Wednesday, January 13, 2010

Daisy 717 Trigger Refinement Part 2

Note: This modification dramatically alters the sear contact creating a dangerously light trigger. The gun will fire if dropped. It might fire if not dropped. Don't do this unless you take complete responsibility for what may happen. Seriously, don't try this at home.

The sear polish was helpful, but still not quite what I was after. I disassembled the trigger components again and dug in. Started by sanding the mold lines off the sides of the plastic trigger.

Used a piece of 1200 grit wet dry on a granite block. Just took off the high spots so there's no drag inside the grip frame. Not shown: Finished by buffing the sides on a sheet of thin cardboard embedded with Mothers Mag and Aluminum Polish. The sides were glossy when finished. Also not shown: Polished the inside of the grip frame with a fine Cratex abrasive wheel in the trigger area.

On to the Nygord trigger modification.

Spotted the inside of the grip frame with a center drill.

Then through drilled with a #43 (0.0890") drill bit.

Another view.

Since the #43 bit was still in the drill chuck, I measured the forward tab on the trigger. Divided by two and found the centerline and eyeballed a good spot just behind the tab for the safety.

Then drilled through.

Followed up with a #4-40 plug tap.

#4-40 set screw installed. This will function as a positive trigger stop inside the grip frame to limit trigger travel after the sear releases.

Tapped the frame with the same #4-40 size.

A dab of Dykem layout fluid on the bottom of the sear...

Like so.

Installed a 1/2" long #4-40 set screw,

and reassembled the trigger components.

Manually cocked the sear/cocking link, then turned in the set screw until I felt it "bite" into the bottom of the sear leaving this small mark in the Dykem.

Mounted the sear in the Taig lathe milling vise.

Used a 3/32" center cutting mill

And created a small shelf for the #4-40 set screw to bear against.

Reinstalled the trigger parts. This is the sear at full factory engagement.

By turning the set screw inward, it presses against the small milled flat and moves the sear backwards away from the cocking link. This decreases the sear contact and makes the smallest trigger pressure fire the gun.

The sear contact is literally on edge. This trigger adjustment will likely not hold up long term. The sear and cocking link are made from what appears to be die cast zinc or an aluminum. Why Daisy didn't use case hardened steel here is beyond me. However, Daisy didn't engineer this trigger to last with this little sear contact.

I've been warned that the set screw adjustment tends to wander over time, so I used a very low grade thread locker on the screw. The amount of screw movement to affect trigger pull, by the way, is extremely small. It only takes about one full rotation on the screw once sear contact is made to fire, with the correct adjustment being just before firing. So, any setscrew movement at all is detrimental to the trigger pull. Though, if there is movement, the set screw will only move downward--increasing sear contact. If I were to do this modification again, I believe a finer thread pitch on the set screw would be beneficial as there would be less travel on the sear per rotation. It would be easier to achieve sear adjustment.

Kinda blurry, but the trigger stop set screw is adjusted inward until the trigger will not fire then backed out incrementally until it does. Erred on the side of trigger function. I backed the screw out about 1/8 turn after the sear released.

I never would have believed that the 717 trigger could be this good. There's zero creep and a crisp release that's hovering around one pound.

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