Lockmaking-the fly

[Scota4570]

I am making progress on my Kibler SMR cap conversion lock.  I have a new found respect for anyone who can make a quality lock from scratch.  Doing my first one, making the templates, as I go is quite tedious.  The first 100 are the hardest, right?

I made the bridle more like Bob Roller than Jim Kibler.  I regret that now, I think. 

The fly will peek out the side more than I want if I make it as shown below. About half will be captured by the bridle.   

 Hidden fly option, If I put it on the back side of the tumber, like Jim, may be an issue.  I made my tumbler 5/16" instead of the 0.292" shaft Jim uses.  If the fly is 0.010 shorter than the Kibler fly will it matter?

Exposed fly option,  How much of the fly needs to be captured by the bridle? 


I like the idea of putting it on the outside to make trouble shooting easier. 

Thoughts?? 

[D. Taylor Sapergia]

As long as the bridle keeps the fly in its little hole, it doesn't matter.  The fly must also be able to move forward and backward without binding but that is very easy to accomplish.  Drill the hole for the tit on the fly as close to the tumbler axle as you dare...in other words, make it as long as possible.  The tit on the fly needs to be no more than 1/16" in diameter.  I cut mine after roughing out with files, with a hollow end mill (homemade).

[Bob Roller]

Move the hole for the pin to the left of that small support post and reangle and widen the inverted "V".There is nothing wrong with a pin and the fly having a hole but I used the system Taylor described and the miniature hollow mill.IF the half and full cock positions are in place and finished then install the fly and carefully file it until a good engagement is achieved at half cock and then move the fly forward and file the approach angle so the sear goes over the half cock and then harden and temper the fly and sear.Take your time.MAKING a lock is not easy and after doing it for a long time I got tired and stopped in 2019.The very LAST lock was a J&S as seen on the Peterson and the mechanism was like those seen on many old caplocks,No fancy work,full cock only,one screw in the top of the bridle plus a 3/32 pin and temper color on both springs.Get to the point where a usable lock can be made and then figure out ways to make them good looking or even fancy like the
lock filers of England in the mid 19th century.THEY set standards that CAN be duplicated today.
Bob Roller

[Scota4570]

I'll have to look for a tiny shell mill next time I visit the machine tool supply store.  I have made the integral pin on the lathe.  I then part off the flat part of the fly.  I have no suitable good steel right now.  My 1144 is 1 1/8" so making a fly out of it is a bit wasteful. 

[Jim Kibler]

You can pretty easily make a hollow cutter out of a piece of O1 or similar material.  Just turn it on a lathe and file the teeth.  Of course harden and temper afterwards. Cut slowly with oil and you should be good.

[Goo]

In my experience I have had to make a number of replacement fly`s  you gain a lot of respect for that small part of the lock. If you put them in backwards the sear catches at half cock. If you don`t get the angles right on the business end of the fly the lock catches at half cock. if you don`t harden them the tip wears off and the lock catches at half cock. Too big, too small too tight, too loose, it is  goldilocks and the three flys.     kudos to you for trying! keep it up when it works you will be pleased with your accomplishment. 

[Bob Roller]

My hollow mill for the one piece fly is made of 3/16" (.1875)oil hardening drill rod and I used i.250 1144 for tumblers.
Drill a 1/16" hole and the ream with a #44 reamer(.078) and be sure to use a good oil or threading fluid on the reamer
and then file the teeth and remember the direction of rotation.A similar tool can be made for the link that captures the mainspring.
Benchcrafting a lock is work and combines machinist skills plus beneficial materials and hand skills with files.There IS a reason
English lock makers were called lock FILERS and the better the quality of the small files then the better the job may be.Filing guides
for the areas of the bridle that house the screws can be made from drill rod.These guides work like a nut and bolt.The bridle can be
the focal point and here's my way of doing them. I have made screw hole locating fixtures from flat 0-1 and drilled holes with a #44
drill to locate the holes in both the bridle and the lock plate.The bridles are 1018 or low carbon flat ground either 5/16x1 and 1/4 or
3/8x1 and 1/4.The 5/16 is /was used for most cap locks and flintlocks I made over a long period and the 3/8 started in 1987 when I
made the first "4 pin"using a fine original Stanton lock borrowed from Lynton McKenzie.All my screws were made from 5/32"drill rod and then the same diameter 12L14.After milling a strip of the 1018 to accommodate the .230-.234 thickness of the tumbler then the holes
are located using the fixture mentioned earlier and a #44 drill is again used to drill thru the 1018.Then a 5/32" counter bore is used that
has a .078 pilot is used to bore the seat for the screw head to a depth of 3/32".The #44 holes are bored out to .110-.112 to accommodate the 4x40 or 4x48 screws that a found in these high end locks.The hole for the small tumbler bearing is drilled with a .135 drill and reamed to
.1405 and be sure to use a threading fluid on the screw head counter bores and the tumbler.NOW,the detailing around the screws will make or break the appearence of the mechanism so using a piece of drill rod,(.204)a filing guide is made and I make 4 of them for the fancy English bridles.Turn it to .155 to the diameter of the screw head and THEN to .108 and thread it 4x40 or 4x48.The length should be 5/8
and the head should be about 1/4" long for a "bolt" 7/8" long.the "nut"is also .204 and threaded internally to easily turn on the "bolt"and the end that goes against the bridle should be tapered to insure centering.HARDEN the "bolt" heads and the FULL length of the nuts".I used water hardening drill rod.For common 3 screw bridles (Hawken) and others a stub length version can be used for the area of the sear screw.
Insert the "bolts thru the bridle and install the nuts to only "snug"and now you have filing guides that will allow a good looking bridle to be made.This all seems like a lot of work and if your shop has no machines to use then maybe you know someone who does."Flys" are made from 7/32x1/2 0-1 and a strip can be milled with a narrow full width strip and narrow thickness established.
ENUF for now.
Bob Roller

[kutter]

Couldn't you make the fly longer yet and pivot the top portion around the tumbler axle.

That would make a stronger part, an easier to make part with no tiny peg for the pivot leg.

The cut out for it to sit down into the tumbler  would be a circular plunge cut around the tunbler axle.  Then the necessary angled depth cuts out to the circumferance of the tumbler to allow for it's proper swing.

The bridle has much more area covering the fly this way to hold it in position.

Stevens used something like this on some of their Single Shot DST mechanisms.

[Scota4570]

You can pretty easily make a hollow cutter out of a piece of O1 or similar material.  Just turn it on a lathe and file the teeth.  Of course harden and temper afterwards. Cut slowly with oil and you should be good.

That worked out well.  Now that I have to cutter made it will go fast in the future.  I found some Graph-Mo.  Neat stuff, it machines nice.  Thanks for the suggestion.

Scot

[flatsguide]

Thanks for that informative write up regarding material and file guides...good stuff indeed.
Cheers Richard

[Bsharp]

Don't 'forget' to write on it what it is for!

[Bob Roller]

Don't 'forget' to write on it what it is for!

Material I used for locks and triggers"
1144 "Stressproof"for tumblers
0-1 oil hardening "Flat ground"or gauge stock for sears and "flys"
12L14 for screws.
1018 for lock plates (percussion)and bridles for all locks and trigger bars as well as triggers.Triggers are case hardened**.
Flintlocks were made from proprietary external castings I bought from Chambers and L&R with frizzen and spring installed
and then the Shoults Ketland,Russ Hamm Maslin and percussion hammers from suppliers that owned the production facilities
such as International Arms,now long gone and owner deceased and then Jerry Devaudreuil in Wooster Ohio until he passed
away.I have little confidence in foundries and had a lot of requests to remake locks with cast mechanisms,especially mainsprings
but had more than enough to do to avoid my own mistakes.As I have said so many times.the LOCK is behind the plate and wanted
the buyer/owner to have no trouble with mine.I'll soon be 87 and other than a trigger once in a while,I am done.Lower back spasms
and prostate have lowered the landing gear and the time to lower the flaps and pull the throttle back has finally arrived.
**SOME FEW triggers were made from 0-1 but not many.
There it is,nothing odd or exotic but it worked for me.
Bob Roller
PS:
I forgot the springs,main and sear springs were 1075 and most frizzen springs came with the external parts and I assumed they were cast.