sear location

[bjmac]

I'm building my first rifle. The lock plate is inletted as is the tumbler. What is the best way to locate the sear hole into the stock.? Should I make horizontal/vertical measurements or is "eyeball" from the plate? 

[Keb]

You can transfer the sear screw through the lock plate in the lock mortise. Then put a pivot pin in that screw hole & swing the sear around the pin for the location.

[Dave B]

Keb is right on,  Using a drill to plunge in to the screw holes gives a easy way to identify the position of the sear, tumbler and bridal with out having to reassemble the lock. Before seeing some one do it this way I used the " this is where it looks like it should go" as used by Wallace Gusler in Gunsmith of Williamsburg. He laid the lock on the stock blank and took a hammer and whacked the assembled lock driving he sear into the wood to make his mark for starting the whole lock inlet.

[D. Taylor Sapergia]

With the sear still in the lock, I study the extreme travel of the sear's bar, so that I can make a recess for it that is large enough.  Then with the sear off the plate, I mark the sear screw hole with a pencil.  Then I lay the sear against this mark, but upside-down, so the bar is sticking straight up.  It doesn't matter that the rest of the sear sits in the wrong spot - the tail lays correctly.  Then I mark those extreme travel locations, drill a 1/4" hole with a brad point drill and a drill press.  Then it's just a matter of using chisels to enlarge the hole in the areas where the sear bar needs clearance.  In most cases, the hole comes dangerously close to the lower edge of the plate inlet, so be careful where you drill the hole.  that's why I use a brad point drill...it keeps the bit from wandering and it also yields a flat bottomed hole.

[Vomitus]

Taylor,good info. Sounds like you're doing one now?! lol

[D. Taylor Sapergia]

Here are three examples of lock inlets, in particular, the sear location.  the last is the one to which Leatherbelly was referring...my Verner pistol build.

[Tim Crosby]

 If you are using a drill press be sure and clamp the stock to the table and set your stop or you may end up with a see through sear hole. Also that it is square to the table.

  Tim C.

[Eric Krewson]

I was fitting my lock and trigger a couple days ago on my fowler build. I had a 5/16" hole drilled for the sear, looked like plenty of room but when I tried the trigger my lock only came from full to half cock.

I blacked the sear bar and gave the trigger another try, same thing. Pulled my lock and found a slight black line in the upper side of the hole I drilled for my sear, I wasn't getting enough sear tavel to set my lock off. I had already expanded the hole from earlier tests when the lock wouldn't release at all.

My sear hole was pretty ragged at this point. I used a 3/8" forstner bit to enlarge my sear hole with my stock firmly clamped in my drill press vise.

The forstner bit will trim the most ragged hole to perfect dimensions. In this case I had to go through a half moon shaped portion of my lock plate mortise before I got to my sear hole. The forstner made this cut precisely, no chatter or walking.

My lock functioned just fine with a little extra wood removed.

[Captchee]

  
   this is how i do it .
 after the lock plate is properly inlet , i screw the sear back onto the  lock  plate with the tumbler in place .
  Using a pencil I make a vertical line  on the out side of the plate  that is center of the  sear arm .
 I then  make 2 horizontal lines . 1 with the sear fully disengaged  and 1 With the sear in the full cock notch .

 I then remove the sear and tumbler and place the lock plate back into the stock .
 Then carry the lines  out onto the stock .
 Remove the lock plate and  carry those lines down into the inlet .

 You now have the exact location of the sear arm and  its minimum limits of travel  

doing it this way also helps with setting the trigger or triggers  as i now know right where the lowest  level of the sear arm is

[B.Habermehl]

I normally drill the sear arm mortice with a forstener bit, with the shank marked with a line for a stop reference.  Looking at the stock from the top or bottom, I establish my stop mark by measureing from the lock panel surface to the centerline of the stock and add 1/4 to 5/16 in. This will usually give you enough depth for clearence for the end of the sear arm. As you will see there is ample wood left to prevent a see through mortice. BJH

[bjmac]

Thank you all for your replies and instructions. I was very concerned with the sear hole location in relation to the bottom of the plate, but I can see from Taylor's pictures that my initial placement is very close to correct. Tomorrow I'll give the drill press the workout and let you all know just how the results are!