Apex Gunsmithing
7Jan/14

LH9 Breakdown Part 2: Process and Thoughts

Before I get into a detailed and illustrated step by step tutorial, I figured I would post a quick order of operations and some thoughts on the Daewoo design.  That includes how the mysterious Triple Action system works, some comments on design and a few major "gotcha" spots that will save time and aggravation.

Safety first, as always.  You know the drill: clear, double check, isolate ammo away from work area.

  1. Field strip the pistol, removing the slide and setting it aside.
  2. Let the hammer down, remove the grips.
  3. Press in on the hammer spring cup to de-tension it, push out pin with a punch.  Remove cup and hammer spring.
  4. Remove the trigger bar spring: compress it down to remove the top hook, lift up to remove bottom hook, pull spring straight up out of its little hole in the frame.
  5. Disengage the trigger return spring from the trigger bar peg.  Remove trigger bar.
  6. Remove trigger and trigger spring, if desired.  It doesn't get in the way if left in.
  7. Use 1/16" punch to drive the tiny roll pin in the left side of the safety down PART WAY.  It cannot come all the way out without scraping the frame, but will remove far enough to lift the left hand safety off.  Remove right hand safety now that it's not connected.
  8. Hammer pin is now exposed.  Remove right to left, noting the head on the pin and the recess it lives in.  Can't put that one in wrong.  Hammer and firing pin block lever will come out.
  9. Hammer strut can now be removed out of the top of the frame.
  10. Push the sear pin out, either direction.  Don't lose the spring.
  11. The mag catch can be removed by taking a small pick or hook and pulling the crook part of the spring out of the hole it lives in.  Remove spring, mag catch button will slide out.
  12. The ejector is held in by two small roll pins.  The slide stop detent plungers are similarly retained by a single pin.  The left side plunger is notched, the right side has a collar so it can only stick out so far.  Spring in between.

That's the complete process of disassembly.  Not too bad.  Magazines come apart like any pistol mag, depress the floorplate lock and slide it off.  The slide we will get to another day.

  • Grip screws have rubber grommets, interesting.
  • Those familiar with the Beretta 92 will note the similarities in the hammer spring cup and trigger bar spring.
  • After removing the safety, push the tiny roll pin through completely and start it on the top side.  This makes it much easier to reinstall it later, and to avoid losing the pin.
  • A hook is invaluable for re-connecting the trigger spring to the trigger bar peg, as well as forcing the sear spring down to push the sear pin through
  • Speaking of sear springs, the bent leg goes up, facing the sear.  Make sure it's sitting in the little notch in the sear.
  • The hammer strut is one of the last parts out, but MUST be reinstalled first thing before the hammer since it can only go in from the top of the frame.  It needs to seat on the underside of the hammer, so bring your borelight to peer down in the frame and get it in place.
  • If the hammer clicks over into Triple Action mode at any point, don't panic.  Put it together normally, and when putting pressure on the spring cup and hammer spring you will hear a solid CLICK.  That's just the hammer sear snapping back into neutral position.

So what's the deal with Triple Action/DA+?  The basic gist for those unfamiliar is that when the hammer is cocked, it can then be forced forward without letting it down in the typical fashion.  You then have the mainspring tensioned, but the hammer down and internal safeties engaged.  Touching the trigger will cause the hammer to flip back to fully cocked, and allow a single action shot instead of a heavy double action pull.  It's a system that is very clever but takes getting used to, and one that many people don't seem to understand the purpose of.

How does it work, though?  Well, that's the clever part.  The hammer is composed of three major parts, plus a spring and plunger.  The hammer itself has no sear hook(s) like say a 1911 or CZ does, instead there is a slice cut in the center of the hammer and a small cog inserted into it which has a single, centrally located sear surface.  The cog and hammer are held together by a bushing that rides on the hammer pin, so both parts rotate as a unit when the hammer is cocked manually.  The sear on the cog piece catches on the actual spring loaded sear, the F-shaped piece in our diagram from earlier.  Pulling the trigger pulls this spring loaded sear forward and drops the hammer.

What happens when you push the hammer forward is that the hammer itself rotates... but the cog in the middle doesn't.  It stays fixed in place, engaged to the sear, and the spring loaded plunger going over center provides the snap forward and back detent action.  When the trigger is pulled slightly the "feet" on the hammer are bumped, causing the hammer body to once more go over center and flip rearward to cocked position.  The whole time, the actual sear system remains stationary.

There are a couple of built in safety mechanisms that work passively to prevent any sort of accidental discharge.  The same trigger bar motion that trips the sear also activates the firing pin block lever and deactivates the plunger, so the firing pin will always remain blocked without a proper trigger pull.  On the sear itself there is a sizable shelf which acts as a drop safety, preventing any jar-off situations from allowing the hammer to fall fully in a similar manner to the half-cock or safety notch of a 1911.  Again, if the trigger is not pulled fully the sear is not moved out of the way meaning the "feet" of the hammer will catch the shelf long before the hammer contacts the firing pin.

Mystery solved!  And a lot of interesting design insight learned in the process to boot.  Stay tuned for illustrations and further comments on the Daewoo design and Lionheart pistols!

Comments (0) Trackbacks (0)

Sorry, the comment form is closed at this time.

Trackbacks are disabled.