BSA Cadet Major breech seal.

[pcusername]

How the hell does this fit in? I've already ruined 2 at £6.80 a throw.the measurements of the actual breech where it goes are 12.3 mm od and 8 mm id.I soaked the first one for a week in oil and couldn't even get a 5 mm drill shank through it,it remained rock hard.Further experimentation with it by drilling it out left the wall to thin to be of any use.Bought another,it was the same,saw some advice to boil it to soften it up,it softened ok but shrank and broke up trying to fit it.I could rip the leather in pieces it deteriorated that much with the boiling.
Are there any alternatives?O-rings don't worth due to the angle needed.I'm thinking of getting some ptfe tubing and making one out of that.Any ideas?

[johnbaz]

I made one by sticking two pieces of 4mm leather together, I fitted it dry then oiled it and left the breech open for a couple of days so as not to squeeze out the oil before it could penetrate


This was before it had swollen




John

[Phil Russell]

Yes ... not easy.
If you can find some polythene tubing or rubber tubing of the correct size (12mm od, 8mm id) it is possible to make your own by cutting off a short length.... cannot remember but maybe 1cm is plenty.... fit into the seal recess then use a sharp scalpel blade to cut the tubing just proud of the breech face. I have used a thin shim with a 12mm hole in it over the breech as a guide ... for shim read bit of beer can.

For tubing, some hardware shops sell it, or home brew shops, not sure about places like B&Q. Some car fuel or heating system hose is OK as well.

Cheers, Phil

[ggggr]

How the hell does this fit in? I've already ruined 2 at £6.80 a throw.the measurements of the actual breech where it goes are 12.3 mm od and 8 mm id.I soaked the first one for a week in oil and couldn't even get a 5 mm drill shank through it,it remained rock hard.Further experimentation with it by drilling it out left the wall to thin to be of any use.Bought another,it was the same,saw some advice to boil it to soften it up,it softened ok but shrank and broke up trying to fit it.I could rip the leather in pieces it deteriorated that much with the boiling.
Are there any alternatives?O-rings don't worth due to the angle needed.I'm thinking of getting some ptfe tubing and making one out of that.Any ideas?

Someone made me some lengths of tube by drilling some ptfe rod, after I read about it in an AGW.
Re the leather washers. The ones I have fitted, I filed/sanded them dry and then fitted them and put some oil on after. You are not supposed to boil leather or use hot water although I have used it in the past to form small washers. If you buy another washer, then I would find a bit of bar with the right OD for the ID of the washer and put a taper on it and then soak the washer in warmish water and work it onto the shank as is softens. Once you have it on the shank, leave it to dry and harden, then file/sand the OD of the washer to the right size and put a slight lead in on it.

[Phil Russell]

To add to Guy's post .... if you do get a too tight leather one and do not want to go the warm water route, you can treat it with leather softener as sold for shoes. I once had a small bottle but later found it was only now available as a spray. But it is only isopropyl alcohol. Works well.
Cheers, Phil

[pcusername]

After a little thought I came up with this,it's quite successful actually.I filled the seal groove in the breech with thermomorph moldable plastic and while still soft pushed an 8mm id x 2mm cs viton o-ring in to form the shape needed due to the angled breech.Closed the breech to seat the o-ring a couple of times and all seems to be well.

[DCL_dave]

That looks like a neat solution. Have heard of similar using clear silcon sealant to bed the O ring on

I made a jig for making leather breech seals for the cadet and cadet major...so, if need be, pm me your address and I'll pop a few leather breech seals in the post for you.

[DCL_dave]

Forgot to say...

The trick with an oversize cadet leather breech seal is to mount in on the shank of an 8-8.5mm drill bit then put the drill bit in your drill backwards and work down OD to required size, about 12.5mm, leave it on the shank, dip it in lukewarm water for a minute or two, roll in in a hard surface a few times and leave it to dry on the shank, this will set the centre size so that you can just push the seal in, hammer it home and trim to size.

[DCL_dave]

How the hell does this fit in? I've already ruined 2 at £6.80 a throw.the measurements of the actual breech where it goes are 12.3 mm od and 8 mm id.I soaked the first one for a week in oil and couldn't even get a 5 mm drill shank through it,it remained rock hard.Further experimentation with it by drilling it out left the wall to thin to be of any use.Bought another,it was the same,saw some advice to boil it to soften it up,it softened ok but shrank and broke up trying to fit it.I could rip the leather in pieces it deteriorated that much with the boiling.
Are there any alternatives?O-rings don't worth due to the angle needed.I'm thinking of getting some ptfe tubing and making one out of that.Any ideas?

Re. bold type above...that is because that advice was wrong, do not cook your leather!...

Seriously, lukewarm water only, or even cold water, just leave it to soak for as long as it takes...