AmericanLongRifles Forums
General discussion => Gun Building => Topic started by: smart dog on April 06, 2021, 08:53:55 PM
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Hi,
I thought I would give you folks a tour around a fine 1785-1790s English lock made by a top London maker. H. W. Mortimer was one of the best makers in London during the last quarter of the 18th century and the beginning of the 19th century. He was unusual in that he was free of the gun makers guild but also the goldsmith's guild. He did a lot of his own decorative silver and gold work.
(https://i.ibb.co/yVTncyT/OLYMPUS-DIGITAL-CAMERA.jpg) (https://ibb.co/FnvbLwv)
(https://i.ibb.co/ByZHx0G/OLYMPUS-DIGITAL-CAMERA.jpg) (https://ibb.co/2vt0QGS)
The lock probably is from the late 1780s and features a flat beveled plate and flintcock, guttered gold lined pan, roller frizzen, and tumbler with stirrup. The decoration is simple and includes some sparse engraving and Mortimer's name engraved within a gold inlaid panel. Even if the lock was finished bright, the dark running leaf border would make the gold name plate stand out. The tumbler bridle also is extensively engraved, something that was not uncommon on higher quality guns. The lock plate and flint cock feature nice "ovolo"moldings typical of better flat-faced English locks. British makers borrowed that design from the furniture and architectural trades.
(https://i.ibb.co/6FFQX75/OLYMPUS-DIGITAL-CAMERA.jpg) (https://ibb.co/3ccKR9H)
(https://i.ibb.co/dg8Hb6Z/OLYMPUS-DIGITAL-CAMERA.jpg) (https://ibb.co/cL4sbtq)
(https://i.ibb.co/Rg2KstM/OLYMPUS-DIGITAL-CAMERA.jpg) (https://ibb.co/dfBvVX3)
Looking inside, you can see the wonderfully engraved bridle. The mainspring is itself a work of art. The long lug or tab on the upper leaf positions that leaf low relative to the bolster. That allows the lock to be mated with large barrels without the spring breaking into the barrel channel. Note that the lower leaf gracefully tapers in thickness. When the lock is brought back to full cock, the lower leaf is straight and the main bend pinched. That shows the entire spring is working rather than the main stress happening at the middle of the lower leaf as in the modern-made lock shown below.
(https://i.ibb.co/JCpxwbc/OLYMPUS-DIGITAL-CAMERA.jpg) (https://ibb.co/XV5yrdW)
(https://i.ibb.co/PGC3MW7/OLYMPUS-DIGITAL-CAMERA.jpg) (https://ibb.co/pjXGQKt)
(https://i.ibb.co/hdPGgX1/OLYMPUS-DIGITAL-CAMERA.jpg) (https://ibb.co/rpCBQbf)
(https://i.ibb.co/CskGz6h/OLYMPUS-DIGITAL-CAMERA.jpg) (https://ibb.co/XkhRbDS)
As the lock is brought to half cock, look how close the pivot on the bottom of the stirrup and within the claw of the mainspring comes to the axle of the tumbler. At full cock, it is very close giving the mechanism very strong mechanical advantage. Also note how little the spring moves upward from half cock to full. There is a bit of let off in force needed to bring it to full cock. The lock requires 6.7 lbs of force to bring it to half cock and 6 lbs of force to bring it to full. In contrast, for the modern-made lock showed previously, the force required to bring it to half cock is 9 lbs and 10.2 lbs to bring it to full. Note how robust the stirrup is on the Mortimer lock and it is pinned to the tumbler with a tiny screw rather than loosely sitting in a yoke.
The position of the sear does not change when the lock is at rest, half cock, and full cock as shown below.
(https://i.ibb.co/X3nyPkZ/OLYMPUS-DIGITAL-CAMERA.jpg) (https://ibb.co/GtZsD3v)
(https://i.ibb.co/nPszHwP/OLYMPUS-DIGITAL-CAMERA.jpg) (https://imgbb.com/)
(https://i.ibb.co/hYTbfS3/OLYMPUS-DIGITAL-CAMERA.jpg) (https://ibb.co/tL1gX9V)
That is highly desirable when you are fitting a simple trigger to the lock. You can fit it so there is no trigger rattle at any position, and no trigger creep when firing. The tumbler does not have a fly detent and doesn't need it because the gun is fitted with a simple trigger. The configuration of the notches is perfect. As you can see the lip of the half cock notch is a shorter distance from the tumble axel than the lip on the full cock notch.
(https://i.ibb.co/qMhjygz/OLYMPUS-DIGITAL-CAMERA.jpg) (https://ibb.co/PZJjmWR)
(https://i.ibb.co/2MjM2Rw/OLYMPUS-DIGITAL-CAMERA.jpg) (https://ibb.co/JpzpL8N)
That prevents the sear from slipping into the half cock notch when the gun is fired. Some modern locks have that relation reversed and rely on an overly large fly to push the sear away from the half cock notch. You often will notice excessive wear on the tip of the sear where it rides over the fly on those locks. The bridle, sear, and tumbler have friction reducing collars. However, I believe the height of those on this lock is over kill and likely a marketing gimmick more than anything else.
(https://i.ibb.co/VMfJBRd/OLYMPUS-DIGITAL-CAMERA.jpg) (https://imgbb.com/)
The frizzen has a roller bearing in its toe, a feature that became popular in the late 1770s and 1780s. Later locks usually had a roller mounted in the spring. For its size, the frizzen is thick, which I believe adds mass and enhances sparking.
(https://i.ibb.co/wsVmPbn/OLYMPUS-DIGITAL-CAMERA.jpg) (https://ibb.co/yStjZMz)
It requires 4 lbs to open it, which is about 69% of the maximum force required to pull the flintcock back to full from rest. That is a bit stiffer than I usually try to achieve on my locks but the proof is that this lock really sparks!
(https://i.ibb.co/tDpZn4y/mortimer-sparking.jpg) (https://ibb.co/7KtgBX7)
By the time this Mortimer lock was made, the styling of British sporting guns changed from what we often think of as the classic mid-18th century British gun. Combs were lower, butt stocks smaller, locks smaller, and almost always flat faced on anything but military, cheap livery and trade guns. Wrist checkering was evolving. It is a great lock and represents top of the line work by a great maker.
dave
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Thank you.
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He was also a good teacher as some of his apprentice,,s went on to be high quality and famous gun makers too. I think Manton , maybe Purdy, and Boss come to mind and probably more.
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Thanks, Dave. That lock screams quality! Best,
Ed
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I really appreciate the time and knowledge you share in posts like this, it helps dummies like me to get a better grasp on lock construction, Roland
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Hi Smylee,
Mortimer was probably a good teacher but he mainly taught his sons. John Manton was apprenticed to William Edson of Grantham. Nothing is known of Edson except he was associated with Edward Newton's gun shop in Grantham. It is possible that he was Newton's foreman and allowed to take on apprentices like Manton. The key player here is the great Edward Newton who taught Robert Wogdon and John Twigg, and probably John Manton. John Manton then went off to become John Twigg's foreman in London before setting up on his own. Joe Manton was initially apprenticed to probably William Newton in Grantham but switched to his brother, John in London. Thomas Boss learned his trade first from James Purdey and then Joe Manton. James Purdey apprenticed to W. K. Hutchinson and then went on to work for Joe Manton. He left Manton and worked for Alexander Forsythe, the inventor of practical percussion ignition for firearms. Then Purdey struck out on his own. The "academic father, grandfather, and great grandfather " in all of this is Edward Newton from the little market town of Grantham. It is also fascinating that Edward Newton, William Newton, John Twigg, Robert Wogdon, John Manton, and Joe Manton were all raised in Grantham.
dave
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I really appreciate the time and knowledge you share in posts like this, it helps dummies like me to get a better grasp on lock construction, Roland
Dave ... ditto for me too! Far55 said it better than I could. Thanks.
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Hi Dave and thank you for that info. I can't member the title now but thought that I had read that john manton had worked under Mortimer and after your post I think I remember some of those other names working under manton.
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Lock MAKING as opposed to assembly is a combination of several skill sets involving
machines,spring making involving shaping hardening and tempering and choosing and
sourcing materials.We have an advantage today that wasn't even dreamed of 250 years ago
in the sourcing of material and precision measurement with now common tool like a simple
micrometer.
The lock shown here is a marvelous example of what can be done even without the advantages
we now consider common.I made my last mechanism for a Durs Egg flintlock on the Friday before
the 2019 CLA Show In Lexington and that was it.
Bob Roller
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Hi Folks,
You are all very welcome and there will be more. I will be adding some new parts to my tutorial "Understanding British Fowlers". The additions will include complete photo essays of 3 new fowlers including the Mortimer for which the lock was made. I'll be able to describe and document changes in styles going into the 19th century. It will take me some time to complete all the additions because I won't have the barrel and mounts for the Mortimer gun until June.
dave
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I can't say anything that anyone else hasn't said but I will say your knowledge of all the intricasies of gun building amaze me. I picked up on that when we had our hour long consultation at Dixons a couple of years ago. Thank you for sharing that knowledge!
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The number and quality of today's locks is pretty impressive (interchangeable parts). The old locks were individually forged and filed by hand from iron, and the concentrated thought of the lock smiths building them. Some old locks are barely stuck together but many are virtual machines. The mortimer lock you have shown us is an excellent example of what human hands and a few tools are capable of. Rediscovering the secrets of lock geometry and construction is a wonderful adventure. A great lock to build from castings is the Probin flint lock from TRS. The casting set is a little bag of impossible looking parts that becomes a very cool lock.
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In order to make the much-vaunted one-position-sear, that full cock notch must be VERY deep. It looks that way in the photo. How would this very long let-off be countered? Or would it? The trigger pin would have to be spaced fairly far away from the sear bar ...farther than the sear bar is from the sear screw in order to "outrun" the sear lever/arm and speed that sear nose up as much as possible so that the trigger pull wouldn't take four minutes to let-off. Am I thinking correctly on the mechanics of it?
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Notice the hook in the front. These hooks were mostly inlaid into the lockplate. Looking very closely it is difficult to tell even with a microscope. Also notice how low the spring is mounted on the plate. This is important.
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Wonderful tour Dave, thanks for showing us this! Very nice lock.
Curtis
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In order to make the much-vaunted one-position-sear, that full cock notch must be VERY deep. It looks that way in the photo. How would this very long let-off be countered? Or would it? The trigger pin would have to be spaced fairly far away from the sear bar ...farther than the sear bar is from the sear screw in order to "outrun" the sear lever/arm and speed that sear nose up as much as possible so that the trigger pull wouldn't take four minutes to let-off. Am I thinking correctly on the mechanics of it?
Hi Chris,
Your physics are not theoretically off but you are over thinking it. When I build a lock I file a nice sharp but shallow full cock notch. It is always at least the depth of the thickness of the tip on the sear. Then I assemble the lock and mark where the sear ends up on the plate at full cock. Then I put the tumbler in the rest position and if the sear is pushed up, I file the underside of the tumbler until it is level with the mark on the plate. If it drops lower, I don't worry about it because it will be held up by pressure from the trigger. Then I place the tumbler at half cock. If the sear is pushed up, I deepen the half cock notch. If it drops lower, I usually let the trigger hold it up as long as the sear has enough engagement in the notch to be safe. If not, I have to start the process again by deepening the full cock notch and going from there. In practice, I almost never run into that situation. It is always the reverse, the sear is pushed up. The whole process is focused on having proper engagement at full cock that results in a crisp light trigger pull with no creep. The real balancing act, however, is then making sure the lip of the half cock notch is at or below the radius depth of the full cock notch if the lock has no fly detent.
dave
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On the locks I made the sear was not shaped until it was functional in the half and full cock positions
and the fly-detent-intercepting cam was working.
TRS has some good looking external flintlock parts but I think using the already too flimsy internal
parts as mould masters is not a good idea if the gun is to be shot a lot.There IS a reason so many of
these marvelous relics survive in nearly new or as new and that is they were NOT used or used very
little.Museums and private collections have a lot of them and probably these guns were symbols of
wealth.
Bob Roller
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Well done, look forward to the series.
Tim
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Dave, thank you for the photos and explanation of lock works. It was a small community of gunmakers and apparently they were all familiar with each others work. A question about triggers, were there any trigger springs that kept the trigger in contact with the sear that prevented a loose and floppy trigger?
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In order to make the much-vaunted one-position-sear, that full cock notch must be VERY deep. It looks that way in the photo. How would this very long let-off be countered? Or would it? The trigger pin would have to be spaced fairly far away from the sear bar ...farther than the sear bar is from the sear screw in order to "outrun" the sear lever/arm and speed that sear nose up as much as possible so that the trigger pull wouldn't take four minutes to let-off. Am I thinking correctly on the mechanics of it?
Chris,
You are absolutely correct. Having a very deep full cock notch isn't a good thing. A fly solves the problem.
Jim
Jim
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This is a very nice lock and there are a myriad of details, functional and aesthetic, that make this special. There are few commercial locks that come close to this. In making a fine lock, there are so many details to consider. 99.99% of consumers don't understand or appreciate these. Thanks for sharing, Dave.
All the best,
Jim
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Thank You Dave!
I agree with everyone else that this post is a wonderful opportunity to study and learn from. I'm sure I will be visiting this again and looking and reading about this fine lock.
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Dave, thank you for the photos and explanation of lock works. It was a small community of gunmakers and apparently they were all familiar with each others work. A question about triggers, were there any trigger springs that kept the trigger in contact with the sear that prevented a loose and floppy trigger?
Single triggers with no set capability can be lightly uploaded with a small spring and
this is standard on high end English percussion target rifles. The spring allows the
release bar to follow the sear in all positions.
Bob Roller
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Dave,
Can we get a close up of the hook in the front of the lockplate? Does it work with a pin or a screw head?
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Dave,
Can we get a close up of the hook in the front of the lockplate? Does it work with a pin or a screw head?
Sure thing Clowdis.
(https://i.ibb.co/DwTnfYw/OLYMPUS-DIGITAL-CAMERA.jpg) (https://imgbb.com/)
(https://i.ibb.co/ZJ6D3sX/OLYMPUS-DIGITAL-CAMERA.jpg) (https://ibb.co/DbD2NXW)
(https://i.ibb.co/ZJthVVW/OLYMPUS-DIGITAL-CAMERA.jpg) (https://ibb.co/26mjyyg)
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In order to make the much-vaunted one-position-sear, that full cock notch must be VERY deep. It looks that way in the photo. How would this very long let-off be countered? Or would it? The trigger pin would have to be spaced fairly far away from the sear bar ...farther than the sear bar is from the sear screw in order to "outrun" the sear lever/arm and speed that sear nose up as much as possible so that the trigger pull wouldn't take four minutes to let-off. Am I thinking correctly on the mechanics of it?
Chris,
You are absolutely correct. Having a very deep full cock notch isn't a good thing. A fly solves the problem.
Jim
Jim
That's the only two ways I can see to do it. Either use a fly to bump the sear up (actually, down) over the half cock hook, or make the full cock notch and the half cock hook about the same radius away from center... and then you have to make the full cock notch at least as deep as the thickness of the sear nose, PLUS the thickness of the half cock hook to get the sear to sit in the same position at half and full. I'm just having a hard time understanding how this ultra deep notch would be made to work satisfactorily. That makes for a LOOOONG pull, which, I suppose could be compensated for by a really long, far forward trigger spacing, to attempt to speed up the sear nose. I'm not sure how successful that might really be. Maybe it's just a shotgun thing. Follow through, and all that. Just keep pulling the trigger until it goes off. I'm definitely not a shotgun shooter.
???
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Hi Chris,
What are you talking about? There is no "ultra deep" full cock notch on this lock. The lip is just a little further from the tumbler spindle than the lip of the half cock notch. It is not a "deep notch". The trigger pull is light and crisp. I produce locks without flies that have light (1.5 lbs) and crisp trigger pulls all the time. You just have to have experience with that design and know what you are doing. Actually having direct experience with these kinds of locks helps to understand them.
dave
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Forgive me, I'm apparently missing something entirely.
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Wow what a great lock. I wish we could get locks this nice today but like Jim said most people don't understand a great lock. Most people refuse to pay for that kind of work because of the lack of understanding. I have to admit I was in that crowd at one time. Thanks for showing all of us the lock. I do have one question though. Does the lock "jump" a bit when fired or does it lay smooth in your hand. Not sure if that question makes sense or not.
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Wow what a great lock. I wish we could get locks this nice today but like Jim said most people don't understand a great lock. Most people refuse to pay for that kind of work because of the lack of understanding. I have to admit I was in that crowd at one time. Thanks for showing all of us the lock. I do have one question though. Does the lock "jump" a bit when fired or does it lay smooth in your hand. Not sure if that question makes sense or not.
You also have to realize that this was definitely NOT your average common-or-garden-variety gun lock of 230 years ago. The vast majority of locks were nowhere near as finely fitted or finished. This was a lock made for a gun made for an English gentleman, who had money to burn (or was highly in debt, but still felt the need to keep up appearances...). ;)
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Dave, thank you for the photos and explanation of lock works. It was a small community of gunmakers and apparently they were all familiar with each others work. A question about triggers, were there any trigger springs that kept the trigger in contact with the sear that prevented a loose and floppy trigger?
Single triggers with no set capability can be lightly uploaded with a small spring and
this is standard on high end English percussion target rifles. The spring allows the
release bar to follow the sear in all positions.
Bob Roller
Bob, thank you, that is nice to know. I appreciate your sharing your insights, especially locks and triggers.
Cheers Richard
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Smart dog, I'm going to ask a question but please dont execute me for the comparison 🤣 but the outside of the Mortimer is very similar to the l&r Durrs Egg (dont shoot) so was he influential in inspiring that particular lock maker?
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Hi Scott,
No. It was a pretty commonly used style. Durs Egg emigrated from Switzerland or France to London as a fully trained gunsmith in 1772. He came to work for John Twigg stayed with Twigg until he set up on his own in 1776. In fact, he took over Twigg's premises in the Strand when Twigg moved his business to Piccadilly. You can make an L&R Durs Egg lock into something approaching this quality but it takes some working it over.
dave
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The last two locks I made were the Durs Egg and they both had better looking mechannisms
and closer fit parts.It takes experience to do this and that is one thing I have and now hand
skills are being replaced by CNC and that is the order of progression and I am glad to see it.
Bob Roller
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Dave,
Chris is right. I don't think you are understanding things correctly.
Here is what you said in your original post:
The position of the sear does not change when the lock is at rest, half cock, and full cock as shown below.
That is highly desirable when you are fitting a simple trigger to the lock. You can fit it so there is no trigger rattle at any position, and no trigger creep when firing. The tumbler does not have a fly detent and doesn't need it because the gun is fitted with a simple trigger. The configuration of the notches is perfect. As you can see the lip of the half cock notch is a shorter distance from the tumble axel than the lip on the full cock notch.
The key phrase is "the lip of the half cock notch is a shorter distance from the tumbler axel than the lip on the full cock notch"
With a one position sear, it would be required that the full cock notch be extremely deep for this statement to be true. No debate, simple geometry.
Jim
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The lock was probably made by a lock maker.
This should take you to scans of the "On Locks" chapter of W. Greener's "The Gun" 1835
This book is available as a PDF on the WWW. Once you sort through the versions of "The Gun and It's Development" by his son W. W. Greener
https://www.facebook.com/media/set/?vanity=100000127103372&set=a.4561092173904974
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Dave,
Not had much forum time for a while.
Thank you for this thread.
Thank you also for your detailed study of the lock. I must say, you See very well!
I also greatly enjoyed your writing of some of the English makers, including the progeny if you will, of Edward Newton. He was a master craftsman even if a Provincial maker. Elston of Doncaster was another.
Thank you again for this detailed look!
Best,
Richard.
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I think Dphariss is probably correct. This lock and most likely all the locks for the major gun producers in England were made by professional lock makers. This was an industry in England in the 18th Century and also most likely several people were involved in the manufacturer of one lock. Seldom was a lock ever made by one man. Different records testify that about 22 people were involved in the making of a gun in England. The Manton factory took up about a city block and was a 2 story building. I read someplace that he had about 250 employees.
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Hi and thanks for looking and commenting, everyone!
I kind of put this thread on hold for a bit because I had to do other things and I wanted to add some photos and measurements of original locks to address the comments above by Jim Kibler and Stophel. I will get that done soon. Don, Richard, and Jerry are absolutely correct about multiple tradesmen involved. Mortimer had a lock maker. Some had them made "in house" and others subcontracted out. My purpose was not to highlight the manufacturing process but to point out the features that make the lock so good regardless of who made it. The Mortimer lock has a stirrup tumbler but a measure of that mechanical advantage and good geometry can be duplicated with a simple hook and toe tumbler. The secret is to design the mainspring so the hook rides the full length of the toe on the tumbler ending up at full cock right against the axis of the tumbler. If you get it just right, the tumbler toe lifts the spring a little as you bring it to full cock but it also pivots around the end of the hook. The result is a little let off of pressure making it easier to adjust a light trigger pull with a simple trigger.
dave
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Dave,
If you are going to provide more info on this lock, I would be interested in the thickness of the lock plate and the thickness of the flint cock at the pivot hole. Also the thickness of the tumbler. There is lots of data on general lock configuration, not so much on material thickness and height of the bolster. Most of my locks tend to be a little thick ( .160" - .175 ") as I am looking for a firm thread base on wrought iron plates.
R/S Clint
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Hi Clint,
I will do more than that. I'll post those dimensions for several English locks from different periods.
dave
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The profile of this lock is nearly identical to the Nock/Bailes I made for the shop
of Helmut Mohr in Germany.I owned these moulds for the plate,cock and frizzen
and gave them to Les Barber and Larry Zornes to use for any project they might be
compatible with.It is also close to the current L&R small Manton.The REAL lock is
the mechanism on the back of the plate and the "engine"is a mainspring preloaded
to give abrupt acceleration to the cock when the sear releases it.My lock making days are
over and other than Jim Kibler is anyone making a lock with the "anti friction swivel"
and a powerful mainspring?A stiff spring is frequently just that,stiff.Hold the sear up
and pull the cock back and forth and there should be an "oily"feel to it with no noticeable
drag from the mechanism.
Bob Roller
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Bob,
You are dead right on the "Oily" feel of a good lock. No friction at all is felt.
I believe it was Col. Peter Hawker, who first used the term, "oily".
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Hi Guys,
I am so sorry this took so long but I was incredibly busy with finishing the Edward Marshall rifle but also reviewing a very large science book for the author. I am supposed to be retired. I also wanted to add a bunch of data to this thread that may be useful to some who obsess about locks like me. To others it may be over the top but there it is anyway. In this post I just want to add info for Clint and respond to Jim Kibler's previous response. Then in a second post I am going to add a bunch of new pictures and a plethora of measurements of the tumblers, sears, bridles, and mainsprings from 2 fine English locks.
Clint, here are the measurements you asked for on the Mortimer lock. The general thickness of the lock plate is 0.123". The thickness of the plate with bolster measured directly behind the pan is 0.265". The thickness of the flintcock at the tumbler screw hole is 0.125" I will measure more lock plates and flintcocks for you a little later.
With respect to Jim's comment, our disagreement is not about geometry because I understand this stuff as well as he does. Where we are talking past each other and with Stophel is what constitutes a full cock notch that is too deep but that keeps the sear in the same vertical position at half and full cock. So here are some data from 2 fine English locks. On the Mortimer lock the distance from the tumbler spindle to the lip of the half cock notch is 0.395". The same measurement for the full cock notch is 0.410". The depth of the full cock notch is 0.037". I measured another lock by Field, which is a very late flintlock era lock. The same measurements are 0.473", 0.484", and 0.06"; respectively. The depths of both full cock notches are deeper than the thickness of the tooth on the sear. I cannot measure the Mortimer right now because I don't have the triggers. They are being browned with the other hardware and barrel by a gunsmith out west. I'll have them soon but I do have the complete Field fowler and the trigger pull is crisp, no creep at all, and measures 2.8 lbs. The sear spring is very stout so I could reduce it and create a trigger pull around 2 lbs as I have on guns with locks I've built that did not have flies and had well behaved sears with no creep and crisp let off. My current favorite rifle is one of those. However, I would not go much below that because it would risk the sear engaging the halfcock notch when fired, which is why fly detents were added. My point here is that the "deep" full cock notch that Stophel and Jim assumed would be bad for performance does not have to be unless you want a trigger that performs like a set trigger. Then you need a fly.
dave