 120 degrees till you have three shims in place holding the ring open. Then wiggle the three around till they are at 90 degree spacings, then insert a fourth one. The shims are small in width & very thin but strong enough to hold the ring open , just enough to slide off the piston. Well that's one way old cars were stripped down. Same might work for your BSA but wait till someone else gives you another idea. Maybe thin but strong plastic might be enough, cut from packing material?

BUT they are BRITTLE so research it well, & choose whichever method you think is best for you. Once broken its too late to go back. It's your decision.

The above is bang on advice, all depends on the grade / type of bronze used (Oilite thro PB2 or 660 if you are lucky etc.) as some are more forgiving, I use both the shim method and also the spring the ends with thumnails gently until clear.....both can be risky!

ATB, ED

[jirushi]

Thank you very much for your advice, gents.
I will remove the rings very carefully soon.
Might try with rings and a new leather seal first; if shooting behaviour and power are good, then perhaps it will be best to leave the rings alons.

Does someone know what power I should expect with this .177 specimen? I read on the VAGF: about 725 ft/s. Not sure with which pellets though.
I guess about 9 to 10 ft/lbs in a very good example?

[Kuyajonathan]

Piston ring removal, Hopefully someone better qualified than me will be along to give some advice. In the meantime I think there might be something on YouTube, hopefully, have a look for servicing a Webley senior or mk11 Service air rifle as they have phosphor bronze rings. Only thing is if they are servicing them they may not remove them for re use or they might already be broken. They are brittle so in motor engineering you used to push a ring from one side & wiggle a thin shim in the gap that appears opposite, then you move around 120 degrees & repeat, then another 120 degrees till you have three shims in place holding the ring open. Then wiggle the three around till they are at 90 degree spacings, then insert a fourth one. The shims are small in width & very thin but strong enough to hold the ring open , just enough to slide off the piston. Well that's one way old cars were stripped down. Same might work for your BSA but wait till someone else gives you another idea. Maybe thin but strong plastic might be enough, cut from packing material?

BUT they are BRITTLE so research it well, & choose whichever method you think is best for you. Once broken its too late to go back. It's your decision.

Echo trajectory's advice re ring removal. Late 60's early 70's rebuilt number of villiers 2 stroke m/cycle engines as a well as few 4 strokes. Used the shim method to change the piston rings, owners manuals had v detailed info on checking piston ring wear, measure gap in bore! Quality and lubricants gave impression that wear was normal and replacement the answer. some rings had chamfered edge as wel,also oil control rings as mentioned. ring ends varied from square to angled , I recall stepped ends on one or two, as well as pegs in groves to hold in place, stepped 120 degrees with 3 rings. Very brittle and required careful handling.
If this was a 'mod' by a skilled owner, looks like good work those cutting groves on a lathe, where would the rings have come from? Pro priority ready made from another application? Or if home made takes the skills to
Changed ring in my (then) 10-15 yr old Webley senior in late 60's when acquired it, along with new spring. No reason, apart from cos I could !

[edbear2]

Echo trajectory's advice re ring removal. Late 60's early 70's rebuilt number of villiers 2 stroke m/cycle engines as a well as few 4 strokes. Used the shim method to change the piston rings, owners manuals had v detailed info on checking piston ring wear, measure gap in bore! Quality and lubricants gave impression that wear was normal and replacement the answer. some rings had chamfered edge as wel,also oil control rings as mentioned. ring ends varied from square to angled , I recall stepped ends on one or two, as well as pegs in groves to hold in place, stepped 120 degrees with 3 rings. Very brittle and required careful handling.
If this was a 'mod' by a skilled owner, looks like good work those cutting groves on a lathe, where would the rings have come from? Pro priority ready made from another application? Or if home made takes the skills to
Changed ring in my (then) 10-15 yr old Webley senior in late 60's when acquired it, along with new spring. No reason, apart from cos I could !

Rings are easy to make, have actually made some for a vintage motorbike bike that were a funny size / NLA (you use CC Cast iron bar stock).

Simple description.......

1........Reduce dia of bar to size needed for ring O.D. on lathe.
2........Drill then bore hole to give correct I.D. needed
3........Part off with cutting tool to get correct thickness needed.
4........Cut through then file to get ring end gap required (usually specced by pushing ring into bore with piston and measuring)

In the case of your piston, just a simple grooving tool made the slots, you can make your own out of tool steel stock and a grindstone, another thing taught at school, but these days everything can be got in carbide disposable from the legions of supply places catering to the home machinist / hobby industry.

ATB, ED