Prewar BSA double sear trigger problem

[stevegv8]

I have a side button underlever with the double sear trigger that's "broken". I realise someone might say unit might differ model to model?? Don't have serial or exact version info to hand right now.
How impossible would it be to find the parts I need?
It's away at repair at the moment so I don't know exactly what's been found to be the issue, but in short if I can find the complete unit to buy or equally difficult, borrow one to disassemble and copy. I have a skilled guy who will make a replica part from a pattern.
Equally a dimensional blueprint would probably work for him.

More info to follow when I've been to see the diagnosis but clearly going to be in need of the sear/trigger unit, ideally to copy and return.

Yours, probably up the creek
Steve

[trajectory]

It's all speculation until you get the condition report but there are a couple of places for spares, perhaps Knibbs & Protek are the ones that come to mind first. Your existing parts may provide a basis for repair or perhaps act as a source for dimensions should parts need to be made...?

Hopefully the creek won't turn out to be as deep or wide as you fear.

It will be interesting to see what they find as the cause of the problem, might even be repairable without too much trouble

[stevegv8]

It's all speculation until you get the condition report but there are a couple of places for spares, perhaps Knibbs & Protek are the ones that come to mind first. Your existing parts may provide a basis for repair or perhaps act as a source for dimensions should parts need to be made...?

Hopefully the creek won't turn out to be as deep or wide as you fear.

It will be interesting to see what they find as the cause of the problem, might even be repairable without too much trouble

Afternoon, I already tried all the usual places so copying or finding some one with one tucked away is about my only chance.
I get the impression a lump is broken off and missing or measurements could have been takenn

[Huttles94]

well oddly enough I do believe I have a spare double sear trigger in my parts box, Will check when I get home!

[Josie & John]

Hi Steve,

There are usually two small springs on these safety sears. I have recently discovered that as they are slightly different in length, a previous owner may have reassembled the springs the wrong way round, so this is worth checking before you fork out on a new unit.

Possibly not the cause but worth trying.

Kind regards,

John

[stevegv8]

well oddly enough I do believe I have a spare double sear trigger in my parts box, Will check when I get home!

That would be great thanks I might be a bit excited!

Steve

[stevegv8]

Partly to bump this up I'm wondering if this double sear type trigger is one type only or were there variations over the models for the period they were produced?
Finding one might be hard enough so hoping it's not a particular version I'm looking for.

I'm yet to explore John's spring suggestion so here's hoping.

Steve

[trajectory]

Steve, I know you are going to take a look at the two spring suggestion but have you had a report back to know if your example has a broken / damaged component? Maybe if you can get a picture up it might be of some help in sourcing parts if needed.

[Lakey]

Some information here that you may find useful ?

https://forum.vintageairgunsgallery....qs-2/#post-511

[stevegv8]

Steve, I know you are going to take a look at the two spring suggestion but have you had a report back to know if your example has a broken / damaged component? Maybe if you can get a picture up it might be of some help in sourcing parts if needed.

He (repair man) is looking into my options before I go back to see it and get clear info on it's issues, he is known for dramatic exaggeration but I took it to him because when I got it as a project I was told it had undisclosed problems in that some parts may be missing or broken.
Not having knowledge of the double sear trigger, I wouldn't have a clue if something was missing so I thought this was the route to go as a starter. If a solution is arrived at I may rebuild it myself.
Once he comes back to me with better info I'll go and suss it out myself so I'll know more about what I need or can do.
I hope I'll have a better understanding before too long.

Steve

[stevegv8]

Some information here that you may find useful ?

https://forum.vintageairgunsgallery....qs-2/#post-511

Lakey thanks, I was just looking at this for a second time and I see mine is the trigger on the right as I have the rivet (having retrieved every thing from my gun man, will update post further down) but I read this as that version has just one spring? Mine has the recess' to take upper and lower springs, both of which it has, although they are certainly non original as one is cut down with no nice flat and I feel they are too heavy too.
Did they omit one but leave the recess' avoiding a re-design?

Thanks

Steve

[stevegv8]

Ok I can update somewhat now.

Imgur link https://imgur.com/gallery/3JmKJVF shows pics relevant to details in this info.

First of all it's a project that's been waiting a few years and I finally decided while I work on something else, I would send it out to someone I know who claims expertise on the brand.
I had never looked into the guns parts at all but warned him it was supposedly with broken and incorrect parts and was someone's abandoned project and I wouldn't be able to recognise it's problems for myself so handed him a bag of parts.

During the life of this thread I had been thinking two sears would surely require two notches in the piston rod and as the parts were all loose in a bag I was fairly sure the rod had only one notch from memory.

So last night I was dragged out, and went through, Knibbs BSA & LJ air rifles and on page 68 I was able to familiarise myself with how my sear should be, additionally Lakey had show further up the thread the difference between the two types of double sear.
This - if you look through his link https://forum.vintageairgunsgallery....qs-2/#post-511 - suggests, if I understand correctly, that a second spring becomes omitted on my version? the one on the right.
However it did show two notches in the piston rod so my thinking was right and I needed to check this on my one.

So today I went over to get the run down on my fixers findings and now I can see that he meant the rear most sear is missing and the area has been dressed removing any roughness of a break or was it that it purposely removed? I say this because with only one piston rod notch (as I had thought he had missed this detail completely) was the piston changed at some point and they then felt a sear would need to go? it didn't latch up I was told so that's probably where it all had gone wrong maybe. Perhaps it would have done had the front sear been removed? . More importantly is whole the piston correct even?

I felt though that I wanted to take over at this point so I've brought it home for now, It's obvious that taking some time researching was what I should have done in the beginning but as I said I'm into another project at the same time. The spring pic in my link shows wire wheel swarf in the coils which is alarming by whoever is responsible, that area was reassembled when I collected.

I may now have a double sear set up sourced, so next do I need a piston, is it correct but with wrong rod? or do I just need the correct rod or again copy the rod if one can be loaned?

Starting to feel less worried and more intrigued now and enjoying the research although the problem is not yet sorted I'm hoping sorting the piston is the only remaining concern.

Steve.

[Lakey]

Hello,

My guess is that your gun has a later piston fitted with its single notch piston rod. In order to do this , the double safety sear has been adapted, and the second sear ground away.

Lakey.

[stevegv8]

Hello,

My guess is that your gun has a later piston fitted with its single notch piston rod. In order to do this , the double safety sear has been adapted, and the second sear ground away.

Lakey.

That makes some sense and I think that's exactly what's happened, as I mention in the post above, but it doesn't latch after their efforts. Only thing I'd say is the front sear and rod notch both look like they've been re shaped and maybe why it isn't working, the remaining front sear looks quite botched compared with the one in Knibbs picture.

I'm going to put it together without the spring to see how it marries up during cocking but the bit I want to see will be hidden in the trigger block no doubt.

Steve

[edbear2]

Hi Steve,

The reason the pinned one has one spring is that it only needs one, to see what is going on inside it's easy to use the trigger block pivot as a guide and mock up something if you have access to some tube / bit of box. This sort of thing;

https://www.flickr.com/photos/312284...7626485415532/

Or you could maybe make something to hold you action onto a base etc.

Here I set a CD unit on a BSA I modified at the height and position it would be to check sear engagement with a piston rod, so just attach a bit of tube or scrap cylinder to a base, then set up your trigger with a spacer so it's the right height and you will see exactly what is going on as the piston moves back, It is quite enlightening to see how the piston rod ramps over the sear / trigger and then latches when you do this.

The whole double sear system is a rare example of an unnecessary safety (the guns are safe with the tap open) attempt by BSA which was obviously not tested long term, as so many are seen that have been riveted up. When all is good it works well enough, but I doubt guns with the system working get the hard use a gun would have back in the day which obviously brought the problem to light to the dealers / factory.

Pretty much summed up by the fact that the factory "fix" was to disable the whole shebang....The problem getting them to work is also getting the spring balance correct, I have done two or three and it's a pain but can be done (I had a Juvenile which arrived with problems which took ages clipping springs etc. to get the right balance as springs are NLA).


ATB, ED