Lock building- Fly or no fly

[wmaser]

When building my locks, I have always built them with a fly simply because I thought it was necessary when using a set trigger. When building from scratch, this is a real pain in the butt. Recently, however, I have been experimenting with halfcock notch placement and sear tip geometry and found that a tumbler, notched strategically, together with  an upward curving sear tip functions very well with a set trigger without the need for a fly. Surely, someone has done this before. Why use a fly if you don't have to? Have any other lock builders done this? Comments?

[Old Ford2]

Great observation!
Old Ford

[Captchee]

many years ago i played around with the idea of not adding a fly .
 Yes it can  be done , just as you found out .
 It also can be done by placing the  ½ cock in  a lower plain then the full cock  while at the same time making the notches closer together. As you said , strategically placed
 Personally  I could not reach a happy medium  in that I did not like  how close the ½ needed to be to the full .   I even went so far as to put such a lock on one of my rifles and then let a number of different folks shoot it . What I found though was that to often  when cocking the lock , they would end up at full cock when they thought they were at the ½ .

anyway thats my own experience.  

[wmaser]

Very true. The halfcock notch must be very close to the full but I find that, if filed deep enough, the halfcock emits a very distinctive click when engaged. That is unless the cock is pulled back very quickly in one sudden jerk.

[Stophel]

You know, the vast majority of locks 200 years ago didn't have flies either.   

[dannybb55]

Do like Henry Leman did and omit the half cock.

[wmaser]

I have omitted the halfcock position with a percussion lock, but in the case of a percussion lock, the gun can be carried with the hammer down and resting on the capped nipple. (I own an original Leman with no halfcock) But with a flintlock, when the cock is down the pan is open.
Stophel: Did those vast majority of locks have single or set triggers?

[Stophel]

The vast majority of guns had simple triggers anyway.   

[Dphariss]

Does it not occur to anyone that over centuries of lock making that this has in all probability been looked into and then abandoned?

Dan

[wmaser]

 Surely, someone has done this before. Why use a fly if you don't have to? Have any other lock builders done this? Comments?
[/quote]
Yes it occured to me. That's pretty much why I'm asking the questions.

[J. Talbert]

It only takes one cycle of the lock that's a little off and you could have a broken sear or tumbler.  We all probably consider ourselves good drivers, but who out there want's to go without car insurance?

Jeff

[Dphariss]

Surely, someone has done this before. Why use a fly if you don't have to? Have any other lock builders done this? Comments?

Yes it occured to me. That's pretty much why I'm asking the questions.


[/quote]

Apparently the lock for a set trigger rifle needs a fly or the flyless lock would be common in history.
Everything is a trade off. For example does the sear bar stay in the same location? This is one earmark of a quality lock.
If not its a PITA. The sear moves a lot and needs more wood removed to give clearance and there is lots of slop in the trigger and its position changes for full and 1/2 cock.
With set triggers there needs to be more clearance between the triggers and the sear bar. This means the rear trigger has to have more travel the hit the sear.  If double level triggers it may be difficult to get the front trigger to both clearance for 1/2 cock and still bear on the sear bar if needed for firing the gun.

If you look at a lock there are no extra parts. Everything here is there because it serves a purpose. The fly is not included just to make more work the the lock filer. Its obviously a necessary part for set trigger equipped rifles and this carried on for as long as set triggers were used on rifles that did not have striker ignition like the Borchardt. ALL the exposed hammer guns used them including all the late 19th century designs if the rifles were equipped with set triggers. 

Dan

[Stophel]

Only now have I noticed that the original question included the stipulation of a set trigger!   

To use a fly-less lock with set triggers, make it so that the trigger must be set before the lock can be cocked.  So that the trigger holds the sear up rather than just thumping it like normal.  Not the best way, but it does work.

That's the reason for the fly.  The set trigger just thumps the sear loose, and doesn't hold it up.

[dannybb55]

The real simple lock is the Underhammer. I saw the pic of a sweet one on an auction site last year made by JJ Henry.

[wmaser]

Dan,
 You obviously are very knowlegable about the construction and internal function of the lock components and I agree that during the centuries of evolution of the lock, form did follow function. However, an examination of my latest "flyless" lock, by me and a couple other shooters, found it to be perfectly functional without the fly. The sear bar maintains it's same location in the down, half and full cock positions. The only compromise noted was, as "captchee" stated, the notch locations in the tumbler do necessitate the halfcock and fullcock positions be fairly close.
I'm going to put this lock on a rifle and shoot it for a while and I'll let you know if I do experience any problems with it. I'm not trying to be argumentative, I'm just trying to share some information with like minded people.