nobody1369
32 Cal.
- Joined
- Feb 15, 2010
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- 8
what is the purpose of the fly in my lock
-
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FLIES
- Thread starter nobody1369
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When you trip the trigger/sear it allows the sear to clear the tumbler. Without it the sear would in most cases slam into the half cock position making the gun unable to fire.
Welcome to the forum. 
The fly is located at the mouth of the half cock notch in the tumbler. The flys job is to rotate out of the way and expose the half cock notch when the hammer is being raised from the fired position, allowing the nose of the sear to enter the notch.
When the hammer is raised further the nose of the sear jumps over the fly and continues until it (the sear) falls into the full cock notch.
When the sear is released from the full cock notch, IF the trigger was a "set" "set trigger" the sear is only momentarily moved out of the full cock notch. Then the sear spring will push the nose of the sear back against the outside of the tumbler.
As the hammer falls, the nose of the sear will come back to the fly and push it forward. In this forward position the fly will block off the entrance to the half cock notch forcing the sear to "jump over" it. This allows the hammer to continue to fall to the fired position.
In guns that do not have a "set trigger" or a fly in the lock the shooters finger will hold the trigger to the rear which in turn keeps the sear raised up off of the outside of the tumbler.
In this raised position the half cock notch will pass by the sear without a problem as the hammer continues to fall.
While I'm writing, although you did not ask about set triggers you might be interested in the following:
There is one type of set trigger that is made for use with locks that do not have a fly.
This type of set trigger is known as the Double Set Single Lever trigger.
It is designed so that if it is not set or has been released from a set condition its lever always pushes up on the sear arm causing the nose of the sear to clear the body of the tumbler.
With this type of trigger the shooter must first set the trigger before cocking the gun. If he tries cocking the gun without first setting the trigger it will not engage the full cock notch.
Because the lock cannot be set unless the rear trigger is "set" the front trigger does not have to be able to fire the gun when the set trigger is not set.
As the front trigger doesn't need to be able to fire the gun by itself, set triggers of this style do not have a lever or blade on the front trigger. This explains why they are called Single Lever triggers.
These triggers are usually found on target rifles.
The fly is located at the mouth of the half cock notch in the tumbler. The flys job is to rotate out of the way and expose the half cock notch when the hammer is being raised from the fired position, allowing the nose of the sear to enter the notch.
When the hammer is raised further the nose of the sear jumps over the fly and continues until it (the sear) falls into the full cock notch.
When the sear is released from the full cock notch, IF the trigger was a "set" "set trigger" the sear is only momentarily moved out of the full cock notch. Then the sear spring will push the nose of the sear back against the outside of the tumbler.
As the hammer falls, the nose of the sear will come back to the fly and push it forward. In this forward position the fly will block off the entrance to the half cock notch forcing the sear to "jump over" it. This allows the hammer to continue to fall to the fired position.
In guns that do not have a "set trigger" or a fly in the lock the shooters finger will hold the trigger to the rear which in turn keeps the sear raised up off of the outside of the tumbler.
In this raised position the half cock notch will pass by the sear without a problem as the hammer continues to fall.
While I'm writing, although you did not ask about set triggers you might be interested in the following:
There is one type of set trigger that is made for use with locks that do not have a fly.
This type of set trigger is known as the Double Set Single Lever trigger.
It is designed so that if it is not set or has been released from a set condition its lever always pushes up on the sear arm causing the nose of the sear to clear the body of the tumbler.
With this type of trigger the shooter must first set the trigger before cocking the gun. If he tries cocking the gun without first setting the trigger it will not engage the full cock notch.
Because the lock cannot be set unless the rear trigger is "set" the front trigger does not have to be able to fire the gun when the set trigger is not set.
As the front trigger doesn't need to be able to fire the gun by itself, set triggers of this style do not have a lever or blade on the front trigger. This explains why they are called Single Lever triggers.
These triggers are usually found on target rifles.
nobody1369
32 Cal.
- Joined
- Feb 15, 2010
- Messages
- 18
- Reaction score
- 8
this sounds like the triggers that i have, you must set the rear trigger before cocking. the fly seemed to be interfering with the half cock, i removed it and half cock works perfectly.
Having mentioned the Double Set Single Lever style trigger I should mention that a incorrectly installed Double Set Double lever style trigger will also act like the single lever trigger.
To determine which style of double set trigger you have, remove it from the stock.
With the trigger assembly removed, pull back a bit on the front trigger. If you see a blade (lever) raising up out of the assembly you have a Double lever style that should allow the lock to be cocked without first setting the rear trigger.
If you have a double lever trigger AND you want to be able to cock and fire the gun using only the front trigger you can fix it.
Often the trigger assembly is installed to deeply into the stock causing the rear triggers lever to push up on the sear arm when it is in the unset condition.
To fix this, install a shim between the stock and the trigger plate.
On some double set double lever triggers there is a small headless set screw BEHIND the rear trigger.
This screw is there to allow for the adjustment of the rear triggers spring.
If it is not screwed in far enough the spring will cause the rear triggers lever to "ride too high" making it push on the sear arm.
By screwing this little set screw IN, it will raise the spring allowing the rear triggers blade to fall down a bit so it doesn't interfere with the sear arm when it is not set.
Even though the raised spring will not be pushing on the rear trigger when it is unset, setting the rear trigger will still cause the spring to deflect and to do its job.
Another way of fixing this is to file the top of the rear triggers lever down so that it clears the sear arm when the rear trigger is not set.
These recommendations should only be followed IF your FRONT trigger does have a blade on it.
If you have a double lever trigger and fix the problem your lock will have to have the fly installed in it.
To determine which style of double set trigger you have, remove it from the stock.
With the trigger assembly removed, pull back a bit on the front trigger. If you see a blade (lever) raising up out of the assembly you have a Double lever style that should allow the lock to be cocked without first setting the rear trigger.
If you have a double lever trigger AND you want to be able to cock and fire the gun using only the front trigger you can fix it.
Often the trigger assembly is installed to deeply into the stock causing the rear triggers lever to push up on the sear arm when it is in the unset condition.
To fix this, install a shim between the stock and the trigger plate.
On some double set double lever triggers there is a small headless set screw BEHIND the rear trigger.
This screw is there to allow for the adjustment of the rear triggers spring.
If it is not screwed in far enough the spring will cause the rear triggers lever to "ride too high" making it push on the sear arm.
By screwing this little set screw IN, it will raise the spring allowing the rear triggers blade to fall down a bit so it doesn't interfere with the sear arm when it is not set.
Even though the raised spring will not be pushing on the rear trigger when it is unset, setting the rear trigger will still cause the spring to deflect and to do its job.
Another way of fixing this is to file the top of the rear triggers lever down so that it clears the sear arm when the rear trigger is not set.
These recommendations should only be followed IF your FRONT trigger does have a blade on it.
If you have a double lever trigger and fix the problem your lock will have to have the fly installed in it.
Ray-Vigo
Yankee
Listen to Zonie on this stuff-- I had a problem with a fly in a large Siler lock last year. I have a double set trigger and when using the set mechanism, the lock would jam down in half-cocked when trying to fire. I ordered a Siler fly and installed it myself using Zonie's instructions. It worked and now my lock is fixed for the set.
I will add that I was able to do it in only a few minutes' work with no prior lock disassembly experience thanks to the help I received on the boards, especially Zonie's instructions. It was a simple job on the Siler, though L&R apparently is harder.
I will add that I was able to do it in only a few minutes' work with no prior lock disassembly experience thanks to the help I received on the boards, especially Zonie's instructions. It was a simple job on the Siler, though L&R apparently is harder.
