lock function.

[Jotto626]

What is the function of the fly on the tumbler?

 

[Black Hand]

Keeps the cock from hanging in the half-cock notch when fired. Some locks don't have a fly...

 

[Grenadier1758]

The fly prevents the sear from entering into the half cock notch when the hammer is falling from the full cock. A fly is necessary with set triggers. A single trigger keeps the sear away from the tumbler and the half cock notch.

 

[Zonie]

Expanding on Black Hand's explanation, guns using a simple trigger usually doesn't need a lock with a fly in the tumbler.

When the lock is released by a simple trigger the continuing pull of the shooters finger keeps the nose of the sear that held the tumbler at full cock, away from the half cock notch as the hammer is falling.

If the gun has a "set trigger", things are different.

In case your new to locks, the sear is the thing the trigger pushes against to release the lock and let it fire the gun.
The sear holds the tumbler in position by positioning its hardened end into the half or full cock notch on the tumbler.
When the sear is released, it moves the end (nose) out of the notch.

Getting back to the set trigger, when the set trigger is released a heavy spring causes the (usually) rear trigger blade to snap upward and whack the sear's arm, knocking its nose out of the full cock notch on the tumbler.
Almost instantly, the set triggers blade bounces off of the sear arm.
The sear spring then rapidly pushes the sear nose back against the now rotating body of the tumbler.

If this happens quick enough, as it almost always does, the nose of the sear is set to pop into the tumblers half cock notch as it rapidly approaches.

If there is no fly in the tumbler, the nose of the sear will enter the half-cock notch and instantly stop the hammer from falling. (This can often result in a broken sear or half cock notch.)

If there is a fly in the tumbler, the body of the fly will block off the half cock notch so the sear can't enter it.
Instead, the nose of the sear will hit the fly and bounce over it (and the notch) allowing the tumbler and hammer to rotate to the fired position.

The fly cannot always be positioned to block off the half cock notch or the nose of the sear could never enter it to put the gun on "safe".
Because of this, the fly can rotate.

If the lock is in the fired position and the hammer is raised, the nose of the sear will drag along the outside of the tumbler until it reaches the fly.
When the sear nose hits the fly, it pushes against it, rotating it out of the way.
With the fly out of the way, the nose of the sear can enter the half-cock notch.

This is the reason that if the lock has a fly in it, you can not lower the hammer from a full cock position directly to the half-cock position.
You must first lower the hammer further down than "half-cock" and then raise it back up a little bit to place the gun into a "safe" position.

OK EVERYBODY!!! The classroom bell is about to ring. Don't forget to do exercises 2 thru 5 at the end of chapter 7 and be ready to turn them in tomorrow. :grin:

 

[Juice Jaws]

Expanding on Black Hand's explanation, guns using a simple trigger usually doesn't need a lock with a fly in the tumbler.

When the lock is released by a simple trigger the continuing pull of the shooters finger keeps the nose of the sear that held the tumbler at full cock, away from the half cock notch as the hammer is falling.
I am always impress the way you can explain the hard and make it simple. I always learn and enjoy your post. Oh, done the
If the gun has a "set trigger", things are different.

In case your new to locks, the sear is the thing the trigger pushes against to release the lock and let it fire the gun.
The sear holds the tumbler in position by positioning its hardened end into the half or full cock notch on the tumbler.
When the sear is released, it moves the end (nose) out of the notch.

Getting back to the set trigger, when the set trigger is released a heavy spring causes the (usually) rear trigger blade to snap upward and whack the sear's arm, knocking its nose out of the full cock notch on the tumbler.
Almost instantly, the set triggers blade bounces off of the sear arm.
The sear spring then rapidly pushes the sear nose back against the now rotating body of the tumbler.

If this happens quick enough, as it almost always does, the nose of the sear is set to pop into the tumblers half cock notch as it rapidly approaches.

If there is no fly in the tumbler, the nose of the sear will enter the half-cock notch and instantly stop the hammer from falling. (This can often result in a broken sear or half cock notch.)

If there is a fly in the tumbler, the body of the fly will block off the half cock notch so the sear can't enter it.
Instead, the nose of the sear will hit the fly and bounce over it (and the notch) allowing the tumbler and hammer to rotate to the fired position.

The fly cannot always be positioned to block off the half cock notch or the nose of the sear could never enter it to put the gun on "safe".
Because of this, the fly can rotate.

If the lock is in the fired position and the hammer is raised, the nose of the sear will drag along the outside of the tumbler until it reaches the fly.
When the sear nose hits the fly, it pushes against it, rotating it out of the way.
With the fly out of the way, the nose of the sear can enter the half-cock notch.

This is the reason that if the lock has a fly in it, you can not lower the hammer from a full cock position directly to the half-cock position.
You must first lower the hammer further down than "half-cock" and then raise it back up a little bit to place the gun into a "safe" position.

OK EVERYBODY!!! The classroom bell is about to ring. Don't forget to do exercises 2 thru 5 at the end of chapter 7 and be ready to turn them in tomorrow. :grin:

I am always impress how you can explain the hard and make it simple. I always learn from your posts and enjoy them. Oh, done the homework but when I went to get it this morning found out the dog ate all of it.

 

[rich pierce]

A simple trigger made to have a light trigger pull around 3 pounds often needs a lock with a fly in the tumbler as well.

 

[Artificer]

A simple trigger made to have a light trigger pull around 3 pounds often needs a lock with a fly in the tumbler as well.

YES!!!! I cannot even begin to describe how many times I looked longingly at Real Parker Hale "Whitworth" Tumblers that came with fly's in them and wished I could have legally put them in Real Parker Hale and Original Enfields for NSSA National Competition. However, it was not legal, so I would sigh and go on and do major modifications to the tumbler that were legal.

If I had the choice between a tumbler with a fly or a tumbler without a fly for a single trigger gun of any type, I would always choose the tumbler with a fly.

Gus

 

[stubshaft]

+1 - It is a must have for a decent light single trigger.

 

[Rifleman1776]

The fly is very tiny. I have heard some people have dropped and lost them when cleaning a lock then have problems. That's just 'some people'. I have never done it. :redface:

 

[Kansas Jake]

Always look in the ointment first! :grin:

 

[ol vern]

theirs them that has and them that hasn't --yet :haha:

 

[Gene L]

Always look in the ointment first! :grin:

Then, in your soup.

 

[tenngun]

It’s funny, when you see one and work the lock you see it right off. Even the modren works of a TC coil spring lock, yet it takes a book to explain it.

 

[Zonie]

When I take apart a lock with a fly in it, all attention is directed towards that fly.

As soon as it can be removed, I stick it onto a piece of masking tape and then place the tape somewhere safe where it can be easily found later.

While talking about flys, the one in the TC and Lyman locks have a small leg on them and they can only be installed one way.

Many of the L&R locks flys are just small, flat, oddly shaped pieces with a hole in them.
The hole fits over a pin that is cast into the tumbler.

Because of this, there is a 50/50 chance that you will install the fly upside down.

If this happens, the shape on the outside of the fly will not bump the nose of the sear over the half cock notch and often over itself.

If this happens, remove the fly, turn it over and then reinstall it on the pin.

It's not a bad idea to take a close up digital picture of the fly before removing it from the tumbler. Either that, or look at the fly closely with a magnifying glass and make a sketch of how the shape should look when it is installed correctly.

 

[bender20]

Just echoing the taking of a picture. With our modern phones so easy to do. Saved me many a headache on various projects around the house and car. A puzzle is always much easier when you have a picture of what it is supposed to look like when it is done. After many years of forgetting and much cussing I no longer disassemble anything.

 

[garra]

The fly is very tiny. I have heard some people have dropped and lost them when cleaning a lock then have problems. That's just 'some people'. I have never done it. :redface:

When I was working on my lock the other day after shooting, I looked at the tumbler and no fly, but it was there. Dragging a strong magnet across the carpet got it back, they sure are small.

 

[dodger]

The fly is very tiny. I have heard some people have dropped and lost them when cleaning a lock then have problems. That's just 'some people'. I have never done it. :redface:

When I was working on my lock the other day after shooting, I looked at the tumbler and no fly, but it was there. Dragging a strong magnet across the carpet got it back, they sure are small.

A small metal detector is also useful .
Sometimes a magnet won't find it but a metal detector will and vice versa .
A dab of grease will hold the fly during reassembly and can be washed out later with brake cleaner , or other degreaser.

 

[Adui]

Tell you what; after reading all this about losing small but important parts I think I am VERY happy I have not had to disassemble my lock ever.. Pray it continues to be so!

 

[rich pierce]

When I take apart a lock with a fly in it, all attention is directed towards that fly.

Many of the L&R locks flys are just small, flat, oddly shaped pieces with a hole in them.
The hole fits over a pin that is cast into the tumbler.

Because of this, there is a 50/50 chance that you will install the fly upside down.

If this happens, the shape on the outside of the fly will not bump the nose of the sear over the half cock notch and often over itself.

If this happens, remove the fly, turn it over and then reinstall it on the pin.

.

I found I’d lost the fly on my L&R lock and had a shooting match the next day so I made one. Ok I made 4 and the 4th one works.

In the process I learned enough to be able to make a fly without a picture or template. I think.

 

[Davemuzz]

I found I’d lost the fly on my L&R lock and had a shooting match the next day so I made one. Ok I made 4 and the 4th one works.

In the process I learned enough to be able to make a fly without a picture or template. I think.

I've been in situations like this.....for items like trigger springs, Ejector springs, plungers or any other tiny part that can seem to fly across my garage and disappear into nowhere. I've attempted to make parts for those lost items with about a 20% success rate.

Yet.....I continue to try. I must like committed to this.....or I'm nutz. Yeah......gotta be one or the other!! :rotf: :rotf: