What is the method for replacing the tab in the knuckle of a Fox ejector gun that interfaces the mainspring guide with the ejector sear in the iron? I’m calling it an ejector sear trip. The tab seems to be made as a unit with a surrounding bushing in the knuckle. Without this piece, nothing trips the ejector sear.

Thank for your help!

The bushing itself holds that tab/trip in place.

The tab has two small wings on it, one on each side that ride in slots cut in the bushing from the back end of it.
Those slots allow the tab to slide back and forth the small distance it needs to.
The tab can't exit the front as the slots are blind and don't allow it.
The tabs can't fall back into the frame as the hole the bushing w/the tab sits in has a slight shoulder at the rear. Just enough to block the slots.

To remove the bushing w/ the tab in it you need a long very slender punch. Long enough to reach from the rear of the action to the rear of those bushings.
The punch diameter must be small enough to allow it to catch the edge of the rear of the bushing but yet clear the horizontal placement of the tab that's in that bushing.
Not a lot of room...

You can guesstimate by looking at the outside face of the setup on the knuckle what is inside there.

First scratch a very light Witness mark accross the face of the bushing and onto the frame. You will want to be able to exactly line up the assembly when it goes back together so the mainspring follower can slip over the tab on the inside w/o binding things up.

Also keep Left and Right side pieces separate.
There's a top and bottom to the Tab also,,a slight radius to the underside of the tip that trips the ejector. That makes for easy retraction back into the frame as the gun closes.

Remove the hammer and the mainspring and follower.

Place the punch down into the mainspring hole from the rear of the frame.
CArefully place the tip of the punch onto the edge of the bushing at the far end of the mainspring hole.
You will be doing this by feel,,,you will feel the tab extension inside there with the punch. You can see the tab move on the outside /knuckle end if you're not in the right position.
The punch will easily lay on top of or underneath the tab. At that point you will not damage the tab and the nose of the punch will be against the edge of the bushing.

Gently tap on the punch and push the bushing out the front of the frame.
The tab usually comes out with it but if not it'll just be free to pull out with your fingers as there is no mechanical attachment.

The end of the bushing should already have been marked with an allaignment/witness mark.
Now is a good time to mark the bushing & tab L or R.

Installing them, just tap them carefully back in place using the witness and L/R marks for placement.

Bushings are usually soft, I clean them up a bit as they often are kind of crudely cut for the slots.
A couple have come out in pieces and were brittle (Case Hardened in place?)
I annealed them and the broken pieces. Then hard solder them back together. Trim the assembly up a bit in the lathe and back to work the go.

I've made the tabs from hacksaw blades in the past. Annealed just a bit from their 'saw blade' status and the matrl works well for the job if you have the right thickness worn out blades around.
Probably not Gunsmith PC, but neither am I.

Kutter great instructions! Thanks Bobby

Fantastic, Kutter. I’ll be trying this tonight in class. Hoping it goes well.

Made one out of a cheap eBay center gauge that was .045” thick, which is just .004” thinner than the stock part. The new part worked great, and then the other original snapped. Made another, and all is well on both sides.

Thank you!