Making a Tumbler

[David R. Pennington]

Making a tumbler. Pictured is the parent stock and a piece I cut off. Old octagon tool steel stock. It was way too hard to machine so I managed to whittle off a couple chunks and brought them up to a good red heat in the forge and soaked a little then left them buried in the forge fire overnight and half a day. Now it machines like butter.
Turned out a rough blank. I have never made a tumbler from scratch so I'm trying to figure this out as I go along.
I found this set of lock castings and they look right for the next rifle I want to build only there is no tumbler. Basically there was a plate, cock, top jaw, mainspring and frizzen spring and frizzen. I must make a tumbler, bridle, stirrup and sear and spring, plus screws of course.
I want to think this through. I guess next step would be to drill and ream plate for tumbler shaft, then try and figure out mainspring location and cut tumbler arm in relation? How would you lock maker proceed?

[Acer Saccharum]

This is one of those things where you can cut off too much too soon. It's nice to have other locks to compare the innards with.

Maybe Bob Roller or James Wilson Everett can shed some light on the subject.

....an old post of mine, where I go on and on about tumbler making. http://americanlongrifles.org/forum/index.php?topic=13919.msg131057#msg131057


Try the search function out, see what you get. I thought I posted something more complete, but no cigar, not yet.

[Acer Saccharum]

David, this won't really help you, but it might help someone sometime. Use the concept for lock plate duplicating, or lock inlets, or whatever you turn your little minds to. Keep you off the street for a few hours.


For this, you need a lathe and a mill.

The concept of a duplicator. the mill spindle is on the left, and a trace arm is connected by a bar on the right.



In practice, tracing carefully around the original tumbler



Image of the near complete tumbler, workpiece on the left, original on the right.



Turning the shank after the milling is done.

[John A. Stein]

If the works of Pryor Mountain Bill are still available I believe he had a booklet on making a lock. The information on design and layout would be a big help. John

[WadePatton]

David, this won't really help you, but it might help someone sometime...

I love/hate that you did that.

thanks Tom!

[David R. Pennington]

I don't have a mill, but have a little Sherline lathe. I have taken apart my small L&R Manton and it looks like the tumbler for it would be close. I have to remember how the mainspring rests higher on the lock plate with a stirrup type spring. The cock already has the square hole cast in so I need to get the timing figured out. Good learning experience.

[jerrywh]

 From my experience everything is in relation to the position of the hammer. I first install the hammer and then figure the position of the other features. When making the hammer square don't forget the square for the hammer is tapered. If you don't put a tapper on the square the hammer will never stay tight.

[Acer Saccharum]

Jerry, I recall someone here made a square drift punch, with tapered sides. Lube it with some lithium or moly grease, and hammer it in the square hole of the hammer to swage it square and tapered.

[Bob Roller]

I have made and still use a tapered swage to fit a percussion hammer but can't recall if I ever posted about it on this forum. 2 degrees on a side lor 4 included.

Bob Roller

[omark]

Now that is a very good idea.    Mark

[shortbarrel]

Bob I made a square broach many years ago. If I remember remember right It was a bitch to make, but have  used it many times on hammers. Use it on a arbor press or heavy drill press. have you ever made one?

[jerrywh]

 I have a half dozen square broaches and one or two of them I hand made about 50 years ago. It is best to press them in with a vise and socket. But it is still hard to get the hole in the exact position. That is why I used to install the hammer first.

[Acer Saccharum]

I agree with Jerry about the hammer first. With the hammer stall down(the shoulder that stops it on the plate edge), one can then fit the bridle. The tumbler should not rely upon the bridle to stop it, this is the job of the hammer stall.

[Acer Saccharum]

I don't know enough about lock making to tell you the proper sequence of fitting components and design.

[omark]

Acer, I understood the stall and the tumbler should hit their respective stops at the same time. Is this wrong?        Mark

[Mark Elliott]

At least one of those broaches is on my to do list.   Without one, I have a terrible time getting cocks/hammers in the right position just using a needle file.

[David R. Pennington]

How about some explanation on how the broach is used on fitting up cocks and tumblers?

[Bob Roller]

 The cock or hammer should be fit to the disc if you are making a lock from scratch like I do.
  Right now I am making five schuetzen locks to deliver to a German customer in Friendship in
  a couple of weeks.I am using the L&R plates and the Davis hammer as sold for Alex Henry
  caplocks that have the square hole cast into them.
  On hammers without a square hole,I drill a hole in them and file it to rough square and then
  press the tapered swage into it with a 5" vise to match the taper established by a tapered 3 flute end mill.
  The Davis hammers and the L&R's that I use have a square cast into them so I mill the tumbler shank to
  come close to that pre established hole and carefully file the hole to size.I use a very narrow pillar file I
buy at a local industrial supply shop. I've used these methods for years with no apparent trouble.
The tumblers are made to the configuration shown in a picture and ALL of mine start out as a 1.250 diameter x.234 thickx.312 shank.140 bridle bearing disc made of 1144 "Stressproof". It machines like 12L14 and hardens like 0-1 and seems to be trouble free with only one reported breakage in the last 30+years and that was an altered tumbler in Europe.

Bob Roller

[Bob Roller]

Mark,
A needle file is a finishing file. I have a wide assortment of them and wouldn't try to use one as an all purpose tool on fitting a hammer by filing a round hole out. Read my last post on this subject.Most industrial supply shops will send you a catalog and I prefer them to this "on line"thing and their catalogs are free upon request.
There are also companies that specialize in all kinds of odd files as well.Those will have to be on line searches but they are "out there". Let me know how you do with this.

Bob Roller

[Acer Saccharum]

Acer, I understood the stall and the tumbler should hit their respective stops at the same time. Is this wrong?        Mark

Is it wrong?

I don't know, to tell you the truth.

Let me think about it in these terms: I just go by my own sense about machine design, what takes the strain, and what to protect from strain. I would not want the bridle or bridle screws to suffer ANY lateral movement. This movement will affect the sear, trigger pull and the delicate nature of the internals. You might think the hammer stall will prevent that, but the stall will eventually peen its way into the plate a little, causing strain on the bridle, its screws, etc. This is why I wouldn't have the tumbler stop on the bridle simultaneous with the hammer stall.

[JTR]

I have a very nice condition original British Baker flintlock, and the hammer and the tumbler hit the stops simultaneously.

Makes sense, as two stops hitting simultaneously will result in less wear to hammer and tumbler. 

John 

[Acer Saccharum]

Good quality old locks had careful fitting and plate and cock are casehardened. This will allow a long service life. If your plate and cock are not hardened, I'd make the cock stall be my first line of defense.

[Dr. Tim-Boone]

Small Siler Hugh Toenjes made for me has an adjustable stop screwed into the tumbler so that it is easy to time so that the hammer hits both stops at the same time. Its part of the overall balancing he does. 

[davec2]

Bob Roller,

How do you heat teat 1144?  I'd like to know your method.

Dave C

[Bob Roller]

It's a simple thing to work with. Heat it bright orange and quench in light oil.I use hydraulic jack oil.
Use a magnet and get it out of the oil and wipe it off. Polish with 320 Aluminum oxide cloth on all
surfaces. Heat carefully until a light straw color appears and drop it back into the oil.Get it out when it cools off
and it's ready.I have used this method for over 40 years and to my knowledge,no unaltered tumbler has broken.
One that was altered,I think perhaps some kind of a nitride bath and it was on a lock that was in Germany.
The arm broke that supports the link to the mainspring and it was hard as glass.The tumbler is the only piece I make from 1144.The sear and fly are 0-1,screws are 12L14. This is my version of the KISS principle.

Bob Roller