Sunday, November 28, 2010

Trigger Blade for IZH 61

Thought this was going to be a really easy evening project--just a quick trigger blade replacement for my IZH-61. Ended up taking quite a bit of time due to my over complication of the design and the method of finishing.

The original trigger is pretty simple. A triangular piece of steel with a pinch clamp to hold it on the 3mm trigger rod. Lot of guns are using a rod like this to attach the trigger blade. Mostly European target guns--including some of the pistols.

Overall, this trigger is a nice design--especially considering this gun costs well under $140. It allows for axial adjustment and it's offset for a right-handed shooter. There is also a minimal amount of height adjustment available.

It's just a bit too small for my preference and I find that the curve doesn't quite fit my finger. Yeah, I'm nitpicking. I know. But it's an excuse to do something about it.

Sawed out a piece of aluminum. It's roughly 1" x 0.5" x 0.5". Milled the saw marks off.

Nick posted an excellent tutorial on milling set ups a few days ago on one of his machining blogs.

Found the center.

A little dykem layout fluid, and I used the caliper to mark a center line. Picked a promising location for the trigger bar and through drilled.

Worked my way up to a 3mm drill bit. This will just barely fit over the rod.

Could've just drilled a hole for a set screw and been halfway done--but nooooo. I think I did this the hard way. Wanted a pinching mechanism and since one pinch bolt would have sufficed, I decided to use two--opposed.

With an arbor attached to the headstock and a slitting saw blade mounted, I set the block in the milling attachment vise...

and cut a full length slot. The cut extended into the through hole.

Next, I drilled the pinch bolt holes. Drilled through both with a #40 bit. Then drilled partially through with a 3mm bit for clearance. Turned the piece over and drilled partially through on the other hole. The bolts will thread in from opposite sides.

Tapped the opposed #40 holes to M3 x 0.5mm

Cut between the pinch clamps so they'll function independently.

And started cutting away at the excess metal under the clamps.



Cut out a rectangle--scrap.

Getting there. Not shown: Milled the clamp on each side to pocket the clamping screw heads so they don't stand proud on the sides of the blade.

Like so.

It's still too blocky--even for a Russian gun--so it's going back for more milling.

The set-ups took the most time, but I milled each and every face. Shaped the back side of the trigger blade.

Beveled the the angles with a small needle file.

Ended up leaving all the milling marks. It looks jeweled from every angle. It's incredibly smooth. I thought there might be some texture from the milling marks, I was wrong.



Pulled the 3 screws and dropped the action out of the stock.

Removed the trigger blade with a flat head.

And screwed the trigger to the rod.

Also adjustable for angle like the original, but it's longer with a much broader face. The width feels just about ideal.

Added a few more pics 12-05-2010:

A bit better close up to show the milling cutter swirls.

The face is dead flat. No texture at all.

Haven't checked, but I think this will fit my Aeron target pistols, too.
**UPDATE 12/05/2010. Nope, won't fit the Aeron.

I'd like to make another trigger like this (though not nearly as time intensive) for another gun. We'll see.

1 comment:

ajsphoto said...

Great project! You're lucky I just bought a IZH 61 but they have discontinued the adjustable trigger. Still, the trigger isn't too bad, but it would have been better if I could have adjusted it.

Kudos to you and your great blog!