Lock tuning question Jaeger SUCCESS

[foresterdj]

Working on a couple jaegers this winter (overreaching my skill level to be sure.). Some issues on lock functioning, here is background.

When lock was apart for inletting, I smoothed/honed the edges of springs, inside lock face and other areas where parts might rub to 400 grit, in some cases 600 grit.
Made sure designed bearing surfaces/faces were smoothed honed to 600 grit.
applied light gun oil to moving parts when re-assembled.
did tests both bevel up and bevel down.
Flint is English nominal 7/8 X 1, actually about 0.85 X 1.1"
I used 2 pieces of leather to set flint back as much as it would go, to contact with the screw.

In both orientations, when fired from the full cock position, the flint will stop near bottom of frizen, with the frizen never flipping open. Here are some pictures.
Bevel up test:


Here showing the flint position to pan with cock fully down, looks good to me.
Here at half cock.
and at full cock






Here when fired, and stuck before clearing frizen.



Same result with bevel down, I will just show the fired result.




Some observations, the bevel up would contact the frizen about 1/3 of the way up from bottom, the bevel down contacts frizzen way up 3/4 +. Bevel up, if frizen would trip open, would place frizen edge at near pan center, bevel down puts flint edge past pan when down, that is, if frizen would open and hammer would actually go all the way down. Also, with bevel down, flint contact seems to be close to 90 degree through most of the throw.

I sent a question on this to the manufacturer, but thought I would seek thoughts from the many builders here.

What should I look at next, to try and get the lock(s) functioning correctly?

[Bob Gerard]

Did it work before you took it apart?
I’m no lock maker but from what I have read is that perhaps 1) the feather spring may be too stiff or, 2) the sole toe of the frizzen may be the culprit and may be worked on to enable the frizzen to spring completely open. It might need to be rounded or even a little bit removed.
This will be good to follow.

[TDM]

Good points from Bob on your springs. Check the frizzen movement by hand to insure smooth, freedom of movement. But my main suggestion is moving the flint forward in the jaws. If you can, move it within a 1/10" of the frizzen unless this causes the flint to strike your pan.

[smylee grouch]

Is it possible that flint strike is too square on frizzen? Would flint strike at more of downward angle help open frizen?   

[Bob Gerard]

The frizzen should "snap open" at some point. Again, my guess is the frizzen soletoe, but personally I would wait to get other ideas before I started to take a small file to the metal. But rounding and polishing cant hurt I think. Then put some grease (not oil) on the contact point of frizzen sole and spring and see if it helps a little.
I dont think the flint angle or bevel orientation would matter since many locks with just a rounded, worn flint will pop that frizzen open.
Good luck- you'll get it.

[smylee grouch]

I'm thinking the flint should scrape all the way down and slice minute shavings into pan. Too direct a hit gouged the frizzen, wasting frizzen face and not directing the first sparks where you want them. 

[Darkhorse]

Even with the springs out of balance with the lock the frizzen should still snap open. It looks to me as if the flint is too far away from the frizzen face. I suggest placing a toothpick or 2 behind the flint to test the theory. At half cock I want mine just far enough away that the flint and frizzen cannot accidentaly touch each other.

[Jim Kibler]

Hard to be sure without it in hand, but probably a weak mainspring

[EC121]

The frizzen should snap open at about the same time the flint hits the bottom of the face.  30-45deg. when pushed open slowly.  If not you can stone a slight bevel on the back of the toe to make it snap over.  Then polish the surfaces to a mirror finish, and grease the spring/toe contact.  I haven't seen a lock yet that didn't benefit from a good contact point polishing.  Or at least it made me feel better.    I don't oil my locks.  Oil runs into the wood.  I use a toothpick to apply grease.  I can't see any in your pics.  After that you can move the flint out to about 1/8" or so from the frizzen.

[Blacksmoke]

foresterd:  There are several observations and several suggestions.  First that balance between cock tension ( full forward )
and frizzen ( fully closed ).  The amount of poundage to pull the cock off of  full forward should be twice that of pulling the frizzen off of full closed.  This is a standard formula for correct lock geometry and function.  Also at the point of the flint getting to the bottom of the frizzen face the frizzen should snap forward. It could be that the cam on the toe of the frizzen needs to have some polishing and adjustment where it meets the feather spring. Using your engineering skills decide what needs to be modified to accommodate the snap forward.  Some frizzen cams need to have a little metal relieved forward and some to the rear.  As to measuring cock tension use a spring operated fish scale to find the LBS. of both frizzen and cock. Also the cock tension should be the strongest fully forward and decrease as you pull to full bent position. Or full cock position.
Most lock makers fail to design this geometry into their configuration. One other observation I noticed with your photos. The cutting edge of the flint should be no more than 1/16"- 1/8" away from the frizzen face.  I hope this helps and don't be afraid to ask for more help if needed.  Hugh Toenjes         P.S.  I do not use grease to lube my locks. Grease tends to slow the mechanism down.  I use a small amount of synthetic oil mixed with graphite but accent on small amount.

[Pukka Bundook]

Are you sure the frizzen is not rebounding back into the flint, Forester?

It can happen and happens awful fast!

[okieboy]

 I agree with Darkhorse that the flint is too far back. Instead of adjusting to the pan, adjusst to the closed frizzen with the lock at halfcock; the flint suould almost, but not quite touch the frizzen. This is the easiest approach to try.

[Adrie luke]

You can make the main spring stronger for testing with a plate

[Dennis Glazener]

Copy the URL of the video then paste it in your post
 Then others can click on the URL to view the video.
Dennis

Filmed video, no rebound that I can see. I am guessing a video could be posted elsewhere and linked here, but I do not know how to do that.

[alacran]

I have this same lock on one of My Jaegers.

First let me say that I never had the problem you describe with your lock. I would say that the frizzen spring may be your problem.
Simple way to figure this out is to remove the spring and see if the frizzen snaps open.
I had the same problem on a large Siler.  I polished the frizzen spring and heated it to a blue and tried it took me two tries to weaken the spring so that the frizzen would snap open.
As far as getting a flint within a 1/16 th. or just touching is going to be difficult unless you find some extra long 7/8th flints. You will be lucky to get the flints within a 1/4. The flint will stike near the top of the frizzen and scrape all the way dow.
This is also the case with Chamber's Jaeger lock.
I would try the least invasive cures first.

[bluenoser]

The amount of poundage to pull the cock off of  full forward should be twice that of pulling the frizzen off of full closed.  This is a standard formula for correct lock geometry and function.

Thanks for that valuable piece of information.  It could help me sort out a troublesome large Siler that has spent the last few years in a drawer.  As foresterdj has mentioned, one needs to know where on the cock and frizzen to measure the pull weight.  Would it be measured between the jaws on the cock and where on the frizzen would one take a measurement?

[smylee grouch]

I have never measured that poundage but I'm thinking hook onto where ever you can as far up as you can. This might be easy on the cock but finding a way to attach that spring scale to the top of the frizzen might be challenging. Thoughts and ideas welcome.

[smylee grouch]

Interesting and thanks for taking the effort to do this. It looks so far that the poundage is ABOUT half of cock weight for the frizzen weight as stated before.

[bluenoser]

That is a great explanation and the results appear to speak for themselves.  It would not have occurred to me to use that logical approach to find the test point on the frizzen.  My thinking was along the line of equal distance from the pivot points.  Thanks for posting.

[Bob Roller]

Check the pan arm (bridle) and see if there is a drag there.My knowledge of cast main springs is zero and I used to get requests to replace them but never got involved with that Idea. I am also wondering about the hole for the tumbler in the plate,Looks a bit too far back to me and that would cause a low strike from the
flint or maybe the "cock"is too short which can create the same condition.I have seen a good many locks that have been assembled by people who have no real idea what it is they are putting together.Polish the ramp on the tumbler where the mainspring slides AND the area of full contact on the spring and a speck of STP or other "SuperSlick" on the ramp.

Bob Roller

[Blacksmoke]

It sounds like your frizzen weight is about right but the cock weights are way off.  The poundage should decease dramatically as you get to full cock position.  This for two reasons first it lessons the pressure on the sear nose in the full cock notch which in turn lessons the trigger pull # and as the cock travels toward the frizzen it will gather momentum creating more sparks and be able to push the frizzen fully forward.  This is a common problem with modern lock makers.  They do not make the hook of the main spring long enough to ride up on the shoe of the tumbler and get as close as possible to tumbler axel. The closer the hook gets to the tumbler axel the less poundage on the cock at full cock. 3#-5#at the most.
 Check an old original well made German or English lock and you will see this geometry in play. it is actually a lesson in physics 101.  Now having said all of this - yes there is a solution which I have done on many contemporary locks . You can reposition the anchor pin of the main spring closer to the tumbler which will allow the hook to ride up the tumbler shoe like it should. Sometimes only 1/6" will make all the difference. Then all you have to do is fill in the old anchor hole with a soft rivet and you are all good to go. I hope this all makes sense.
  Hugh Toenjes

[Darkhorse]

My locks are well polished at points where metal contacts metal and fishing reel grease is applied with a toothpice to those points. My tumbler is oiled, again with a toothpick dipped in oil and a applied just where I want it. The locks are smooth and fast. But there was one lock that jarred me and the rifle everytime it was shot. It was bad enough to really spread the groups out. To correct this my solution was to thin the frizzen spring until the jarring went away. This occured between 4 and 5 pounds of pressure, measured with a trigger pull gauge hooked over the top of the frizzen. Now my frizzens open between 3&.750 and 4.0 pounds of pressure. No more jarring.
I would think your frizzen should open with 4 pounds of pressure measured this way. If not check for binding of the frizzen screw or contact of the side of the frizzen with the barrel. Or there could be something out of spec. with the hammer.
I find measuring this way is a quick way of testing the spring  poundage against a known value.

[rich pierce]

Best analysis I’ve seen. I’d be getting a replacement lock. If I HAD to make this one work I think the cock should be a tiny bit taller and lower jaw angled down more. If simply bent down after straightening, flint strike would be lower on the frizzen than I would like. But obviously other locks of this exact design work, confounding the idea there’s design problem of large proportions.

[Blacksmoke]

Interesting thread so far.  Nice observations and good photography also a good grasp of the computer.!  Anyway right off the bat I add this comment:  Every contemporary lock right out of the box that I have ever seen has to be" tuned"! Yes even Kibler ( sorry Jim ) I have worked with many, many different locks they all need adjustment on some level!!  It is hard to correct this particular problem from pictures and notations.  However if all of the suggestions  were followed this lock should work!  The nubbin is called a "cam" and it works on a "over center" principle.  I have had to reshape those before as well. Wish I was there and had this lock in my hands . I have had locks sent to me for diagnosing similar problems only cost to the client was the postage. If it is an easy and short fix - also no cost to the client. Just saying.   Hugh Toenjes

[Bob Gerard]

Again, I am no expert, but looking at that frizzen spring- the end really ramps up! All the ones I see have a flatter line to them. It looks like the toe gets no relief from the drag it’s getting from the spring which would enable it springing up due to less pressure on it