Make a Trigger-Assembly Tool For the Winchester Model 12

"m I always interested in any tool that speeds up or simplifies the reinstallation of parts in a firearm. It’s great when a specialty tool can be purchased inexpensively, but I’m even happier when I can fabricate the gizmo myself. The reason I like to make tools whenever I can is because some of them get used so infrequently it just doesn’t make sense to tie up a lot of money in something that gets little use.

Then again, there are times when making a tool is our only option, such as in the case of tools that are no longer available. That’s the case with this tool, which comes from a drawing done in 1957 by A. A. Arnold that was included in the takedown instructions for the Winchester Model 12 shotgun. That was back in the days when Olin owned Winchester. Here, I’ll go over what’s involved with making this simple gadget and how it works to help get the trigger back in place in the trigger guard for the Model 12.

The tool will cost only a few bucks and will take very little time to make. Basic Materials You’ll need apiece of cold-rolled steel flat stock, 4-1/2 inches long by 7/ 8 inch wide and 3/16 inch thick. Cold-rolled steel (1018) is a mild steel that can easily be filed and drilled and comes, as rolled, in a very flat state. Once you have procured your steel stock and cut it to length, make sure at least one end is square to one side. If you have access to a milling machine, this is apiece of cake.

If not, the careful use of a file will bring the end into square. Next, paint one side of the flat stock with blue layout dye. (A black felt-tip pen will work if you have no layout dye available.) The end you squared up will be your starting point, so scribe a line 9/16 inch from this end and then scribe a line 3/ 16 inch from the squared-up bottom that crosses the previously scribed line (see Figure 1 ). Another line is then scribed 1-1/4 inches from the front end of your flat stock.

Now, scribe another line from the end of the first line to the point marked 1-1/4 inches back from the front face. This will complete the layout of the notch that will need to be cut on the bottom of the flat stock. Another line will need to be scribed 11/16 inch from the bottom edge of the flat stock, 1-7/8 inches from the front end.

The last two lines we need to scribe are from the other end of the flat stock and will be for a hole so that we can hang our masterpiece up on the wall for easy access and for the whole world to ask: "What’s that thing for?" Scribe a line in the middle of the flat stock along the top side of the part and then an intersecting line 3/4 inch from the rear edge of the flat stock. Center punch the intersect point, giving it a fairly deep dimple so that a drill bit can start cutting without walking off target.

Shaping the Assembly Tool Now that we have all the basic lines scribed, it’s time to get this thing shaped into a usable form. Clamp the

part in your vise with the front end sticking out the right side of the jaws so you can work a hack saw freely. Cut a series of notches stopping just short of the scribed, angled line. The more notches you cut the less work you’ll have to do with a file. Using a flat bastard-cut file, you’ll be able to get the angled notch very close to shape in short order. When you get close to the bottom of the hack-saw notches, a second-cut triangular file can be used to give the surface a fairly smooth finish.

The top part of this tool can be treated the same as the angled notch by using the hack-saw to remove the bulk of material and then finishing up with a smooth-cut file. To transition the step that was just created at the top of the tool, a 45-degree angle or a radius will eliminate any sharp corners. One more cut that will need to be made is a 45-degree angle at the top, front of the tool. Measure 1/4 inch back from the top left corner of the tool and mark a small line.

Place another mark 1/4 inch down from the top, upper left corner of the tool. Using a straightedge, scribe a line connecting these two marks leaving a 45degree reference line. Here again, the hack-saw can be used to remove the bulk of material up to, but not over, the line. Finish this area with a second-cut file. On the very front end of the tool, drill a hole to accept a 9/64-inch pin.

Dye up the front edge of the tool with whatever you’re using, and scribe a line 1/4 inch up from the bottom of the tool along the side of the part that we previously dyed. Scribe another line along the front edge (3/16 wide area) at the 1/4 inch mark. Another line needs to be scribed dead center in the middle of the 3/16 inch thickness so that it intersects the other line. Dimple the intersect point with a sharp punch and then drill a 9/64 inch hole into the end of the tool, 3/8 inch deep.

We now need a pin to insert into the 9/64-inch hole that was just drilled in place. If you have access to a metal lathe, it’s a simple matter to turn a pin to press fit into the drilled hole. If you don’t have access to a lathe, 9/64-inch round stock is available that can be cut to 3/4 inch length and installed in the hole. Keep in mind that the drill most likely created a hole that is slightly larger than the 9/64-inch diameter pin we need to insert into this tool.

If you find that the pin drops into place with some looseness, use your punch to dimple the periphery on the end of the pin you will be inserting into the tool. This will increase the outside diameter of the pin in that area, and when you insert the pin, add a coating of permanent thread locker to anchor the pin in place. Figure 1. Now is a good time to drill the hanger hole in the rear of the tool.

As you can see by the example shown here, I rounded the rear end of mine so that there would be no square corners digging into my palm when the tool is being used. Another nice touch is to slightly round all the edges and corners by smoothing these areas with a fine-cut file or apiece of emery paper.

Using the Tool When reassembling the Winchester Model 12 triggerguard assembly, it can be extremely difficult to hold the trigger in place while it’s under tension from the spring that makes it work, and to then slip the retaining pin through the left wall of the trigger guard. With this tool, you insert the 9/64 inch pin into the hole for the hammerspring guide rod in the trigger guard, and then push the tool downward, compressing the tension of the trigger spring.

With a little wiggling, you can easily line up the hole in the trigger with the hole in the trigger guard and insert the pin. I