Lg Siler lock problem?

[Bigmon]

I bought a used Siler lock that needed a main spring and a fly.  After I installed the parts it seemed to work ok, but was really a hard push on the sear arm.  It is not yet in a gun.
Had it apart inletting in a stock, and now I can only get it to trip about 1 in 10 times, in my hand.  Still don't have the trigger started, but I want the lock to trip once I start that step.
It must be really close to going?  My question is, do I hine the sear tip, or the tumbler notch?  Or neither??
I never messed much with locks like this??
Any help is appreciated??

[rich pierce]

If it’s a real hard push on the sear arm, there are lots of possible causes. I’m sure you’ve ruled some of these out already.
1) The sear does not move freely when the sear spring is disengaged. If so, sear bolt is too tight or the sear is too thick to move freely under the bridle.
2) the moving arm of the sear spring is long and it’s up against the boss of the sear instead of on the arm.
3) the sear arm top surface and the end of the sear spring are not polished or oiled.
4) the full cock notch of the tumbler is cut at an angle that is not pointing directly at the axle of the tumbler. If it’s pointing to the left of the axle, the sear has to pry the tumbler slightly clockwise before the sear slips below the notch. In that case you’re fighting the mainspring when trying to release the sear.

If you’re experiencing release from full cock but it gets stuck in the half cock notch, that’s a different issue.

[EC121]

Hold the lock nose down vertical with the mainspring removed.  Go to full cock then push on the sear bar.  If the hammer moves back(up) before dropping ,the full cock notch isn't right.  It should drop without moving backwards.

[Bigmon]

Thanks guys, will try all suggestions and get back.
The sear is free, but I'll check that spring length.
Also, will try the method with he spring removed.
I just bought that spring and it seemed to fit perfrct, but it is also very strong.  Could it be too strong?
Thanks again, will get back

[Steeltrap]

Don't mess with the mainspring until you follow the instructions the above fellows have provided. If your mainspring needs any work, they will advise you with correct information.

[Bigmon]

I cannot see any upward movement of the cock when tripping the sear with the mainspring removed and the lock front down in a verticle position.  It seems to trip ok.
But then I used down pressure on the hammer with my left hand, while pressing the sear, and it will not trip.
I took the fly out to get a better look.  While I am trying to trip it it seems there is the slightest "notch" in the tumbler full cock notch.  Just a very small little lip?
The sear spring length seems ok as it is not hard to depress at any time, and is just short of touching the screw boss on the sear?
Should I attempt to remove that tiny lip??  If so, with a stone or file??
Thanks as always.

[Steeltrap]

Can you post a picture?

[B Kauffman]

I would pull the tumbler out and use a diamond file (since it is hardened or it should be) and remove that small lip you have found and make the full cock notch proper size to meet the sear tip and keep in mind the correct angle. I'd be careful to to make it too shallow that it isn't safe.
Sounds to me like that you've ruled most things out, so the sear tip to full cock notch work should do it

[Bigmon]

Here are a couple pics that may help?  Hope so.

[Bob Roller]

The full cock position on the tumbler should be with a degree or two from vertical and the lower limb of the sear spring should be JUST short of contacting the sear behind the area of the sear screw and put pressure on the sear.
Bob Roller

[Bigmon]

Not to confuse this anymore, but perhaps you can tell by the photos the entire surface of the sear is in contact with the lock plate?  Though pretty smooth and polished, shouldn't the actually be a am area where it pivots at the sear screw that holds the rest of the sear just slightly off the plate and allows it to pivot more freely?
I bought this lock online used.  It seems pretty good for the most part, but I think it might have been a kit someone attempted.  Although I was told it was a "Davis" Siler?  I have had a Davis Competition Siler on a rifle since the mid 90's and it has been a fine lock.
Thanks to all for the suggestions and knowledge.
I'll keep messing with this until I get it right.  Trying to learn all the time.

[rich pierce]

Plenty of flintlocks and the majority of locks used in America lacked the “bearing” ring on the sear body. It’s a nice feature but if plate is case hardened like on originals, I’m not sure it helps performance. Some features are “improvements” found on best quality later locks but there may be plenty of other features contributing to high performance on those locks. Like painting a race car red might not actually make it faster, but it looks good. And when cast in place and not well finished, it’s had for me to believe that bearing ring helps. One person’s guess.

[Steeltrap]

Ok. Just to make sure we are "on the same page" here, I took your pic and for clarity, just added in some description.

So:

---When you say "The sear is in contact with the lock plate" the sear arm, is rubbing against the lock plate where I have the arrow pointed?

---If you loosen the Bridle screw that holds the sear in, does that allow the sear arm to move more freely? (That's pretty typical. I've made new screws with more precise thread depths so when the screw is tightened, it doesn't jam the Bridle into the sear arm)  Or, if you tighten that screw down does it jam up the sear arm?

---And lastly, that "notch" in the full cock notch on the tumbler.....There should be no notch there. If you could post a close up pic of the tumbler (out of the lock) so the picture angle shows the notch, that would also be helpful.

(Unless of course, you have removed the notch and all is working well)

[B Kauffman]

If the bridle is squeezing down against the sear and not allowing it to freely pivot from the squeeze, Ive taken a file to the bottom side of the screw so the threads bottom out in the lock plate itself but while taking the underside of the head off (what I colored  yellow) will essentially make the screw body longer and not squeeze down the bridle into the sear.

[Bigmon]

Firstly, I want to thank you all for taking your time and sharing your knowledge regarding this lock, and my need for help.
I am attaching a couple pics that you may be able to see my problem.  The angle of the notch does not appear to me to point at the center of the tumbler axis?  However the way it appears would make me believe it would fire more easily.  In fact perhaps not hold on full cock at all.
But that is not the case?  I did "stone" that notch a little, being afraid to go too far?  And I was able to trip it 2 out of 4 times.  Perhaps just a little more honing?  I do not have a diamond file.
There seems to be a notch in the notch or ledge that make it so hard to get the sear to come away from the tumbler?
Also, I am not pinching the sear by over tightening. I always make sure it moves freely.  However if I did tighten it down it would pinch the sear.  I like the idea of filing the underside of the screw head.  Might give that a try once I get this thing functioning.
Hope you can tell by these pics?

[EC121]

Those parts are cast and sometimes there is a little casting flaw in the notches.  A little more stoning might help.  In the event of a mistake tumblers are replaceable.  Also take a look at the sear point.  I have seen them too sharp. That makes it catch the lip even more.

[Bigmon]

I was going to ask about the sear point.  It is pretty sharp and maybe if I just rounded the edges a little it might slip away easier.
In either case "easy does it" I would think??
Thanks again to all.

[smylee grouch]

A call to the " lock doctor " at Cabin Creek might be a good option.

[Bigmon]

I thought about sending it to him.  I am trying to rough in a rifle "in the white" for a fella with a low budget so I am trying to fix it myself.  But on the otherhand, it needs to be absolutly safe.
If it were for me, I'd have already contacted him.
I guess if I mess it up, then I can always get it redone?
Thanks again ya'all.

[Bob Roller]

On a lot of my locks I counter bored the sear screw threads and made the screw with a stub thread and that made it hard to clinch the bridle against the sear.
Bob Roller

[Blacksmoke]

Most of the time I just make another screw with limited threads so they tighten against the lock plate without pinching the bridle against the sear. And always turn the screw shank several thou larger to reduce the play in the sear screw hole. H.T.

[Bigmon]

Sounds like a great way to fix the over tightening proble,  But I do not have any way to do that.  If I had a screw that the threads were too short, I could run a die over it until it was right.  But once too long, I just have to live with it.
I been doing it that way for 40 years.
I was able to stone that ledge or notch in the tumbler some more, and take the knife edge off the sear tip.  It will trip every time now, but very hard.
I am going to install the trigger the way it is, and see how hard it is then?
I will report back.  Again, thanks to all.

[Steeltrap]

I’ve taken a bigger screw, like a #8 or #10, that wasn’t fully threaded, chucked it in a drill press, filed it to the diameter I wanted, the threaded it with the die. It works well.

[smylee grouch]

Make sure any spring\lock bearing surfaces are properly greased\lubed.

[recurve]

If all else fails, contact Brad at cabin creek he is the lock Dr.